diff --git a/core/api/core.api b/core/api/core.api
index 21ecce65f6..c82a7fc7f8 100644
--- a/core/api/core.api
+++ b/core/api/core.api
@@ -1300,6 +1300,7 @@ public abstract interface annotation class org/jetbrains/kotlinx/dataframe/annot
 public abstract interface annotation class org/jetbrains/kotlinx/dataframe/annotations/JsonOptions : java/lang/annotation/Annotation {
 	public abstract fun keyValuePaths ()[Ljava/lang/String;
 	public abstract fun typeClashTactic ()Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;
+	public abstract fun unifyNumbers ()Z
 }
 
 public abstract interface annotation class org/jetbrains/kotlinx/dataframe/annotations/Order : java/lang/annotation/Annotation {
@@ -9930,9 +9931,11 @@ public final class org/jetbrains/kotlinx/dataframe/impl/ExceptionUtilsKt {
 public final class org/jetbrains/kotlinx/dataframe/impl/TypeUtilsKt {
 	public static final fun getValuesType (Ljava/util/List;Lkotlin/reflect/KType;Lorg/jetbrains/kotlinx/dataframe/api/Infer;)Lkotlin/reflect/KType;
 	public static final synthetic fun guessValueType (Lkotlin/sequences/Sequence;Lkotlin/reflect/KType;Z)Lkotlin/reflect/KType;
-	public static final fun guessValueType (Lkotlin/sequences/Sequence;Lkotlin/reflect/KType;ZZ)Lkotlin/reflect/KType;
+	public static final synthetic fun guessValueType (Lkotlin/sequences/Sequence;Lkotlin/reflect/KType;ZZ)Lkotlin/reflect/KType;
+	public static final fun guessValueType (Lkotlin/sequences/Sequence;Lkotlin/reflect/KType;ZZZ)Lkotlin/reflect/KType;
 	public static synthetic fun guessValueType$default (Lkotlin/sequences/Sequence;Lkotlin/reflect/KType;ZILjava/lang/Object;)Lkotlin/reflect/KType;
 	public static synthetic fun guessValueType$default (Lkotlin/sequences/Sequence;Lkotlin/reflect/KType;ZZILjava/lang/Object;)Lkotlin/reflect/KType;
+	public static synthetic fun guessValueType$default (Lkotlin/sequences/Sequence;Lkotlin/reflect/KType;ZZZILjava/lang/Object;)Lkotlin/reflect/KType;
 	public static final fun replaceGenericTypeParametersWithUpperbound (Lkotlin/reflect/KType;)Lkotlin/reflect/KType;
 }
 
@@ -10077,7 +10080,7 @@ public final class org/jetbrains/kotlinx/dataframe/impl/api/ToDataFrameKt {
 }
 
 public final class org/jetbrains/kotlinx/dataframe/impl/api/ToSequenceKt {
-	public static final fun toSequenceImpl (Lorg/jetbrains/kotlinx/dataframe/DataFrame;Lkotlin/reflect/KType;)Ljava/lang/Iterable;
+	public static final fun toSequenceImpl (Lorg/jetbrains/kotlinx/dataframe/DataFrame;Lkotlin/reflect/KType;)Lkotlin/sequences/Sequence;
 }
 
 public final class org/jetbrains/kotlinx/dataframe/impl/api/UpdateKt {
@@ -10145,10 +10148,14 @@ public final class org/jetbrains/kotlinx/dataframe/impl/columns/ComputedColumnRe
 public final class org/jetbrains/kotlinx/dataframe/impl/columns/ConstructorsKt {
 	public static final synthetic fun createColumn (Ljava/lang/Iterable;Lkotlin/reflect/KType;Z)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
 	public static synthetic fun createColumn$default (Ljava/lang/Iterable;Lkotlin/reflect/KType;ZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
-	public static final fun createColumnGuessingType (Ljava/lang/Iterable;Lorg/jetbrains/kotlinx/dataframe/columns/TypeSuggestion;Ljava/lang/Object;Ljava/lang/Boolean;ZZ)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
-	public static final fun createColumnGuessingType (Ljava/lang/String;Ljava/lang/Iterable;Lorg/jetbrains/kotlinx/dataframe/columns/TypeSuggestion;Ljava/lang/Object;Ljava/lang/Boolean;ZZ)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
+	public static final synthetic fun createColumnGuessingType (Ljava/lang/Iterable;Lorg/jetbrains/kotlinx/dataframe/columns/TypeSuggestion;Ljava/lang/Object;Ljava/lang/Boolean;ZZ)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
+	public static final fun createColumnGuessingType (Ljava/lang/Iterable;Lorg/jetbrains/kotlinx/dataframe/columns/TypeSuggestion;Ljava/lang/Object;Ljava/lang/Boolean;ZZZ)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
+	public static final synthetic fun createColumnGuessingType (Ljava/lang/String;Ljava/lang/Iterable;Lorg/jetbrains/kotlinx/dataframe/columns/TypeSuggestion;Ljava/lang/Object;Ljava/lang/Boolean;ZZ)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
+	public static final fun createColumnGuessingType (Ljava/lang/String;Ljava/lang/Iterable;Lorg/jetbrains/kotlinx/dataframe/columns/TypeSuggestion;Ljava/lang/Object;Ljava/lang/Boolean;ZZZ)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
 	public static synthetic fun createColumnGuessingType$default (Ljava/lang/Iterable;Lorg/jetbrains/kotlinx/dataframe/columns/TypeSuggestion;Ljava/lang/Object;Ljava/lang/Boolean;ZZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
+	public static synthetic fun createColumnGuessingType$default (Ljava/lang/Iterable;Lorg/jetbrains/kotlinx/dataframe/columns/TypeSuggestion;Ljava/lang/Object;Ljava/lang/Boolean;ZZZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
 	public static synthetic fun createColumnGuessingType$default (Ljava/lang/String;Ljava/lang/Iterable;Lorg/jetbrains/kotlinx/dataframe/columns/TypeSuggestion;Ljava/lang/Object;Ljava/lang/Boolean;ZZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
+	public static synthetic fun createColumnGuessingType$default (Ljava/lang/String;Ljava/lang/Iterable;Lorg/jetbrains/kotlinx/dataframe/columns/TypeSuggestion;Ljava/lang/Object;Ljava/lang/Boolean;ZZZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
 	public static final synthetic fun guessColumnType (Ljava/lang/String;Ljava/util/List;Lkotlin/reflect/KType;ZLjava/lang/Object;Ljava/lang/Boolean;)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
 	public static synthetic fun guessColumnType$default (Ljava/lang/String;Ljava/util/List;Lkotlin/reflect/KType;ZLjava/lang/Object;Ljava/lang/Boolean;ILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
 	public static final fun newColumn (Lorg/jetbrains/kotlinx/dataframe/ColumnsContainer;Lkotlin/reflect/KType;Ljava/lang/String;Lorg/jetbrains/kotlinx/dataframe/api/Infer;Lkotlin/jvm/functions/Function2;)Lorg/jetbrains/kotlinx/dataframe/DataColumn;
@@ -10479,8 +10486,10 @@ public final class org/jetbrains/kotlinx/dataframe/io/HtmlKt {
 
 public final class org/jetbrains/kotlinx/dataframe/io/JSON : org/jetbrains/kotlinx/dataframe/io/SupportedDataFrameFormat {
 	public fun <init> ()V
-	public fun <init> (Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Ljava/util/List;)V
+	public synthetic fun <init> (Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Ljava/util/List;)V
 	public synthetic fun <init> (Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Ljava/util/List;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
+	public fun <init> (Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Ljava/util/List;Z)V
+	public synthetic fun <init> (Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Ljava/util/List;ZILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public fun acceptsExtension (Ljava/lang/String;)Z
 	public fun acceptsSample (Lorg/jetbrains/kotlinx/dataframe/io/SupportedFormatSample;)Z
 	public fun createDefaultReadMethod (Ljava/lang/String;)Lorg/jetbrains/kotlinx/dataframe/codeGen/DefaultReadDfMethod;
@@ -10498,26 +10507,42 @@ public final class org/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic : jav
 }
 
