diff --git a/CHANGELOG.md b/CHANGELOG.md
index a1d3de3da..bd0dfd903 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -16,6 +16,7 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 - ![API] Refactor cache API [#500](https://github.com/nbbrd/sdmx-dl/issues/500)
 - ![API] Refactor network API [#503](https://github.com/nbbrd/sdmx-dl/issues/503)
 - ![API] Remove dialect API [#505](https://github.com/nbbrd/sdmx-dl/issues/505)
+- ![API] Refactor listeners API [#506](https://github.com/nbbrd/sdmx-dl/issues/506)
 - ![SOURCE] Update ECB endpoint [#495](https://github.com/nbbrd/sdmx-dl/issues/495)
 - ![FORMAT] Refactor file format API [#502](https://github.com/nbbrd/sdmx-dl/issues/502)
 - ![PROVIDER] Move curl backend to an external project
diff --git a/sdmx-dl-api/src/main/java/internal/sdmxdl/NoOpCaching.java b/sdmx-dl-api/src/main/java/internal/sdmxdl/NoOpCaching.java
index 70301efc4..183133367 100644
--- a/sdmx-dl-api/src/main/java/internal/sdmxdl/NoOpCaching.java
+++ b/sdmx-dl-api/src/main/java/internal/sdmxdl/NoOpCaching.java
@@ -1,7 +1,9 @@
 package internal.sdmxdl;
 
 import lombok.NonNull;
-import sdmxdl.ext.SdmxSourceConsumer;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import sdmxdl.ErrorListener;
+import sdmxdl.EventListener;
 import sdmxdl.file.FileCache;
 import sdmxdl.file.SdmxFileSource;
 import sdmxdl.file.spi.FileCaching;
@@ -37,12 +39,12 @@ public int getWebCachingRank() {
     }
 
     @Override
-    public @NonNull FileCache getFileCache(@NonNull SdmxFileSource source, @NonNull SdmxSourceConsumer<? super SdmxFileSource, ? super String> listener) {
+    public @NonNull FileCache getFileCache(@NonNull SdmxFileSource ignoreSource, @Nullable EventListener<? super SdmxFileSource> ignoreEvent, @Nullable ErrorListener<? super SdmxFileSource> ignoreError) {
         return FileCache.noOp();
     }
 
     @Override
-    public @NonNull WebCache getWebCache(@NonNull SdmxWebSource source, @NonNull SdmxSourceConsumer<? super SdmxWebSource, ? super String> listener) {
+    public @NonNull WebCache getWebCache(@NonNull SdmxWebSource ignoreSource, @Nullable EventListener<? super SdmxWebSource> ignoreEvent, @Nullable ErrorListener<? super SdmxWebSource> ignoreError) {
         return WebCache.noOp();
     }
 
