diff --git a/jooby-raml/src/main/java/org/jooby/internal/raml/RamlBuilder.java b/jooby-raml/src/main/java/org/jooby/internal/raml/RamlBuilder.java
index 258239266f..246781df66 100644
--- a/jooby-raml/src/main/java/org/jooby/internal/raml/RamlBuilder.java
+++ b/jooby-raml/src/main/java/org/jooby/internal/raml/RamlBuilder.java
@@ -272,7 +272,7 @@ public String build(final List<RouteSpec> routes) {
     Consumer<Type> typeCollector = type -> {
       if (type != Object.class && type != void.class) {
         RamlType.parseAll(type).stream()
-            .filter(t -> t.isObject() || t.isEnum())
+            .filter(t -> t.isCustom())
             .forEach(types::add);
       }
     };
diff --git a/jooby-raml/src/main/java/org/jooby/internal/raml/RamlType.java b/jooby-raml/src/main/java/org/jooby/internal/raml/RamlType.java
index 63d6a2aecf..e4dbb95707 100644
--- a/jooby-raml/src/main/java/org/jooby/internal/raml/RamlType.java
+++ b/jooby-raml/src/main/java/org/jooby/internal/raml/RamlType.java
@@ -32,6 +32,7 @@
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
+import java.util.UUID;
 
 import com.google.common.collect.ImmutableList;
 
@@ -49,6 +50,8 @@ public class RamlType {
 
   private List<String> values;
 
+  private String pattern;
+
   public RamlType(final String type) {
     this.type = type;
   }
@@ -65,6 +68,8 @@ public Map<String, RamlType> properties() {
     return properties;
   }
 
+  public String pattern(){ return pattern; }
+
   @Override
   public boolean equals(final Object obj) {
     if (obj instanceof RamlType) {
@@ -115,6 +120,9 @@ public String toString(int level) {
     if (values != null) {
       buff.append(indent(level)).append("enum: ").append(values.toString()).append("\n");
     }
+    if (pattern != null) {
+      buff.append(indent(level)).append("pattern: ").append(pattern).append("\n");
+    }
     buff.setLength(buff.length() - 1);
     return buff.toString();
   }
@@ -196,6 +204,10 @@ private static RamlType simpleParse(final Type type) {
         enums.add(((Enum) value).name());
       }
       complex.values = enums;
+    } else if (UUID.class.isAssignableFrom(rawType)) {
+      complex = new RamlType("string");
+      complex.name = "uuid";
+      complex.pattern = "^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$";
     } else {
       complex = new RamlType("object");
       complex.name = rawType.getSimpleName();
@@ -282,6 +294,12 @@ private static Class<?> componentType(final Type type) {
     return null;
   }
 
+  public boolean isCustom() {
+    return properties != null ||
+            values != null ||
+            pattern != null;
+  }
+
   public boolean isObject() {
     return properties != null;
   }
diff --git a/jooby-raml/src/test/java/org/jooby/raml/RamlTypeTest.java b/jooby-raml/src/test/java/org/jooby/raml/RamlTypeTest.java
index 117795a1a8..0395cb31c5 100644
--- a/jooby-raml/src/test/java/org/jooby/raml/RamlTypeTest.java
+++ b/jooby-raml/src/test/java/org/jooby/raml/RamlTypeTest.java
@@ -6,6 +6,7 @@
 import java.time.LocalDate;
 import java.util.Date;
 import java.util.Optional;
+import java.util.UUID;
 
 import org.jooby.Upload;
 import org.jooby.internal.raml.RamlType;
@@ -66,6 +67,13 @@ public void object() {
         "      required: false", RamlType.parse(Person.class).toString());
   }
 
+  @Test
+  public void uuid() {
+    assertEquals("uuid:\n" +
+            "  type: string\n" +
+            "  pattern: ^[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}$", RamlType.parse(UUID.class).toString());
+  }
+
   private Type optional(final Class<?> type) {
     return Types.newParameterizedType(Optional.class, type);
   }