 public final class org/jetbrains/kotlinx/dataframe/io/JsonKt {
-	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/io/File;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
-	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/io/InputStream;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
-	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
-	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/net/URL;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
-	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/io/File;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
-	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/io/InputStream;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
-	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
-	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/net/URL;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static final synthetic fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/io/File;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/io/File;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Z)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static final synthetic fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/io/InputStream;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/io/InputStream;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Z)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Z)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static final synthetic fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/net/URL;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/net/URL;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Z)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static final synthetic fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/io/File;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/io/File;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Z)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static final synthetic fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/io/InputStream;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/io/InputStream;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Z)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Z)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static final synthetic fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/net/URL;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static final fun readJson (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/net/URL;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Z)Lorg/jetbrains/kotlinx/dataframe/DataRow;
 	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/io/File;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/io/File;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
 	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/io/InputStream;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
-	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/io/InputStream;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
 	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/net/URL;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/net/URL;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
 	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/io/File;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/io/File;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
 	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/io/InputStream;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
-	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/io/InputStream;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
 	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/net/URL;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
-	public static final fun readJsonStr (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
-	public static final fun readJsonStr (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static synthetic fun readJson$default (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/net/URL;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static final synthetic fun readJsonStr (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static final fun readJsonStr (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Z)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static final synthetic fun readJsonStr (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static final fun readJsonStr (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;Z)Lorg/jetbrains/kotlinx/dataframe/DataRow;
 	public static synthetic fun readJsonStr$default (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
+	public static synthetic fun readJsonStr$default (Lorg/jetbrains/kotlinx/dataframe/DataFrame$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataFrame;
 	public static synthetic fun readJsonStr$default (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
+	public static synthetic fun readJsonStr$default (Lorg/jetbrains/kotlinx/dataframe/DataRow$Companion;Ljava/lang/String;Ljava/util/List;Ljava/util/List;Lorg/jetbrains/kotlinx/dataframe/io/JSON$TypeClashTactic;ZILjava/lang/Object;)Lorg/jetbrains/kotlinx/dataframe/DataRow;
 	public static final fun toJson (Lorg/jetbrains/kotlinx/dataframe/DataFrame;Z)Ljava/lang/String;
 	public static final fun toJson (Lorg/jetbrains/kotlinx/dataframe/DataRow;Z)Ljava/lang/String;
 	public static synthetic fun toJson$default (Lorg/jetbrains/kotlinx/dataframe/DataFrame;ZILjava/lang/Object;)Ljava/lang/String;
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/annotations/ImportDataSchema.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/annotations/ImportDataSchema.kt
index ded7a366e9..184f10baf8 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/annotations/ImportDataSchema.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/annotations/ImportDataSchema.kt
@@ -4,6 +4,7 @@ import org.jetbrains.kotlinx.dataframe.api.JsonPath
 import org.jetbrains.kotlinx.dataframe.api.KeyValueProperty
 import org.jetbrains.kotlinx.dataframe.columns.ColumnGroup
 import org.jetbrains.kotlinx.dataframe.columns.FrameColumn
+import org.jetbrains.kotlinx.dataframe.documentation.UnifyingNumbers
 import org.jetbrains.kotlinx.dataframe.io.JSON
 
 /**
@@ -80,4 +81,6 @@ public annotation class JsonOptions(
      * `["""\$["store"]["book"][*]["author"]"""]`
      */
     public val keyValuePaths: Array<String> = [],
+    /** Whether to [unify the numbers that are read][UnifyingNumbers]. `true` by default. */
+    public val unifyNumbers: Boolean = true,
 )
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/TypeUtils.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/TypeUtils.kt
index 38be1760bf..b5f9635139 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/TypeUtils.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/TypeUtils.kt
@@ -363,7 +363,30 @@ internal fun <T> getValuesType(values: List<T>, type: KType, infer: Infer): KTyp
 @Deprecated(GUESS_VALUE_TYPE, level = DeprecationLevel.HIDDEN)
 @PublishedApi
 internal fun guessValueType(values: Sequence<Any?>, upperBound: KType? = null, listifyValues: Boolean = false): KType =
-    guessValueType(values = values, upperBound = upperBound, listifyValues = listifyValues, allColsMakesRow = false)
+    guessValueType(
+        values = values,
+        upperBound = upperBound,
+        listifyValues = listifyValues,
+        allColsMakesRow = false,
+        unifyNumbers = false,
+    )
+
+/** Just for binary compatibility, as it's @PublishedApi. */
+@Deprecated(GUESS_VALUE_TYPE, level = DeprecationLevel.HIDDEN)
+@PublishedApi
+internal fun guessValueType(
+    values: Sequence<Any?>,
+    upperBound: KType? = null,
+    listifyValues: Boolean = false,
+    allColsMakesRow: Boolean = false,
+): KType =
+    guessValueType(
+        values = values,
+        upperBound = upperBound,
+        listifyValues = listifyValues,
+        allColsMakesRow = allColsMakesRow,
+        unifyNumbers = false,
+    )
 
 /**
  * Returns the guessed value type of the given [values] sequence.
@@ -381,6 +404,10 @@ internal fun guessValueType(values: Sequence<Any?>, upperBound: KType? = null, l
  * @param allColsMakesRow if true, then, if all values are non-null columns, we assume
  *   that a column group should be created instead of a [DataColumn][DataColumn]`<`[AnyCol][AnyCol]`>`,
  *   so the function will return [DataRow].
+ * @param unifyNumbers if true, then all number types encountered will be unified to the smallest possible
+ *   number-type that can hold all number values lossless in [values]. See [commonNumberClass].
+ *   Unsigned numbers are not supported.
+ *   If false, the result of encountering multiple number types would be [Number].
  */
 @PublishedApi
 internal fun guessValueType(
@@ -388,6 +415,7 @@ internal fun guessValueType(
     upperBound: KType? = null,
     listifyValues: Boolean = false,
     allColsMakesRow: Boolean = false,
+    unifyNumbers: Boolean = false,
 ): KType {
     val classes = mutableSetOf<KClass<*>>()
     val collectionClasses = mutableSetOf<KClass<out Collection<*>>>()
@@ -443,6 +471,18 @@ internal fun guessValueType(
         classesInCollection.all { it.isSubclassOf(DataRow::class) } &&
         !nullsInCollection
 
+    if (unifyNumbers) {
+        val nothingClass = Nothing::class
+        val usedNumberClasses = classes.filter {
+            it.isSubclassOf(Number::class) && it != nothingClass
+        }
+        if (usedNumberClasses.isNotEmpty()) {
+            val unifiedNumberClass = usedNumberClasses.unifiedNumberClass() as KClass<Number>
+            classes -= usedNumberClasses
+            classes += unifiedNumberClass
+        }
+    }
+
     return when {
         classes.isNotEmpty() -> {
             if (hasRows) classes.add(DataRow::class)
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/columns/constructors.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/columns/constructors.kt
index 638a8a6475..84a6368b8e 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/columns/constructors.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/columns/constructors.kt
@@ -31,10 +31,13 @@ import org.jetbrains.kotlinx.dataframe.columns.ColumnsResolver
 import org.jetbrains.kotlinx.dataframe.columns.TypeSuggestion
 import org.jetbrains.kotlinx.dataframe.columns.ValueColumn
 import org.jetbrains.kotlinx.dataframe.columns.toColumnsSetOf
+import org.jetbrains.kotlinx.dataframe.documentation.UnifyingNumbers
 import org.jetbrains.kotlinx.dataframe.impl.DataFrameReceiver
 import org.jetbrains.kotlinx.dataframe.impl.DataRowImpl
+import org.jetbrains.kotlinx.dataframe.impl.api.createConverter
 import org.jetbrains.kotlinx.dataframe.impl.asList
 import org.jetbrains.kotlinx.dataframe.impl.guessValueType
+import org.jetbrains.kotlinx.dataframe.impl.isNothing
 import org.jetbrains.kotlinx.dataframe.impl.replaceGenericTypeParametersWithUpperbound
 import org.jetbrains.kotlinx.dataframe.index
 import org.jetbrains.kotlinx.dataframe.nrow
@@ -42,7 +45,9 @@ import org.jetbrains.kotlinx.dataframe.util.CREATE_COLUMN
 import org.jetbrains.kotlinx.dataframe.util.GUESS_COLUMN_TYPE
 import kotlin.reflect.KClass
 import kotlin.reflect.KType
+import kotlin.reflect.full.isSubtypeOf
 import kotlin.reflect.full.withNullability
+import kotlin.reflect.typeOf
 
 // region create DataColumn
 
@@ -193,6 +198,9 @@ internal fun Array<out String>.toNumberColumns() = toColumnsSetOf<Number>()
  *   Note: this parameter is ignored if another [Collection] is present in the values.
  * @param allColsMakesColGroup if `true`, then, if all values are non-null same-sized columns,
  *   a column group will be created instead of a [DataColumn][DataColumn]`<`[AnyCol][AnyCol]`>`.
+ * @param unifyNumbers if `true`, then all numbers encountered in [values] will be converted to the smallest possible
+ *   number-type that can hold all the values lossless. Unsigned numbers are not supported. See [UnifyingNumbers].
+ *   For example, if the values are `[1, 2f, 3.0]`, then all values will be converted to [Double].
  */
 @PublishedApi
 internal fun <T> createColumnGuessingType(
@@ -202,6 +210,7 @@ internal fun <T> createColumnGuessingType(
     nullable: Boolean? = null,
     listifyValues: Boolean = false,
     allColsMakesColGroup: Boolean = false,
+    unifyNumbers: Boolean = false,
 ): DataColumn<T> =
     createColumnGuessingType(
         name = "",
@@ -211,6 +220,7 @@ internal fun <T> createColumnGuessingType(
         nullable = nullable,
         listifyValues = listifyValues,
         allColsMakesColGroup = allColsMakesColGroup,
+        unifyNumbers = unifyNumbers,
     )
 