diff --git a/sdmx-dl-api/src/main/java/sdmxdl/ErrorListener.java b/sdmx-dl-api/src/main/java/sdmxdl/ErrorListener.java
new file mode 100644
index 000000000..8d8e1b388
--- /dev/null
+++ b/sdmx-dl-api/src/main/java/sdmxdl/ErrorListener.java
@@ -0,0 +1,16 @@
+package sdmxdl;
+
+import lombok.NonNull;
+
+import java.io.IOException;
+import java.util.function.BiConsumer;
+
+@FunctionalInterface
+public interface ErrorListener<S extends SdmxSource> {
+
+    void accept(@NonNull S source, @NonNull Marker marker, @NonNull CharSequence message, @NonNull IOException error);
+
+    default @NonNull BiConsumer<CharSequence, IOException> asBiConsumer(@NonNull S source, @NonNull Marker marker) {
+        return (message, error) -> accept(source, marker, message, error);
+    }
+}
diff --git a/sdmx-dl-api/src/main/java/sdmxdl/EventListener.java b/sdmx-dl-api/src/main/java/sdmxdl/EventListener.java
new file mode 100644
index 000000000..b1b2e6168
--- /dev/null
+++ b/sdmx-dl-api/src/main/java/sdmxdl/EventListener.java
@@ -0,0 +1,15 @@
+package sdmxdl;
+
+import lombok.NonNull;
+
+import java.util.function.Consumer;
+
+@FunctionalInterface
+public interface EventListener<S extends SdmxSource> {
+
+    void accept(@NonNull S source, @NonNull Marker marker, @NonNull CharSequence message);
+
+    default @NonNull Consumer<CharSequence> asConsumer(@NonNull S source, @NonNull Marker marker) {
+        return message -> accept(source, marker, message);
+    }
+}
diff --git a/sdmx-dl-api/src/main/java/sdmxdl/Marker.java b/sdmx-dl-api/src/main/java/sdmxdl/Marker.java
new file mode 100644
index 000000000..f768ebfe7
--- /dev/null
+++ b/sdmx-dl-api/src/main/java/sdmxdl/Marker.java
@@ -0,0 +1,25 @@
+package sdmxdl;
+
+import lombok.AccessLevel;
+import lombok.NonNull;
+import nbbrd.design.RepresentableAsString;
+import nbbrd.design.StaticFactoryMethod;
+
+@RepresentableAsString
+@lombok.AllArgsConstructor(access = AccessLevel.PRIVATE)
+@lombok.EqualsAndHashCode
+public class Marker implements CharSequence {
+
+    @lombok.experimental.Delegate(types = CharSequence.class)
+    private final @NonNull String value;
+
+    @Override
+    public String toString() {
+        return value;
+    }
+
+    @StaticFactoryMethod
+    public static @NonNull Marker parse(@NonNull CharSequence value) {
+        return new Marker(value.toString());
+    }
+}
diff --git a/sdmx-dl-api/src/main/java/sdmxdl/SdmxManager.java b/sdmx-dl-api/src/main/java/sdmxdl/SdmxManager.java
index b83f7b206..aa342d39d 100644
--- a/sdmx-dl-api/src/main/java/sdmxdl/SdmxManager.java
+++ b/sdmx-dl-api/src/main/java/sdmxdl/SdmxManager.java
@@ -19,7 +19,7 @@
 import lombok.NonNull;
 import nbbrd.design.SealedType;
 import nbbrd.design.ThreadSafe;
-import sdmxdl.ext.SdmxSourceConsumer;
+import org.checkerframework.checker.nullness.qual.Nullable;
 import sdmxdl.file.SdmxFileManager;
 import sdmxdl.web.SdmxWebManager;
 
@@ -39,8 +39,7 @@ public abstract class SdmxManager<SOURCE extends SdmxSource> {
 
     public abstract @NonNull LanguagePriorityList getLanguages();
 
-    public abstract @NonNull SdmxSourceConsumer<? super SOURCE, ? super String> getEventListener();
+    public abstract @Nullable EventListener<? super SOURCE> getOnEvent();
 
-    public static final SdmxSourceConsumer<SdmxSource, String> NO_OP_EVENT_LISTENER = (source, t) -> {
-    };
+    public abstract @Nullable ErrorListener<? super SOURCE> getOnError();
 }
diff --git a/sdmx-dl-api/src/main/java/sdmxdl/ext/SdmxSourceBiConsumer.java b/sdmx-dl-api/src/main/java/sdmxdl/ext/SdmxSourceBiConsumer.java
deleted file mode 100644
index 73f2769b7..000000000
--- a/sdmx-dl-api/src/main/java/sdmxdl/ext/SdmxSourceBiConsumer.java
+++ /dev/null
@@ -1,16 +0,0 @@
-package sdmxdl.ext;
-
-import lombok.NonNull;
-import sdmxdl.SdmxSource;
-
-import java.util.function.BiConsumer;
-
-@FunctionalInterface
-public interface SdmxSourceBiConsumer<S extends SdmxSource, T, U> {
-
-    void accept(S source, T t, U u);
-
-    default @NonNull BiConsumer<T, U> asBiConsumer(S source) {
-        return (t, u) -> accept(source, t, u);
-    }
-}
diff --git a/sdmx-dl-api/src/main/java/sdmxdl/ext/SdmxSourceConsumer.java b/sdmx-dl-api/src/main/java/sdmxdl/ext/SdmxSourceConsumer.java
deleted file mode 100644
index 55a181cc5..000000000
--- a/sdmx-dl-api/src/main/java/sdmxdl/ext/SdmxSourceConsumer.java
+++ /dev/null
@@ -1,15 +0,0 @@
-package sdmxdl.ext;
-
-import lombok.NonNull;
-import sdmxdl.SdmxSource;
-
-import java.util.function.BiConsumer;
-import java.util.function.Consumer;
-
-@FunctionalInterface
-public interface SdmxSourceConsumer<S extends SdmxSource, T> extends BiConsumer<S, T> {
-
-    default @NonNull Consumer<T> asConsumer(S source) {
-        return t -> accept(source, t);
-    }
-}
diff --git a/sdmx-dl-api/src/main/java/sdmxdl/file/SdmxFileManager.java b/sdmx-dl-api/src/main/java/sdmxdl/file/SdmxFileManager.java
index 43c23e400..ab43048fc 100644
--- a/sdmx-dl-api/src/main/java/sdmxdl/file/SdmxFileManager.java
+++ b/sdmx-dl-api/src/main/java/sdmxdl/file/SdmxFileManager.java
@@ -21,10 +21,8 @@
 import lombok.AccessLevel;
 import lombok.NonNull;
 import nbbrd.design.StaticFactoryMethod;
-import sdmxdl.Connection;
-import sdmxdl.LanguagePriorityList;
-import sdmxdl.SdmxManager;
-import sdmxdl.ext.SdmxSourceConsumer;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import sdmxdl.*;
 import sdmxdl.file.spi.FileCaching;
 import sdmxdl.file.spi.FileContext;
 import sdmxdl.file.spi.FileReader;
@@ -62,9 +60,9 @@ public class SdmxFileManager extends SdmxManager<SdmxFileSource> {
     @lombok.Builder.Default
     FileCaching caching = FileCaching.noOp();
 