 /**
@@ -226,6 +236,7 @@ internal fun <T> createColumnGuessingType(
     nullable: Boolean? = null,
     listifyValues: Boolean = false,
     allColsMakesColGroup: Boolean = false,
+    unifyNumbers: Boolean = false,
 ): DataColumn<T> {
     val type = when (suggestedType) {
         is TypeSuggestion.Infer, is TypeSuggestion.InferWithUpperbound ->
@@ -234,11 +245,23 @@ internal fun <T> createColumnGuessingType(
                 upperBound = (suggestedType as? TypeSuggestion.InferWithUpperbound)?.upperbound,
                 listifyValues = listifyValues,
                 allColsMakesRow = allColsMakesColGroup,
+                unifyNumbers = unifyNumbers,
             )
 
         is TypeSuggestion.Use -> suggestedType.type
     }
 
+    // only needs to be used when unifyNumbers == true
+    @Suppress("UNCHECKED_CAST")
+    fun getSafeNumberConverter(targetType: KType): (Any?) -> Any? {
+        val converter = createConverter(
+            from = typeOf<Number>(),
+            to = targetType,
+        ) as (Number) -> Number?
+
+        return { value -> if (value != null && value is Number) converter(value) else value }
+    }
+
     return when (type.classifier!! as KClass<*>) {
         // guessValueType can only return DataRow if all values are `AnyRow?`
         // or allColsMakesColGroup == true, and all values are `AnyCol`
@@ -269,18 +292,29 @@ internal fun <T> createColumnGuessingType(
         List::class -> {
             val nullable = type.isMarkedNullable
             var isListOfRows: Boolean? = null
-            val lists = values.map {
-                when (it) {
+            val subType = type.arguments.first().type!! // List<T> -> T
+
+            val needsNumberConversion = unifyNumbers &&
+                subType.isSubtypeOf(typeOf<Number?>()) &&
+                !subType.isNothing
+            val numberConverter: (Any?) -> Any? by lazy { getSafeNumberConverter(subType) }
+
+            val lists = values.map { value ->
+                when (value) {
                     null -> if (nullable) null else emptyList()
 
                     is List<*> -> {
-                        if (isListOfRows != false && it.isNotEmpty()) isListOfRows = it.all { it is AnyRow }
-                        it
+                        if (isListOfRows != false && value.isNotEmpty()) isListOfRows = value.all { it is AnyRow }
+
+                        if (needsNumberConversion) value.map(numberConverter) else value
                     }
 
                     else -> { // if !detectType and suggestedType is a list, we wrap the values in lists
-                        if (isListOfRows != false) isListOfRows = it is AnyRow
-                        listOf(it)
+                        if (isListOfRows != false) isListOfRows = value is AnyRow
+
+                        listOf(
+                            if (needsNumberConversion) numberConverter(value) else value,
+                        )
                     }
                 }
             }
@@ -303,10 +337,15 @@ internal fun <T> createColumnGuessingType(
             }
         }
 
-        else ->
+        else -> {
+            val needsNumberConversion = unifyNumbers &&
+                type.isSubtypeOf(typeOf<Number?>()) &&
+                !type.isNothing
+            val numberConverter by lazy { getSafeNumberConverter(type) }
+
             DataColumn.createValueColumn(
                 name = name,
-                values = values.asList(),
+                values = if (needsNumberConversion) values.map(numberConverter) as List<T> else values.asList(),
                 type = if (nullable != null) type.withNullability(nullable) else type,
                 infer = when {
                     // even though an exact type is suggested,
@@ -318,6 +357,7 @@ internal fun <T> createColumnGuessingType(
                 },
                 defaultValue = defaultValue,
             )
+        }
     }
 }
 
@@ -332,6 +372,7 @@ internal fun <T> createColumn(values: Iterable<T>, suggestedType: KType, guessTy
         values = values,
         suggestedType = TypeSuggestion.create(suggestedType, guessType),
         allColsMakesColGroup = true,
+        unifyNumbers = false,
     )
 
 /** Just for binary compatibility, since it's @PublishedApi. */
@@ -355,4 +396,48 @@ internal fun <T> guessColumnType(
         allColsMakesColGroup = false,
     )
 
+/** Just for binary compatibility, since it's @PublishedApi. */
+@Deprecated(GUESS_COLUMN_TYPE, level = DeprecationLevel.HIDDEN)
+@PublishedApi
+internal fun <T> createColumnGuessingType(
+    values: Iterable<T>,
+    suggestedType: TypeSuggestion = TypeSuggestion.Infer,
+    defaultValue: T? = null,
+    nullable: Boolean? = null,
+    listifyValues: Boolean = false,
+    allColsMakesColGroup: Boolean = false,
+): DataColumn<T> =
+    createColumnGuessingType(
+        values = values,
+        suggestedType = suggestedType,
+        defaultValue = defaultValue,
+        nullable = nullable,
+        listifyValues = listifyValues,
+        allColsMakesColGroup = allColsMakesColGroup,
+        unifyNumbers = false,
+    )
+
+/** Just for binary compatibility, since it's @PublishedApi. */
+@Deprecated(GUESS_COLUMN_TYPE, level = DeprecationLevel.HIDDEN)
+@PublishedApi
+internal fun <T> createColumnGuessingType(
+    name: String,
+    values: Iterable<T>,
+    suggestedType: TypeSuggestion = TypeSuggestion.Infer,
+    defaultValue: T? = null,
+    nullable: Boolean? = null,
+    listifyValues: Boolean = false,
+    allColsMakesColGroup: Boolean = false,
+): DataColumn<T> =
+    createColumnGuessingType(
+        name = name,
+        values = values,
+        suggestedType = suggestedType,
+        defaultValue = defaultValue,
+        nullable = nullable,
+        listifyValues = listifyValues,
+        allColsMakesColGroup = allColsMakesColGroup,
+        unifyNumbers = false,
+    )
+
 // endregion
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/io/readJson.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/io/readJson.kt
index 6a1547dcb9..e47f176d32 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/io/readJson.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/impl/io/readJson.kt
@@ -36,6 +36,7 @@ import org.jetbrains.kotlinx.dataframe.api.toDataFrame
 import org.jetbrains.kotlinx.dataframe.columns.ColumnGroup
 import org.jetbrains.kotlinx.dataframe.columns.FrameColumn
 import org.jetbrains.kotlinx.dataframe.columns.TypeSuggestion
+import org.jetbrains.kotlinx.dataframe.documentation.UnifyingNumbers
 import org.jetbrains.kotlinx.dataframe.impl.ColumnNameGenerator
 import org.jetbrains.kotlinx.dataframe.impl.DataCollectorBase
 import org.jetbrains.kotlinx.dataframe.impl.api.chunkedImpl
@@ -78,8 +79,9 @@ internal interface AnyKeyValueProperty : KeyValueProperty<Any?> {
     override val value: Any?
 }
 
-internal fun readJson(
+internal fun readJsonImpl(
     parsed: Any?,
+    unifyNumbers: Boolean,
     header: List<String>,
     keyValuePaths: List<JsonPath> = emptyList(),
     typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
@@ -89,12 +91,14 @@ internal fun readJson(
             when (parsed) {
                 is JsonArray -> fromJsonListArrayAndValueColumns(
                     records = parsed,
+                    unifyNumbers = unifyNumbers,
                     header = header,
                     keyValuePaths = keyValuePaths,
                 )
 
                 else -> fromJsonListArrayAndValueColumns(
                     records = listOf(parsed),
+                    unifyNumbers = unifyNumbers,
                     keyValuePaths = keyValuePaths,
                 )
             }
@@ -104,12 +108,14 @@ internal fun readJson(
             when (parsed) {
                 is JsonArray -> fromJsonListAnyColumns(
                     records = parsed,
+                    unifyNumbers = unifyNumbers,
                     header = header,
                     keyValuePaths = keyValuePaths,
                 )
 
                 else -> fromJsonListAnyColumns(
                     records = listOf(parsed),
+                    unifyNumbers = unifyNumbers,
                     keyValuePaths = keyValuePaths,
                 )
             }
@@ -123,6 +129,7 @@ internal fun readJson(
  * A.k.a. [TypeClashTactic.ANY_COLUMNS].
  *
  * @param records List of json elements to be converted to a [DataFrame].
+ * @param unifyNumbers Whether to [unify the numbers that are read][UnifyingNumbers].
  * @param keyValuePaths List of [JsonPath]s where instead of a [ColumnGroup], a [FrameColumn]<[KeyValueProperty]>
  *     will be created.
  * @param header Optional list of column names. If given, [records] will be read like an object with [header] being the keys.
@@ -130,6 +137,7 @@ internal fun readJson(
  */
 internal fun fromJsonListAnyColumns(
     records: List<*>,
+    unifyNumbers: Boolean,
     keyValuePaths: List<JsonPath> = emptyList(),
     header: List<String> = emptyList(),
     jsonPath: JsonPath = JsonPath(),
@@ -185,6 +193,7 @@ internal fun fromJsonListAnyColumns(
                         val parsed =
                             fromJsonListAnyColumns(
                                 records = listOf(v),
+                                unifyNumbers = unifyNumbers,
                                 keyValuePaths = keyValuePaths,
                                 jsonPath = jsonPath.replaceLastWildcardWithIndex(i),
                             )
@@ -200,6 +209,7 @@ internal fun fromJsonListAnyColumns(
                     is JsonArray -> {
                         val parsed = fromJsonListAnyColumns(
                             records = v,
+                            unifyNumbers = unifyNumbers,
                             keyValuePaths = keyValuePaths,
                             jsonPath = jsonPath.replaceLastWildcardWithIndex(i).appendArrayWithWildcard(),
                         )
@@ -229,10 +239,10 @@ internal fun fromJsonListAnyColumns(
 