-    @lombok.NonNull
-    @lombok.Builder.Default
-    SdmxSourceConsumer<? super SdmxFileSource, ? super String> eventListener = NO_OP_EVENT_LISTENER;
+    @Nullable EventListener<? super SdmxFileSource> onEvent;
+
+    @Nullable ErrorListener<? super SdmxFileSource> onError;
 
     @lombok.NonNull
     @lombok.Singular
@@ -86,7 +84,8 @@ private FileContext initContext() {
         return FileContext
                 .builder()
                 .languages(languages)
-                .eventListener(eventListener)
+                .onEvent(onEvent)
+                .onError(onError)
                 .caching(caching)
                 .build();
     }
diff --git a/sdmx-dl-api/src/main/java/sdmxdl/file/spi/FileCaching.java b/sdmx-dl-api/src/main/java/sdmxdl/file/spi/FileCaching.java
index b3dc4e779..a40304e8c 100644
--- a/sdmx-dl-api/src/main/java/sdmxdl/file/spi/FileCaching.java
+++ b/sdmx-dl-api/src/main/java/sdmxdl/file/spi/FileCaching.java
@@ -7,7 +7,9 @@
 import nbbrd.service.ServiceDefinition;
 import nbbrd.service.ServiceId;
 import nbbrd.service.ServiceSorter;
-import sdmxdl.ext.SdmxSourceConsumer;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import sdmxdl.ErrorListener;
+import sdmxdl.EventListener;
 import sdmxdl.file.FileCache;
 import sdmxdl.file.SdmxFileSource;
 
@@ -26,14 +28,17 @@ public interface FileCaching {
     @ServiceSorter(reverse = true)
     int getFileCachingRank();
 
-    @NonNull FileCache getFileCache(@NonNull SdmxFileSource source, @NonNull SdmxSourceConsumer<? super SdmxFileSource, ? super String> listener);
+    @NonNull FileCache getFileCache(
+            @NonNull SdmxFileSource source,
+            @Nullable EventListener<? super SdmxFileSource> onEvent,
+            @Nullable ErrorListener<? super SdmxFileSource> onError);
 
     @NonNull Collection<String> getFileCachingProperties();
 
-    int UNKNOWN_FILE_CACHING_RANK = -1;
-
     @StaticFactoryMethod
     static @NonNull FileCaching noOp() {
         return NoOpCaching.INSTANCE;
     }
+
+    int UNKNOWN_FILE_CACHING_RANK = -1;
 }
diff --git a/sdmx-dl-api/src/main/java/sdmxdl/file/spi/FileContext.java b/sdmx-dl-api/src/main/java/sdmxdl/file/spi/FileContext.java
index 81efc30e6..657f2f079 100644
--- a/sdmx-dl-api/src/main/java/sdmxdl/file/spi/FileContext.java
+++ b/sdmx-dl-api/src/main/java/sdmxdl/file/spi/FileContext.java
@@ -1,9 +1,10 @@
 package sdmxdl.file.spi;
 
 import lombok.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import sdmxdl.ErrorListener;
+import sdmxdl.EventListener;
 import sdmxdl.LanguagePriorityList;
-import sdmxdl.SdmxManager;
-import sdmxdl.ext.SdmxSourceConsumer;
 import sdmxdl.file.FileCache;
 import sdmxdl.file.SdmxFileSource;
 
@@ -19,11 +20,11 @@ public class FileContext {
     @lombok.Builder.Default
     FileCaching caching = FileCaching.noOp();
 
-    @lombok.NonNull
-    @lombok.Builder.Default
-    SdmxSourceConsumer<? super SdmxFileSource, ? super String> eventListener = SdmxManager.NO_OP_EVENT_LISTENER;
+    @Nullable EventListener<? super SdmxFileSource> onEvent;
+
+    @Nullable ErrorListener<? super SdmxFileSource> onError;
 
     public @NonNull FileCache getCache(@NonNull SdmxFileSource source) {
-        return getCaching().getFileCache(source, getEventListener());
+        return getCaching().getFileCache(source, getOnEvent(), getOnError());
     }
 }
diff --git a/sdmx-dl-api/src/main/java/sdmxdl/web/SdmxWebManager.java b/sdmx-dl-api/src/main/java/sdmxdl/web/SdmxWebManager.java
index f9279dde2..0864d51fc 100644
--- a/sdmx-dl-api/src/main/java/sdmxdl/web/SdmxWebManager.java
+++ b/sdmx-dl-api/src/main/java/sdmxdl/web/SdmxWebManager.java
@@ -20,11 +20,9 @@
 import lombok.AccessLevel;
 import lombok.NonNull;
 import nbbrd.design.StaticFactoryMethod;
-import sdmxdl.Connection;
-import sdmxdl.LanguagePriorityList;
-import sdmxdl.SdmxManager;
-import sdmxdl.ext.SdmxSourceConsumer;
-import sdmxdl.web.spi.WebCaching;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import sdmxdl.EventListener;
+import sdmxdl.*;
 import sdmxdl.web.spi.*;
 
 import java.io.IOException;
@@ -45,6 +43,8 @@
 @lombok.EqualsAndHashCode(callSuper = false)
 public class SdmxWebManager extends SdmxManager<SdmxWebSource> {
 
+    public static final Marker WEB_MANAGER_MARKER = Marker.parse("WEB_MANAGER");
+
     @StaticFactoryMethod
     public static @NonNull SdmxWebManager ofServiceLoader() {
         return SdmxWebManager
@@ -82,9 +82,9 @@ public class SdmxWebManager extends SdmxManager<SdmxWebSource> {
     @lombok.Builder.Default
     WebCaching caching = WebCaching.noOp();
 
-    @lombok.NonNull
-    @lombok.Builder.Default
-    SdmxSourceConsumer<? super SdmxWebSource, ? super String> eventListener = NO_OP_EVENT_LISTENER;
+    @Nullable EventListener<? super SdmxWebSource> onEvent;
+
+    @Nullable ErrorListener<? super SdmxWebSource> onError;
 
     @lombok.NonNull
     @lombok.Singular
@@ -146,12 +146,12 @@ public MonitorReport getMonitorReport(@NonNull SdmxWebSource source) throws IOEx
     }
 
     private void checkSourceProperties(SdmxWebSource source, WebDriver driver) {
-        if (eventListener != NO_OP_EVENT_LISTENER) {
+        if (onEvent != null) {
             Collection<String> expected = driver.getSupportedProperties();
             Collection<String> found = source.getProperties().keySet();
             String diff = found.stream().filter(item -> !expected.contains(item)).sorted().collect(Collectors.joining(","));
             if (!diff.isEmpty()) {
-                eventListener.accept(source, "Unexpected properties [" + diff + "]");
+                onEvent.accept(source, WEB_MANAGER_MARKER, "Unexpected properties [" + diff + "]");
             }
         }
     }
@@ -180,7 +180,8 @@ private WebContext initContext() {
                 .caching(caching)
                 .languages(languages)
                 .networking(networking)
-                .eventListener(eventListener)
+                .onEvent(onEvent)
+                .onError(onError)
                 .authenticators(authenticators)
                 .build();
     }
diff --git a/sdmx-dl-api/src/main/java/sdmxdl/web/spi/WebCaching.java b/sdmx-dl-api/src/main/java/sdmxdl/web/spi/WebCaching.java
index d0f2c303c..4349ac233 100644
--- a/sdmx-dl-api/src/main/java/sdmxdl/web/spi/WebCaching.java
+++ b/sdmx-dl-api/src/main/java/sdmxdl/web/spi/WebCaching.java
@@ -7,7 +7,9 @@
 import nbbrd.service.ServiceDefinition;
 import nbbrd.service.ServiceId;
 import nbbrd.service.ServiceSorter;
-import sdmxdl.ext.SdmxSourceConsumer;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import sdmxdl.ErrorListener;
+import sdmxdl.EventListener;
 import sdmxdl.web.SdmxWebSource;
 import sdmxdl.web.WebCache;
 