                             v.longOrNull != null -> collector.add(v.long)
 
-                            v.doubleOrNull != null -> collector.add(v.double)
-
                             v.floatOrNull != null -> collector.add(v.float)
 
+                            v.doubleOrNull != null -> collector.add(v.double)
+
                             else -> error("Malformed JSON element ${v::class}: $v")
                         }
                     }
@@ -240,7 +250,7 @@ internal fun fromJsonListAnyColumns(
                     else -> collector.add(v)
                 }
             }
-            val column = collector.toColumn(VALUE_COLUMN_NAME)
+            val column = createColumnGuessingType(VALUE_COLUMN_NAME, collector.values, unifyNumbers = unifyNumbers)
             val res = if (nanIndices.isNotEmpty()) {
                 fun <C> DataColumn<C>.updateNaNs(nanValue: C): DataColumn<C> {
                     var j = 0
@@ -281,6 +291,7 @@ internal fun fromJsonListAnyColumns(
             }
             val parsed = fromJsonListAnyColumns(
                 records = values,
+                unifyNumbers = unifyNumbers,
                 keyValuePaths = keyValuePaths,
                 jsonPath = jsonPath.appendArrayWithWildcard(),
             )
@@ -320,6 +331,7 @@ internal fun fromJsonListAnyColumns(
                         val map = record.mapValues { (key, value) ->
                             val parsed = fromJsonListAnyColumns(
                                 records = listOf(value),
+                                unifyNumbers = unifyNumbers,
                                 keyValuePaths = keyValuePaths,
                                 jsonPath = jsonPath.append(key),
                             )
@@ -330,7 +342,7 @@ internal fun fromJsonListAnyColumns(
                             }
                         }
                         val valueType = map.values.map {
-                            guessValueType(sequenceOf(it))
+                            guessValueType(sequenceOf(it), unifyNumbers = unifyNumbers)
                         }.commonType()
 
                         valueTypes += valueType
@@ -340,6 +352,7 @@ internal fun fromJsonListAnyColumns(
                             createColumnGuessingType(
                                 values = map.values,
                                 suggestedType = TypeSuggestion.Use(valueType),
+                                unifyNumbers = unifyNumbers,
                             ).named(KeyValueProperty<*>::value.name),
                         )
                     }
@@ -393,6 +406,7 @@ internal fun fromJsonListAnyColumns(
 
                 val parsed = fromJsonListAnyColumns(
                     records = values,
+                    unifyNumbers = unifyNumbers,
                     keyValuePaths = keyValuePaths,
                     jsonPath = jsonPath.append(colName),
                 )
@@ -436,6 +450,7 @@ private fun AnyFrame.isSingleUnnamedColumn() = ncol == 1 && getColumn(0) is Unna
  * A.k.a. [TypeClashTactic.ARRAY_AND_VALUE_COLUMNS].
  *
  * @param records List of json elements to be converted to a [DataFrame].
+ * @param unifyNumbers Whether to [unify the numbers that are read][UnifyingNumbers].
  * @param keyValuePaths List of [JsonPath]s where instead of a [ColumnGroup], a [FrameColumn]<[KeyValueProperty]>
  *     will be created.
  * @param header Optional list of column names. If given, [records] will be read like an object with [header] being the keys.
@@ -443,6 +458,7 @@ private fun AnyFrame.isSingleUnnamedColumn() = ncol == 1 && getColumn(0) is Unna
  */
 internal fun fromJsonListArrayAndValueColumns(
     records: List<*>,
+    unifyNumbers: Boolean,
     keyValuePaths: List<JsonPath> = emptyList(),
     header: List<String> = emptyList(),
     jsonPath: JsonPath = JsonPath(),
@@ -503,6 +519,7 @@ internal fun fromJsonListArrayAndValueColumns(
                         val map = record.mapValues { (key, value) ->
                             val parsed = fromJsonListArrayAndValueColumns(
                                 records = listOf(value),
+                                unifyNumbers = unifyNumbers,
                                 keyValuePaths = keyValuePaths,
                                 jsonPath = jsonPath.append(key),
                             )
@@ -514,7 +531,7 @@ internal fun fromJsonListArrayAndValueColumns(
                         }
                         val valueType =
                             map.values
-                                .map { guessValueType(sequenceOf(it)) }
+                                .map { guessValueType(sequenceOf(it), unifyNumbers = unifyNumbers) }
                                 .commonType()
 
                         dataFrameOf(
@@ -522,6 +539,7 @@ internal fun fromJsonListArrayAndValueColumns(
                             createColumnGuessingType(
                                 values = map.values,
                                 suggestedType = TypeSuggestion.Use(valueType),
+                                unifyNumbers = unifyNumbers,
                             ).named(KeyValueProperty<*>::value.name),
                         )
                     }
@@ -576,10 +594,10 @@ internal fun fromJsonListArrayAndValueColumns(
 
                                         v.longOrNull != null -> collector.add(v.long)
 
-                                        v.doubleOrNull != null -> collector.add(v.double)
-
                                         v.floatOrNull != null -> collector.add(v.float)
 
+                                        v.doubleOrNull != null -> collector.add(v.double)
+
                                         else -> error("Malformed JSON element ${v::class}: $v")
                                     }
                                 }
@@ -587,7 +605,7 @@ internal fun fromJsonListArrayAndValueColumns(
                                 else -> collector.add(v)
                             }
                         }
-                        val column = collector.toColumn(colName)
+                        val column = createColumnGuessingType(colName, collector.values, unifyNumbers = unifyNumbers)
                         val res = if (nanIndices.isNotEmpty()) {
                             fun <C> DataColumn<C>.updateNaNs(nanValue: C): DataColumn<C> {
                                 var j = 0
@@ -624,6 +642,7 @@ internal fun fromJsonListArrayAndValueColumns(
                         }
                         val parsed = fromJsonListArrayAndValueColumns(
                             records = values,
+                            unifyNumbers = unifyNumbers,
                             keyValuePaths = keyValuePaths,
                             jsonPath = jsonPath.appendArrayWithWildcard(),
                         )
@@ -661,6 +680,7 @@ internal fun fromJsonListArrayAndValueColumns(
 
                         val parsed = fromJsonListArrayAndValueColumns(
                             records = values,
+                            unifyNumbers = unifyNumbers,
                             keyValuePaths = keyValuePaths,
                             jsonPath = jsonPath.append(colName),
                         )
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/json.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/json.kt
index 54b4a799c4..eb5c1690f3 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/json.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/io/json.kt
@@ -19,13 +19,15 @@ import org.jetbrains.kotlinx.dataframe.codeGen.DefaultReadDfMethod
 import org.jetbrains.kotlinx.dataframe.codeGen.DefaultReadJsonMethod
 import org.jetbrains.kotlinx.dataframe.columns.ColumnGroup
 import org.jetbrains.kotlinx.dataframe.columns.FrameColumn
+import org.jetbrains.kotlinx.dataframe.documentation.UnifyingNumbers
 import org.jetbrains.kotlinx.dataframe.impl.io.encodeDataFrameWithMetadata
 import org.jetbrains.kotlinx.dataframe.impl.io.encodeFrame
 import org.jetbrains.kotlinx.dataframe.impl.io.encodeRow
-import org.jetbrains.kotlinx.dataframe.impl.io.readJson
+import org.jetbrains.kotlinx.dataframe.impl.io.readJsonImpl
 import org.jetbrains.kotlinx.dataframe.io.JSON.TypeClashTactic
 import org.jetbrains.kotlinx.dataframe.io.JSON.TypeClashTactic.ANY_COLUMNS
 import org.jetbrains.kotlinx.dataframe.io.JSON.TypeClashTactic.ARRAY_AND_VALUE_COLUMNS
+import org.jetbrains.kotlinx.dataframe.util.READ_JSON
 import java.io.File
 import java.io.InputStream
 import java.net.URL
@@ -34,13 +36,22 @@ import kotlin.reflect.typeOf
 public class JSON(
     private val typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
     private val keyValuePaths: List<JsonPath> = emptyList(),
+    private val unifyNumbers: Boolean = true,
 ) : SupportedDataFrameFormat {
+
+    @Deprecated(READ_JSON, level = DeprecationLevel.HIDDEN)
+    public constructor(
+        typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
+        keyValuePaths: List<JsonPath> = emptyList(),
+    ) : this(typeClashTactic, keyValuePaths, true)
+
     override fun readDataFrame(stream: InputStream, header: List<String>): AnyFrame =
         DataFrame.readJson(
             stream = stream,
             header = header,
             typeClashTactic = typeClashTactic,
             keyValuePaths = keyValuePaths,
+            unifyNumbers = unifyNumbers,
         )
 