@@ -26,14 +28,17 @@ public interface WebCaching {
     @ServiceSorter(reverse = true)
     int getWebCachingRank();
 
-    @NonNull WebCache getWebCache(@NonNull SdmxWebSource source, @NonNull SdmxSourceConsumer<? super SdmxWebSource, ? super String> listener);
+    @NonNull WebCache getWebCache(
+            @NonNull SdmxWebSource source,
+            @Nullable EventListener<? super SdmxWebSource> onEvent,
+            @Nullable ErrorListener<? super SdmxWebSource> onError);
 
     @NonNull Collection<String> getWebCachingProperties();
 
-    int UNKNOWN_WEB_CACHING_RANK = -1;
-
     @StaticFactoryMethod
     static @NonNull WebCaching noOp() {
         return NoOpCaching.INSTANCE;
     }
+
+    int UNKNOWN_WEB_CACHING_RANK = -1;
 }
diff --git a/sdmx-dl-api/src/main/java/sdmxdl/web/spi/WebContext.java b/sdmx-dl-api/src/main/java/sdmxdl/web/spi/WebContext.java
index bde6e8456..e37ebbb7f 100644
--- a/sdmx-dl-api/src/main/java/sdmxdl/web/spi/WebContext.java
+++ b/sdmx-dl-api/src/main/java/sdmxdl/web/spi/WebContext.java
@@ -17,12 +17,13 @@
 package sdmxdl.web.spi;
 
 import lombok.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import sdmxdl.ErrorListener;
+import sdmxdl.EventListener;
 import sdmxdl.LanguagePriorityList;
-import sdmxdl.SdmxManager;
-import sdmxdl.web.WebCache;
-import sdmxdl.ext.SdmxSourceConsumer;
 import sdmxdl.web.Network;
 import sdmxdl.web.SdmxWebSource;
+import sdmxdl.web.WebCache;
 
 import java.util.List;
 
@@ -41,9 +42,9 @@ public class WebContext {
     @lombok.Builder.Default
     WebCaching caching = WebCaching.noOp();
 
-    @lombok.NonNull
-    @lombok.Builder.Default
-    SdmxSourceConsumer<? super SdmxWebSource, ? super String> eventListener = SdmxManager.NO_OP_EVENT_LISTENER;
+    @Nullable EventListener<? super SdmxWebSource> onEvent;
+
+    @Nullable ErrorListener<? super SdmxWebSource> onError;
 
     @lombok.NonNull
     @lombok.Singular
@@ -54,7 +55,7 @@ public class WebContext {
     Networking networking = Networking.getDefault();
 
     public @NonNull WebCache getCache(@NonNull SdmxWebSource source) {
-        return getCaching().getWebCache(source, getEventListener());
+        return getCaching().getWebCache(source, getOnEvent(), getOnError());
     }
 
     public @NonNull Network getNetwork(@NonNull SdmxWebSource source) {
diff --git a/sdmx-dl-api/src/main/java/sdmxdl/web/spi/WebMonitoring.java b/sdmx-dl-api/src/main/java/sdmxdl/web/spi/WebMonitoring.java
index ee53337e8..726d2200c 100644
--- a/sdmx-dl-api/src/main/java/sdmxdl/web/spi/WebMonitoring.java
+++ b/sdmx-dl-api/src/main/java/sdmxdl/web/spi/WebMonitoring.java
@@ -5,6 +5,7 @@
 import nbbrd.service.Quantifier;
 import nbbrd.service.ServiceDefinition;
 import nbbrd.service.ServiceId;
+import sdmxdl.Marker;
 import sdmxdl.web.MonitorReport;
 import sdmxdl.web.SdmxWebSource;
 
@@ -28,4 +29,6 @@ MonitorReport getReport(
             @NonNull SdmxWebSource source,
             @NonNull WebContext context
     ) throws IOException, IllegalArgumentException;
+
+    Marker WEB_MONITORING_MARKER = Marker.parse("WEB_MONITORING");
 }
diff --git a/sdmx-dl-api/src/test/java/sdmxdl/web/SdmxWebManagerTest.java b/sdmx-dl-api/src/test/java/sdmxdl/web/SdmxWebManagerTest.java
index d80bc9bbb..173baca4b 100644
--- a/sdmx-dl-api/src/test/java/sdmxdl/web/SdmxWebManagerTest.java
+++ b/sdmx-dl-api/src/test/java/sdmxdl/web/SdmxWebManagerTest.java
@@ -17,9 +17,12 @@
 package sdmxdl.web;
 