     override fun readDataFrame(file: File, header: List<String>): AnyFrame =
@@ -49,6 +60,7 @@ public class JSON(
             header = header,
             typeClashTactic = typeClashTactic,
             keyValuePaths = keyValuePaths,
+            unifyNumbers = unifyNumbers,
         )
 
     override fun acceptsExtension(ext: String): Boolean = ext == "json"
@@ -74,6 +86,11 @@ public class JSON(
                     "typeClashTactic",
                     typeOf<TypeClashTactic>(),
                     "org.jetbrains.kotlinx.dataframe.io.JSON.TypeClashTactic.${typeClashTactic.name}",
+                )
+                .add(
+                    "unifyNumbers",
+                    typeOf<Boolean>(),
+                    unifyNumbers.toString(),
                 ),
         )
 
@@ -127,6 +144,7 @@ internal const val VALUE_COLUMN_NAME: String = "value"
  *     will be created.
  * @param typeClashTactic How to handle type clashes when reading a JSON file.
  * @param header Optional list of column names. If given, the file will be read like an object with [header] being the keys.
+ * @param unifyNumbers Whether to [unify the numbers that are read][UnifyingNumbers]. `true` by default.
  * @return [DataFrame] from the given [file].
  */
 public fun DataFrame.Companion.readJson(
@@ -134,7 +152,8 @@ public fun DataFrame.Companion.readJson(
     header: List<String> = emptyList(),
     keyValuePaths: List<JsonPath> = emptyList(),
     typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
-): AnyFrame = readJson(file.toURI().toURL(), header, keyValuePaths, typeClashTactic)
+    unifyNumbers: Boolean = true,
+): AnyFrame = DataFrame.readJson(file.toURI().toURL(), header, keyValuePaths, typeClashTactic, unifyNumbers)
 
 /**
  * @param file Where to fetch the Json as [InputStream] to be converted to a [DataRow].
@@ -142,6 +161,7 @@ public fun DataFrame.Companion.readJson(
  *     will be created.
  * @param typeClashTactic How to handle type clashes when reading a JSON file.
  * @param header Optional list of column names. If given, the file will be read like an object with [header] being the keys.
+ * @param unifyNumbers Whether to [unify the numbers that are read][UnifyingNumbers]. `true` by default.
  * @return [DataRow] from the given [file].
  */
 public fun DataRow.Companion.readJson(
@@ -149,7 +169,8 @@ public fun DataRow.Companion.readJson(
     header: List<String> = emptyList(),
     keyValuePaths: List<JsonPath> = emptyList(),
     typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
-): AnyRow = DataFrame.readJson(file, header, keyValuePaths, typeClashTactic).single()
+    unifyNumbers: Boolean = true,
+): AnyRow = DataFrame.readJson(file, header, keyValuePaths, typeClashTactic, unifyNumbers).single()
 
 /**
  * @param path URL or file path from where to fetch the Json as [InputStream] to be converted to a [DataFrame].
@@ -157,6 +178,7 @@ public fun DataRow.Companion.readJson(
  *     will be created.
  * @param typeClashTactic How to handle type clashes when reading a JSON file.
  * @param header Optional list of column names. If given, the stream will be read like an object with [header] being the keys.
+ * @param unifyNumbers Whether to [unify the numbers that are read][UnifyingNumbers]. `true` by default.
  * @return [DataFrame] from the given [path].
  */
 @OptInRefine
@@ -166,7 +188,8 @@ public fun DataFrame.Companion.readJson(
     header: List<String> = emptyList(),
     keyValuePaths: List<JsonPath> = emptyList(),
     typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
-): AnyFrame = readJson(asUrl(path), header, keyValuePaths, typeClashTactic)
+    unifyNumbers: Boolean = true,
+): AnyFrame = DataFrame.readJson(asUrl(path), header, keyValuePaths, typeClashTactic, unifyNumbers)
 
 /**
  * @param path URL or file path from where to fetch the Json as [InputStream] to be converted to a [DataRow].
@@ -174,6 +197,7 @@ public fun DataFrame.Companion.readJson(
  *     will be created.
  * @param typeClashTactic How to handle type clashes when reading a JSON file.
  * @param header Optional list of column names. If given, the stream will be read like an object with [header] being the keys.
+ * @param unifyNumbers Whether to [unify the numbers that are read][UnifyingNumbers]. `true` by default.
  * @return [DataRow] from the given [path].
  */
 public fun DataRow.Companion.readJson(
@@ -181,7 +205,8 @@ public fun DataRow.Companion.readJson(
     header: List<String> = emptyList(),
     keyValuePaths: List<JsonPath> = emptyList(),
     typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
-): AnyRow = DataFrame.readJson(path, header, keyValuePaths, typeClashTactic).single()
+    unifyNumbers: Boolean = true,
+): AnyRow = DataFrame.readJson(path, header, keyValuePaths, typeClashTactic, unifyNumbers).single()
 
 /**
  * @param url Where to fetch the Json as [InputStream] to be converted to a [DataFrame].
@@ -189,6 +214,7 @@ public fun DataRow.Companion.readJson(
  *     will be created.
  * @param typeClashTactic How to handle type clashes when reading a JSON file.
  * @param header Optional list of column names. If given, the stream will be read like an object with [header] being the keys.
+ * @param unifyNumbers Whether to [unify the numbers that are read][UnifyingNumbers]. `true` by default.
  * @return [DataFrame] from the given [url].
  */
 public fun DataFrame.Companion.readJson(
@@ -196,7 +222,8 @@ public fun DataFrame.Companion.readJson(
     header: List<String> = emptyList(),
     keyValuePaths: List<JsonPath> = emptyList(),
     typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
-): AnyFrame = catchHttpResponse(url) { readJson(it, header, keyValuePaths, typeClashTactic) }
+    unifyNumbers: Boolean = true,
+): AnyFrame = catchHttpResponse(url) { DataFrame.readJson(it, header, keyValuePaths, typeClashTactic, unifyNumbers) }
 
 /**
  * @param url Where to fetch the Json as [InputStream] to be converted to a [DataRow].
@@ -204,6 +231,7 @@ public fun DataFrame.Companion.readJson(
  *     will be created.
  * @param typeClashTactic How to handle type clashes when reading a JSON file.
  * @param header Optional list of column names. If given, the stream will be read like an object with [header] being the keys.
+ * @param unifyNumbers Whether to [unify the numbers that are read][UnifyingNumbers]. `true` by default.
  * @return [DataRow] from the given [url].
  */
 public fun DataRow.Companion.readJson(
@@ -211,7 +239,8 @@ public fun DataRow.Companion.readJson(
     header: List<String> = emptyList(),
     keyValuePaths: List<JsonPath> = emptyList(),
     typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
-): AnyRow = DataFrame.readJson(url, header, keyValuePaths, typeClashTactic).single()
+    unifyNumbers: Boolean = true,
+): AnyRow = DataFrame.readJson(url, header, keyValuePaths, typeClashTactic, unifyNumbers).single()
 
 /**
  * @param stream Json as [InputStream] to be converted to a [DataFrame].
@@ -219,6 +248,7 @@ public fun DataRow.Companion.readJson(
  *     will be created.
  * @param typeClashTactic How to handle type clashes when reading a JSON file.
  * @param header Optional list of column names. If given, [stream] will be read like an object with [header] being the keys.
+ * @param unifyNumbers Whether to [unify the numbers that are read][UnifyingNumbers]. `true` by default.
  * @return [DataFrame] from the given [stream].
  */
 @OptIn(ExperimentalSerializationApi::class)
@@ -227,7 +257,9 @@ public fun DataFrame.Companion.readJson(
     header: List<String> = emptyList(),
     keyValuePaths: List<JsonPath> = emptyList(),
     typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
-): AnyFrame = readJson(Json.decodeFromStream<JsonElement>(stream), header, keyValuePaths, typeClashTactic)
+    unifyNumbers: Boolean = true,
+): AnyFrame =
+    readJsonImpl(Json.decodeFromStream<JsonElement>(stream), unifyNumbers, header, keyValuePaths, typeClashTactic)
 