 import org.junit.jupiter.api.Test;
-import sdmxdl.*;
-import sdmxdl.web.spi.WebCaching;
+import sdmxdl.Connection;
+import sdmxdl.DataRepository;
+import sdmxdl.Feature;
+import sdmxdl.LanguagePriorityList;
 import sdmxdl.web.spi.Networking;
+import sdmxdl.web.spi.WebCaching;
 import sdmxdl.web.spi.WebDriver;
 import tests.sdmxdl.api.SdmxManagerAssert;
 import tests.sdmxdl.web.MockedDriver;
@@ -61,7 +64,7 @@ public void testFactories() {
             assertThat(o.getLanguages()).isEqualTo(LanguagePriorityList.ANY);
             assertThat(o.getNetworking()).isEqualTo(Networking.getDefault());
             assertThat(o.getCaching()).isEqualTo(WebCaching.noOp());
-            assertThat(o.getEventListener()).isEqualTo(SdmxManager.NO_OP_EVENT_LISTENER);
+            assertThat(o.getOnEvent()).isNull();
             assertThat(o.getAuthenticators()).isEmpty();
             assertThat(o.getCustomSources()).isEmpty();
             assertThat(o.getDefaultSources()).isEmpty();
@@ -74,7 +77,7 @@ public void testFactories() {
             assertThat(o.getLanguages()).isEqualTo(LanguagePriorityList.ANY);
             assertThat(o.getNetworking()).isEqualTo(Networking.getDefault());
             assertThat(o.getCaching()).isEqualTo(WebCaching.noOp());
-            assertThat(o.getEventListener()).isEqualTo(SdmxManager.NO_OP_EVENT_LISTENER);
+            assertThat(o.getOnEvent()).isNull();
             assertThat(o.getAuthenticators()).isEmpty();
             assertThat(o.getCustomSources()).isEmpty();
             assertThat(o.getDefaultSources()).isEmpty();
@@ -86,7 +89,7 @@ public void testFactories() {
             assertThat(o.getLanguages()).isEqualTo(LanguagePriorityList.ANY);
             assertThat(o.getNetworking()).isEqualTo(Networking.getDefault());
             assertThat(o.getCaching()).isEqualTo(WebCaching.noOp());
-            assertThat(o.getEventListener()).isEqualTo(SdmxManager.NO_OP_EVENT_LISTENER);
+            assertThat(o.getOnEvent()).isNull();
             assertThat(o.getAuthenticators()).isEmpty();
             assertThat(o.getCustomSources()).isEmpty();
             assertThat(o.getDefaultSources()).containsAll(sampleDriver.getDefaultSources());
@@ -247,7 +250,7 @@ public void testInvalidSourceProperties() throws IOException {
         SdmxWebManager manager = SdmxWebManager
                 .builder()
                 .driver(sampleDriver)
-                .eventListener((source, event) -> events.add(source.getId() + ":" + event))
+                .onEvent((source, marker, event) -> events.add(source.getId() + ":" + event))
                 .build();
 
         SdmxWebSource noProp = sampleSource.toBuilder().id("noProp").clearProperties().build();
diff --git a/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/WebNetOptions.java b/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/WebNetOptions.java
index 52df4064c..925f8671d 100644
--- a/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/WebNetOptions.java
+++ b/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/WebNetOptions.java
@@ -16,6 +16,7 @@
  */
 package internal.sdmxdl.cli;
 
+import internal.sdmxdl.cli.ext.Anchor;
 import internal.sdmxdl.cli.ext.AuthOptions;
 import internal.sdmxdl.cli.ext.CacheOptions;
 import internal.sdmxdl.cli.ext.VerboseOptions;
@@ -23,8 +24,6 @@
 import lombok.NonNull;
 import nl.altindag.ssl.SSLFactory;
 import picocli.CommandLine;
-import sdmxdl.web.spi.WebCaching;
-import sdmxdl.file.SdmxFileSource;
 import sdmxdl.format.DiskCache;
 import sdmxdl.format.DiskCachingSupport;
 import sdmxdl.format.MemCachingSupport;
@@ -34,6 +33,7 @@
 import sdmxdl.web.SdmxWebSource;
 import sdmxdl.web.spi.Networking;
 import sdmxdl.web.spi.WebAuthenticator;
+import sdmxdl.web.spi.WebCaching;
 