 /**
  * @param stream Json as [InputStream] to be converted to a [DataRow].
@@ -235,6 +267,7 @@ public fun DataFrame.Companion.readJson(
  *     will be created.
  * @param typeClashTactic How to handle type clashes when reading a JSON file.
  * @param header Optional list of column names. If given, [stream] will be read like an object with [header] being the keys.
+ * @param unifyNumbers Whether to [unify the numbers that are read][UnifyingNumbers]. `true` by default.
  * @return [DataRow] from the given [stream].
  */
 public fun DataRow.Companion.readJson(
@@ -242,7 +275,8 @@ public fun DataRow.Companion.readJson(
     header: List<String> = emptyList(),
     keyValuePaths: List<JsonPath> = emptyList(),
     typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
-): AnyRow = DataFrame.readJson(stream, header, keyValuePaths, typeClashTactic).single()
+    unifyNumbers: Boolean = true,
+): AnyRow = DataFrame.readJson(stream, header, keyValuePaths, typeClashTactic, unifyNumbers).single()
 
 /**
  * @param text Json as [String] to be converted to a [DataFrame].
@@ -250,6 +284,7 @@ public fun DataRow.Companion.readJson(
  *     will be created.
  * @param typeClashTactic How to handle type clashes when reading a JSON file.
  * @param header Optional list of column names. If given, [text] will be read like an object with [header] being the keys.
+ * @param unifyNumbers Whether to [unify the numbers that are read][UnifyingNumbers]. `true` by default.
  * @return [DataFrame] from the given [text].
  */
 @Refine
@@ -259,7 +294,8 @@ public fun DataFrame.Companion.readJsonStr(
     header: List<String> = emptyList(),
     keyValuePaths: List<JsonPath> = emptyList(),
     typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
-): AnyFrame = readJson(Json.parseToJsonElement(text), header, keyValuePaths, typeClashTactic)
+    unifyNumbers: Boolean = true,
+): AnyFrame = readJsonImpl(Json.parseToJsonElement(text), unifyNumbers, header, keyValuePaths, typeClashTactic)
 
 /**
  * @param text Json as [String] to be converted to a [DataRow].
@@ -267,6 +303,7 @@ public fun DataFrame.Companion.readJsonStr(
  *     will be created.
  * @param typeClashTactic How to handle type clashes when reading a JSON file.
  * @param header Optional list of column names. If given, [text] will be read like an object with [header] being the keys.
+ * @param unifyNumbers Whether to [unify the numbers that are read][UnifyingNumbers]. `true` by default.
  * @return [DataRow] from the given [text].
  */
 @Refine
@@ -276,7 +313,8 @@ public fun DataRow.Companion.readJsonStr(
     header: List<String> = emptyList(),
     keyValuePaths: List<JsonPath> = emptyList(),
     typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
-): AnyRow = DataFrame.readJsonStr(text, header, keyValuePaths, typeClashTactic).single()
+    unifyNumbers: Boolean = true,
+): AnyRow = DataFrame.readJsonStr(text, header, keyValuePaths, typeClashTactic, unifyNumbers).single()
 
 public fun AnyFrame.toJson(prettyPrint: Boolean = false): String {
     val json = Json {
@@ -296,7 +334,8 @@ public fun AnyFrame.toJson(prettyPrint: Boolean = false): String {
  * If null, all rows are included.
  * Applied for each frame column recursively
  * @param prettyPrint Specifies whether the output JSON should be formatted with indentation and line breaks.
- * @param imageEncodingOptions The options for encoding images. The default is null, which indicates that the image is not encoded as Base64.
+ * @param customEncoders The options for encoding things like images.
+ *   The default is empty list, which indicates that the image is not encoded as Base64.
  *
  * @return The DataFrame converted to a JSON string with metadata.
  */
@@ -393,3 +432,79 @@ public fun AnyRow.writeJson(path: String, prettyPrint: Boolean = false) {
 public fun AnyRow.writeJson(writer: Appendable, prettyPrint: Boolean = false) {
     writer.append(toJson(prettyPrint))
 }
+
+// region deprecations
+
+/** Here for binary compatibility. */
+@Deprecated(message = READ_JSON, level = DeprecationLevel.HIDDEN)
+public fun DataFrame.Companion.readJson(
+    file: File,
+    header: List<String> = emptyList(),
+    keyValuePaths: List<JsonPath> = emptyList(),
+    typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
+): AnyFrame = DataFrame.readJson(file, header, keyValuePaths, typeClashTactic, true)
+
+/** Here for binary compatibility. */
+@Deprecated(message = READ_JSON, level = DeprecationLevel.HIDDEN)
+public fun DataRow.Companion.readJson(
+    file: File,
+    header: List<String> = emptyList(),
+    keyValuePaths: List<JsonPath> = emptyList(),
+    typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
+): AnyRow = DataRow.readJson(file, header, keyValuePaths, typeClashTactic, true)
+
+/** Here for binary compatibility. */
+@Deprecated(message = READ_JSON, level = DeprecationLevel.HIDDEN)
+public fun DataFrame.Companion.readJson(
+    stream: InputStream,
+    header: List<String> = emptyList(),
+    keyValuePaths: List<JsonPath> = emptyList(),
+    typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
+): AnyFrame = DataFrame.readJson(stream, header, keyValuePaths, typeClashTactic, true)
+
+/** Here for binary compatibility. */
+@Deprecated(message = READ_JSON, level = DeprecationLevel.HIDDEN)
+public fun DataRow.Companion.readJson(
+    stream: InputStream,
+    header: List<String> = emptyList(),
+    keyValuePaths: List<JsonPath> = emptyList(),
+    typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
+): AnyRow = DataRow.readJson(stream, header, keyValuePaths, typeClashTactic, true)
+
+/** Here for binary compatibility. */
+@Deprecated(message = READ_JSON, level = DeprecationLevel.HIDDEN)
+public fun DataFrame.Companion.readJson(
+    url: URL,
+    header: List<String> = emptyList(),
+    keyValuePaths: List<JsonPath> = emptyList(),
+    typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
+): AnyFrame = DataFrame.readJson(url, header, keyValuePaths, typeClashTactic, true)
+
+/** Here for binary compatibility. */
+@Deprecated(message = READ_JSON, level = DeprecationLevel.HIDDEN)
+public fun DataRow.Companion.readJson(
+    url: URL,
+    header: List<String> = emptyList(),
+    keyValuePaths: List<JsonPath> = emptyList(),
+    typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
+): AnyRow = DataRow.readJson(url, header, keyValuePaths, typeClashTactic, true)
+
+/** Here for binary compatibility. */
+@Deprecated(message = READ_JSON, level = DeprecationLevel.HIDDEN)
+public fun DataFrame.Companion.readJsonStr(
+    @Language("json") text: String,
+    header: List<String> = emptyList(),
+    keyValuePaths: List<JsonPath> = emptyList(),
+    typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
+): AnyFrame = DataFrame.readJsonStr(text, header, keyValuePaths, typeClashTactic, true)
+
+/** Here for binary compatibility. */
+@Deprecated(message = READ_JSON, level = DeprecationLevel.HIDDEN)
+public fun DataRow.Companion.readJsonStr(
+    @Language("json") text: String,
+    header: List<String> = emptyList(),
+    keyValuePaths: List<JsonPath> = emptyList(),
+    typeClashTactic: TypeClashTactic = ARRAY_AND_VALUE_COLUMNS,
+): AnyRow = DataRow.readJsonStr(text, header, keyValuePaths, typeClashTactic, true)
+
+// endregion
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/util/deprecationMessages.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/util/deprecationMessages.kt
index 6539d2a584..11ab7599e5 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/util/deprecationMessages.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/util/deprecationMessages.kt
@@ -60,6 +60,8 @@ internal const val IS_URL_IMPORT = "org.jetbrains.kotlinx.dataframe.io.isUrl"
 internal const val MINUS = "This minus overload will be removed in favor of `remove`. $MESSAGE_0_16"
 internal const val MINUS_REPLACE = "this.remove(columns)"
 