 import javax.net.ssl.HostnameVerifier;
 import javax.net.ssl.SSLSocketFactory;
@@ -136,8 +136,6 @@ private static WebCaching getCacheProvider(CacheOptions cacheOptions, VerboseOpt
                         .id("DISK")
                         .root(root)
                         .persistence(cacheOptions.getCacheFormat())
-                        .onFileError((src, msg, ex) -> reportFileError(verboseOptions, src, msg, ex))
-                        .onWebError((src, msg, ex) -> reportWebError(verboseOptions, src, msg, ex))
                         .clock(clock)
                         .noCompression(cacheOptions.isNoCacheCompression())
                         .build())
@@ -147,17 +145,7 @@ private static WebCaching getCacheProvider(CacheOptions cacheOptions, VerboseOpt
 
     private static void reportConfig(VerboseOptions verboseOptions, Path root) {
         if (verboseOptions.isVerbose())
-            verboseOptions.reportToErrorStream(CACHE_ANCHOR, "Using cache folder '" + root + "'");
-    }
-
-    private static void reportFileError(VerboseOptions verboseOptions, SdmxFileSource src, String msg, IOException ex) {
-        if (verboseOptions.isVerbose())
-            verboseOptions.reportToErrorStream(CACHE_ANCHOR, src.getData() + ": " + msg, ex);
-    }
-
-    private static void reportWebError(VerboseOptions verboseOptions, SdmxWebSource src, String msg, IOException ex) {
-        if (verboseOptions.isVerbose())
-            verboseOptions.reportToErrorStream(CACHE_ANCHOR, src.getId() + ": " + msg, ex);
+            verboseOptions.reportToErrorStream(Anchor.CCH, "Using cache folder '" + root + "'");
     }
 
     private static Networking getNetworking(NetworkOptions networkOptions, VerboseOptions verboseOptions) {
@@ -172,7 +160,7 @@ private static Networking getNetworking(NetworkOptions networkOptions, VerboseOp
 
     private static void reportNetwork(VerboseOptions verboseOptions, String msg) {
         if (verboseOptions.isVerbose())
-            verboseOptions.reportToErrorStream("NET", msg);
+            verboseOptions.reportToErrorStream(Anchor.NET, msg);
     }
 
     private static <T> Supplier<T> memoize(Supplier<T> supplier, String message, VerboseOptions verboseOptions) {
diff --git a/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/WebOptions.java b/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/WebOptions.java
index f561a803b..9a57e3fb3 100644
--- a/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/WebOptions.java
+++ b/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/WebOptions.java
@@ -16,15 +16,18 @@
  */
 package internal.sdmxdl.cli;
 
+import internal.sdmxdl.cli.ext.Anchor;
 import internal.sdmxdl.cli.ext.CloseableExecutorService;
 import internal.sdmxdl.cli.ext.SameThreadExecutorService;
 import internal.sdmxdl.cli.ext.VerboseOptions;
 import nbbrd.design.ReturnNew;
 import nbbrd.io.text.BooleanProperty;
+import org.checkerframework.checker.nullness.qual.Nullable;
 import picocli.CommandLine;
+import sdmxdl.ErrorListener;
+import sdmxdl.EventListener;
 import sdmxdl.LanguagePriorityList;
-import sdmxdl.SdmxManager;
-import sdmxdl.ext.SdmxSourceConsumer;
+import sdmxdl.Marker;
 import sdmxdl.format.xml.XmlWebSource;
 import sdmxdl.web.SdmxWebManager;
 import sdmxdl.web.SdmxWebSource;
@@ -37,7 +40,6 @@
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
-import java.util.function.BiConsumer;
 import java.util.logging.Level;
 
 /**
@@ -104,7 +106,8 @@ public SdmxWebManager loadManager() throws IOException {
             return defaultWebManager.get()
                     .toBuilder()
                     .languages(langs)
-                    .eventListener(getEventListener())
+                    .onEvent(getEventListener())
+                    .onError(getErrorListener())
                     .customSources(customSources.get())
                     .build();
 
@@ -113,9 +116,14 @@ public SdmxWebManager loadManager() throws IOException {
         }
     }
 
-    private SdmxSourceConsumer<? super SdmxWebSource, ? super String> getEventListener() {
-        SdmxSourceConsumer<? super SdmxWebSource, ? super String> original = isNoLog() ? SdmxManager.NO_OP_EVENT_LISTENER : new LoggingListener()::onSourceEvent;
-        return new VerboseListener(original, verboseOptions)::onSourceEvent;
+    private EventListener<? super SdmxWebSource> getEventListener() {
+        EventListener<? super SdmxWebSource> original = isNoLog() ? null : new LoggingListener()::onSourceEvent;
+        return new VerboseEventListener(original, verboseOptions)::onSourceEvent;
+    }
+
+    private ErrorListener<? super SdmxWebSource> getErrorListener() {
+        ErrorListener<? super SdmxWebSource> original = isNoLog() ? null : new LoggingListener()::onSourceError;
+        return new VerboseErrorListener(original, verboseOptions)::onSourceError;
     }
 