+internal const val READ_JSON = "This function is just here for binary compatibility. $MESSAGE_0_16"
+
 internal const val MOVE_TO_LEFT = "This `moveToLeft` overload will be removed in favor of `moveToStart`. $MESSAGE_0_16"
 internal const val MOVE_TO_LEFT_REPLACE = "this.moveToStart(columns)"
 
diff --git a/core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/api/colsAtAnyDepth.kt b/core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/api/colsAtAnyDepth.kt
index 30160ff9b5..ed9109763d 100644
--- a/core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/api/colsAtAnyDepth.kt
+++ b/core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/api/colsAtAnyDepth.kt
@@ -18,8 +18,6 @@ import org.jetbrains.kotlinx.dataframe.samples.api.city
 import org.jetbrains.kotlinx.dataframe.samples.api.firstName
 import org.jetbrains.kotlinx.dataframe.samples.api.lastName
 import org.jetbrains.kotlinx.dataframe.samples.api.name
-import org.jetbrains.kotlinx.dataframe.samples.api.secondName
-import org.jetbrains.kotlinx.dataframe.samples.api.thirdName
 import org.jetbrains.kotlinx.dataframe.samples.api.weight
 import org.junit.Test
 import kotlin.reflect.typeOf
diff --git a/core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/io/json.kt b/core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/io/json.kt
index 730978aad5..a54a448626 100644
--- a/core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/io/json.kt
+++ b/core/src/test/kotlin/org/jetbrains/kotlinx/dataframe/io/json.kt
@@ -22,6 +22,7 @@ import org.jetbrains.kotlinx.dataframe.DataRow
 import org.jetbrains.kotlinx.dataframe.alsoDebug
 import org.jetbrains.kotlinx.dataframe.api.JsonPath
 import org.jetbrains.kotlinx.dataframe.api.allNulls
+import org.jetbrains.kotlinx.dataframe.api.colsOf
 import org.jetbrains.kotlinx.dataframe.api.columnsCount
 import org.jetbrains.kotlinx.dataframe.api.convert
 import org.jetbrains.kotlinx.dataframe.api.dataFrameOf
@@ -35,7 +36,6 @@ import org.jetbrains.kotlinx.dataframe.columns.ColumnGroup
 import org.jetbrains.kotlinx.dataframe.columns.ColumnKind
 import org.jetbrains.kotlinx.dataframe.columns.FrameColumn
 import org.jetbrains.kotlinx.dataframe.columns.ValueColumn
-import org.jetbrains.kotlinx.dataframe.get
 import org.jetbrains.kotlinx.dataframe.impl.io.SERIALIZATION_VERSION
 import org.jetbrains.kotlinx.dataframe.impl.io.SerializationKeys.COLUMNS
 import org.jetbrains.kotlinx.dataframe.impl.io.SerializationKeys.DATA
@@ -45,8 +45,9 @@ import org.jetbrains.kotlinx.dataframe.impl.io.SerializationKeys.METADATA
 import org.jetbrains.kotlinx.dataframe.impl.io.SerializationKeys.NCOL
 import org.jetbrains.kotlinx.dataframe.impl.io.SerializationKeys.NROW
 import org.jetbrains.kotlinx.dataframe.impl.io.SerializationKeys.VERSION
-import org.jetbrains.kotlinx.dataframe.impl.io.readJson
+import org.jetbrains.kotlinx.dataframe.impl.io.readJsonImpl
 import org.jetbrains.kotlinx.dataframe.impl.nothingType
+import org.jetbrains.kotlinx.dataframe.impl.nullableNothingType
 import org.jetbrains.kotlinx.dataframe.io.JSON.TypeClashTactic.ANY_COLUMNS
 import org.jetbrains.kotlinx.dataframe.io.JSON.TypeClashTactic.ARRAY_AND_VALUE_COLUMNS
 import org.jetbrains.kotlinx.dataframe.parseJsonStr
@@ -54,6 +55,7 @@ import org.jetbrains.kotlinx.dataframe.testJson
 import org.jetbrains.kotlinx.dataframe.type
 import org.jetbrains.kotlinx.dataframe.values
 import org.junit.Test
+import kotlin.Double
 import kotlin.reflect.typeOf
 
 @Suppress("ktlint:standard:argument-list-wrapping")
@@ -122,7 +124,7 @@ class JsonTests {
         df.rowsCount() shouldBe 2
         df["a"].type() shouldBe typeOf<Int>()
         df["b"].type() shouldBe typeOf<Comparable<*>>()
-        df["c"].type() shouldBe typeOf<Double?>()
+        df["c"].type() shouldBe typeOf<Float?>()
     }
 
     @Test
@@ -140,7 +142,7 @@ class JsonTests {
         df.rowsCount() shouldBe 2
         df["a"].type() shouldBe typeOf<Int>()
         df["b"].type() shouldBe typeOf<Comparable<*>>()
-        df["c"].type() shouldBe typeOf<Double?>()
+        df["c"].type() shouldBe typeOf<Float?>()
     }
 
     @Test
@@ -199,7 +201,7 @@ class JsonTests {
         val df = DataFrame.readJsonStr(json).alsoDebug()
         df.columnsCount() shouldBe 1
         df.rowsCount() shouldBe 3
-        df["a"].type() shouldBe typeOf<List<Number>>()
+        df["a"].type() shouldBe typeOf<List<Double>>()
         df[1]["a"] shouldBe emptyList<Int>()
     }
 
@@ -217,7 +219,7 @@ class JsonTests {
         val df = DataFrame.readJsonStr(json, typeClashTactic = ANY_COLUMNS).alsoDebug()
         df.columnsCount() shouldBe 1
         df.rowsCount() shouldBe 3
-        df["a"].type() shouldBe typeOf<List<Number>>()
+        df["a"].type() shouldBe typeOf<List<Double>>()
         df[1]["a"] shouldBe emptyList<Int>()
     }
 
@@ -228,7 +230,7 @@ class JsonTests {
             """
             [
                 {"a":[ {"b":2}, {"c":3} ]},
-                {"a":[ {"b":4}, {"d":5} ]}
+                {"a":[ {"b":4.0}, {"d":5} ]}
             ]
             """.trimIndent()
         val df = DataFrame.readJsonStr(json).alsoDebug()
@@ -238,7 +240,7 @@ class JsonTests {
         group[0].alsoDebug().let {
             it.columnsCount() shouldBe 3
             it.rowsCount() shouldBe 2
-            it["b"].type() shouldBe typeOf<Int?>()
+            it["b"].type() shouldBe typeOf<Double?>()
             it["c"].type() shouldBe typeOf<Int?>()
             it["d"].type() shouldBe typeOf<Int?>()
             it["b"].values.toList() shouldBe listOf(2, null)
@@ -249,7 +251,7 @@ class JsonTests {
         group[1].alsoDebug().let {
             it.columnsCount() shouldBe 3
             it.rowsCount() shouldBe 2
-            it["b"].type() shouldBe typeOf<Int?>()
+            it["b"].type() shouldBe typeOf<Double?>()
             it["c"].type() shouldBe typeOf<Int?>()
             it["d"].type() shouldBe typeOf<Int?>()
             it["b"].values.toList() shouldBe listOf(4, null)
@@ -295,6 +297,31 @@ class JsonTests {
         }
     }
 
+    @Test
+    fun `json and number unification`() {
+        @Language("json")
+        val json =
+            """
+            [
+                {"a":1},
+                {"a":2.0},
+                {"a":3},
+                {"a":4.5}
+            ]
+            """.trimIndent()
+        val df1 = DataFrame.readJsonStr(json, unifyNumbers = true).alsoDebug()
+        df1.columnsCount() shouldBe 1
+        df1.rowsCount() shouldBe 4
+        df1["a"].type() shouldBe typeOf<Double>()
+        df1["a"].values.toList() shouldBe listOf(1.0, 2.0, 3.0, 4.5)
+
+        val df2 = DataFrame.readJsonStr(json, unifyNumbers = false).alsoDebug()
+        df2.columnsCount() shouldBe 1
+        df2.rowsCount() shouldBe 4
+        df2["a"].type() shouldBe typeOf<Number>()
+        df2["a"].values.toList() shouldBe listOf(1, 2.0f, 3, 4.5f)
+    }
+
     @Test
     fun `parse json with nested json array with mixed values`() {
         @Language("json")
@@ -383,7 +410,7 @@ class JsonTests {
         ).alsoDebug("df:")
 
         val res = DataFrame.readJsonStr(df.toJson()).alsoDebug("res:")
-        res shouldBe df
+        res shouldBe df.convert { colsOf<Double?>() }.toFloat()
     }
 
     @Test
@@ -396,21 +423,17 @@ class JsonTests {
 
         val res =
             DataFrame.readJsonStr(df.toJson(), typeClashTactic = ANY_COLUMNS).alsoDebug("res:")
-        res shouldBe df
-    }
-
-    @Test
-    fun `NaN double serialization`() {
-        val df = dataFrameOf("v")(1.1, Double.NaN)
-        df["v"].type() shouldBe typeOf<Double>()
-        DataFrame.readJsonStr(df.toJson()) shouldBe df
+        res shouldBe df.convert { colsOf<Double?>() }.toFloat()
     }
 
     @Test
     fun `NaN double serialization Any`() {
         val df = dataFrameOf("v")(1.1, Double.NaN)
         df["v"].type() shouldBe typeOf<Double>()
-        DataFrame.readJsonStr(df.toJson(), typeClashTactic = ANY_COLUMNS) shouldBe df
+
+        val df2 = DataFrame.readJsonStr(df.toJson(), typeClashTactic = ANY_COLUMNS)
+        df2["v"].type() shouldBe typeOf<Float>()
+        df2 shouldBe df.convert("v").toFloat()
     }
 
     @Test
@@ -583,7 +606,7 @@ class JsonTests {
         val group = df["a"] as ColumnGroup<*>
         group.columnsCount() shouldBe 6
         group["b"].type() shouldBe typeOf<Int?>()
-        group["value"].type() shouldBe typeOf<Double?>()
+        group["value"].type() shouldBe typeOf<Float?>()
         group["value1"].type() shouldBe typeOf<String?>()
         group["array"].type() shouldBe nothingType(nullable = true)
 
@@ -922,7 +945,7 @@ class JsonTests {
 
             it["b"].type() shouldBe typeOf<Any?>()
             it["c"].type() shouldBe typeOf<Int?>()
-            it["d"].type() shouldBe typeOf<Any?>()
+            it["d"].type() shouldBe nullableNothingType
 
             it[0].toMap() shouldBe mapOf("b" to 1, "c" to null, "d" to null)
             it[1].toMap() shouldBe mapOf("b" to listOf(1, 2, 3), "c" to 2, "d" to null)
@@ -1115,7 +1138,7 @@ class JsonTests {
         // https://github.com/Kotlin/kotlinx.serialization/issues/2511
         val json = Json.decodeFromString<JsonElement>("""[jetbrains, jetbrains-youtrack, youtrack, youtrack-api]""")
         shouldThrow<IllegalStateException> {
-            readJson(json, emptyList())
+            readJsonImpl(json, true, emptyList())
         }
     }
 }
diff --git a/docs/StardustDocs/topics/read.md b/docs/StardustDocs/topics/read.md
index 7843c90a63..14082d09f4 100644
--- a/docs/StardustDocs/topics/read.md
+++ b/docs/StardustDocs/topics/read.md
@@ -310,8 +310,9 @@ DataFrame.readJson("https://covid.ourworldindata.org/data/owid-covid-data.json")
 ### Column type inference from JSON
 
 Type inference for JSON is much simpler than for CSV.
-JSON string literals are always supposed to have String type. Number literals
-take different `Number` kinds. Boolean literals are converted to `Boolean`.
+JSON string literals always become a `String`.
+Number literals are converted to a unified `Number` type which will fit all encountered numbers.
+Boolean literals are converted to `Boolean`.
 
 Let's take a look at the following JSON:
 
@@ -355,12 +356,12 @@ The corresponding [`DataFrame`](DataFrame.md) schema is:
 ```text
 A: String
 B: Int
-C: Number
+C: Double
 D: Boolean?
 ```
 
 Column A has `String` type because all values are string literals, no implicit conversion is performed. Column C
-has `Number` type because it's the least common type for `Int` and `Double`.
+has the `Double` type because it's the smallest unified number type for `Int` and `Float`.
 
 ### JSON parsing options
 
@@ -370,8 +371,8 @@ By default, if a type clash occurs when reading JSON, a new column group is crea
 any number of object properties:
 
 "value" will be set to the value of the JSON element if it's a primitive, else it will be `null`.\
-"array" will be set to the array of values if the json element is an array, else it will be `[]`.\
-If the json element is an object, then each property will spread out to its own column in the group, else these columns
+"array" will be set to the array of values if the JSON element is an array, else it will be `[]`.\
+If the JSON element is an object, then each property will spread out to its own column in the group, else these columns
 will be `null`.
 
 In this case `typeClashTactic = JSON.TypeClashTactic.ARRAY_AND_VALUE_COLUMNS`.
diff --git a/plugins/dataframe-gradle-plugin/src/main/kotlin/org/jetbrains/dataframe/gradle/GenerateDataSchemaTask.kt b/plugins/dataframe-gradle-plugin/src/main/kotlin/org/jetbrains/dataframe/gradle/GenerateDataSchemaTask.kt
index 8dbfa3f996..dfec70c339 100644
--- a/plugins/dataframe-gradle-plugin/src/main/kotlin/org/jetbrains/dataframe/gradle/GenerateDataSchemaTask.kt
+++ b/plugins/dataframe-gradle-plugin/src/main/kotlin/org/jetbrains/dataframe/gradle/GenerateDataSchemaTask.kt
@@ -117,7 +117,11 @@ abstract class GenerateDataSchemaTask : DefaultTask() {
 
             val formats = listOf(
                 CsvDeephaven(delimiter = csvOptions.delimiter),
-                JSON(typeClashTactic = jsonOptions.typeClashTactic, keyValuePaths = jsonOptions.keyValuePaths),
+                JSON(
+                    typeClashTactic = jsonOptions.typeClashTactic,
+                    keyValuePaths = jsonOptions.keyValuePaths,
+                    unifyNumbers = jsonOptions.unifyNumbers,
+                ),
                 Excel(),
                 TsvDeephaven(),
                 ArrowFeather(),
diff --git a/plugins/dataframe-gradle-plugin/src/main/kotlin/org/jetbrains/dataframe/gradle/SchemaGeneratorExtension.kt b/plugins/dataframe-gradle-plugin/src/main/kotlin/org/jetbrains/dataframe/gradle/SchemaGeneratorExtension.kt
index b9f3dc9c55..7f402be156 100644
--- a/plugins/dataframe-gradle-plugin/src/main/kotlin/org/jetbrains/dataframe/gradle/SchemaGeneratorExtension.kt
+++ b/plugins/dataframe-gradle-plugin/src/main/kotlin/org/jetbrains/dataframe/gradle/SchemaGeneratorExtension.kt
@@ -129,6 +129,7 @@ data class CsvOptionsDsl(var delimiter: Char = ',') : Serializable
 data class JsonOptionsDsl(
     var typeClashTactic: JSON.TypeClashTactic = JSON.TypeClashTactic.ARRAY_AND_VALUE_COLUMNS,
     var keyValuePaths: List<JsonPath> = emptyList(),
+    var unifyNumbers: Boolean = true,
 ) : Serializable
 
 /**
diff --git a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/read.kt b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/read.kt
index 0b8d99a3d5..53610938f9 100644
--- a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/read.kt
+++ b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/read.kt
@@ -125,18 +125,20 @@ internal class ReadDelimStr : AbstractInterpreter<PluginDataFrameSchema>() {
 internal class ReadJsonStr : AbstractInterpreter<PluginDataFrameSchema>() {
     val Arguments.text: String by arg()
     val Arguments.typeClashTactic: JSON.TypeClashTactic by arg(defaultValue = Present(ARRAY_AND_VALUE_COLUMNS))
+    val Arguments.unifyNumbers: Boolean by arg(defaultValue = Present(true))
 
     override fun Arguments.interpret(): PluginDataFrameSchema {
-        return DataFrame.readJsonStr(text, typeClashTactic = typeClashTactic).schema().toPluginDataFrameSchema()
+        return DataFrame.readJsonStr(text, typeClashTactic = typeClashTactic, unifyNumbers = unifyNumbers).schema().toPluginDataFrameSchema()
     }
 }
 
 internal class DataRowReadJsonStr : AbstractInterpreter<PluginDataFrameSchema>() {
     val Arguments.text: String by arg()
     val Arguments.typeClashTactic: JSON.TypeClashTactic by arg(defaultValue = Present(ARRAY_AND_VALUE_COLUMNS))
+    val Arguments.unifyNumbers: Boolean by arg(defaultValue = Present(true))
 
     override fun Arguments.interpret(): PluginDataFrameSchema {
-        return DataRow.readJsonStr(text, typeClashTactic = typeClashTactic).schema().toPluginDataFrameSchema()
+        return DataRow.readJsonStr(text, typeClashTactic = typeClashTactic, unifyNumbers = unifyNumbers).schema().toPluginDataFrameSchema()
     }
 }
 
diff --git a/tests/src/test/kotlin/org/jetbrains/kotlinx/dataframe/samples/api/Read.kt b/tests/src/test/kotlin/org/jetbrains/kotlinx/dataframe/samples/api/Read.kt
index ffb27ae5fd..d9e38391c2 100644
--- a/tests/src/test/kotlin/org/jetbrains/kotlinx/dataframe/samples/api/Read.kt
+++ b/tests/src/test/kotlin/org/jetbrains/kotlinx/dataframe/samples/api/Read.kt
@@ -62,7 +62,7 @@ class Read {
         val row = DataRow.readJson(file)
         // SampleEnd
         row.columnNames() shouldBe listOf("A", "B", "C", "D")
-        row.columnTypes() shouldBe listOf(typeOf<String>(), typeOf<Int>(), typeOf<Double>(), typeOf<Boolean>())
+        row.columnTypes() shouldBe listOf(typeOf<String>(), typeOf<Int>(), typeOf<Float>(), typeOf<Boolean>())
     }
 
     @Test