     @ReturnNew
@@ -127,7 +135,7 @@ private SdmxWebManager loadDefaultWebManager() {
     private List<SdmxWebSource> loadCustomSources() throws IOException {
         if (sourcesFile != null) {
             if (verboseOptions.isVerbose()) {
-                verboseOptions.reportToErrorStream("CFG", "Using source file '" + sourcesFile + "'");
+                verboseOptions.reportToErrorStream(Anchor.CFG, "Using source file '" + sourcesFile + "'");
             }
             return XmlWebSource.getParser().parseFile(sourcesFile);
         }
@@ -137,28 +145,51 @@ private List<SdmxWebSource> loadCustomSources() throws IOException {
     @lombok.extern.java.Log
     private static class LoggingListener {
 
-        public void onSourceEvent(SdmxWebSource source, String message) {
+        public void onSourceEvent(SdmxWebSource source, Marker marker, CharSequence message) {
             if (log.isLoggable(Level.INFO)) {
-                log.info(message);
+                log.info(message.toString());
+            }
+        }
+
+        public void onSourceError(SdmxWebSource source, Marker marker, CharSequence message, IOException error) {
+            if (log.isLoggable(Level.INFO)) {
+                log.log(Level.INFO, message.toString(), error);
             }
         }
     }
 
     @lombok.AllArgsConstructor
-    private static class VerboseListener {
+    private static class VerboseEventListener {
+
+        private final @Nullable EventListener<? super SdmxWebSource> main;
 
         @lombok.NonNull
-        private final BiConsumer<? super SdmxWebSource, ? super String> main;
+        private final VerboseOptions verboseOptions;
+
+        public void onSourceEvent(SdmxWebSource source, Marker marker, CharSequence message) {
+            if (main != null) {
+                main.accept(source, marker, message);
+            }
+            if (verboseOptions.isVerbose()) {
+                verboseOptions.reportToErrorStream(Anchor.WEB, source.getId() + ": " + message);
+            }
+        }
+    }
+
+    @lombok.AllArgsConstructor
+    private static class VerboseErrorListener {
+
+        private final @Nullable ErrorListener<? super SdmxWebSource> main;
 
         @lombok.NonNull
         private final VerboseOptions verboseOptions;
 
-        public void onSourceEvent(SdmxWebSource source, String message) {
-            if (main != SdmxManager.NO_OP_EVENT_LISTENER) {
-                main.accept(source, message);
+        public void onSourceError(SdmxWebSource source, Marker marker, CharSequence message, IOException error) {
+            if (main != null) {
+                main.accept(source, marker, message, error);
             }
             if (verboseOptions.isVerbose()) {
-                verboseOptions.reportToErrorStream("WEB", source.getId() + ": " + message);
+                verboseOptions.reportToErrorStream(Anchor.WEB, source.getId() + ": " + message, error);
             }
         }
     }
diff --git a/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/ext/Anchor.java b/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/ext/Anchor.java
new file mode 100644
index 000000000..cef4f2b0f
--- /dev/null
+++ b/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/ext/Anchor.java
@@ -0,0 +1,5 @@
+package internal.sdmxdl.cli.ext;
+
+public enum Anchor {
+    CFG, CCH, NET, WEB
+}
diff --git a/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/ext/VerboseOptions.java b/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/ext/VerboseOptions.java
index a482216ca..34c792a91 100644
--- a/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/ext/VerboseOptions.java
+++ b/sdmx-dl-cli/src/main/java/internal/sdmxdl/cli/ext/VerboseOptions.java
@@ -18,24 +18,24 @@ public class VerboseOptions {
     @CommandLine.Spec
     private CommandLine.Model.CommandSpec spec;
 
-    public void reportToErrorStream(String anchor, String message) {
+    public void reportToErrorStream(Anchor anchor, String message) {
         if (verbose) {
             CommandLine.Help.ColorScheme colorScheme = spec.commandLine().getColorScheme();
             reportToErrorStream(colorScheme
                     .text("[")
-                    .concat(colorScheme.commandText(anchor))
+                    .concat(colorScheme.commandText(anchor.toString()))
                     .concat(colorScheme.text("] "))
                     .concat(colorScheme.optionText(message))
             );
         }
     }
 
-    public void reportToErrorStream(String anchor, String message, Exception ex) {
+    public void reportToErrorStream(Anchor anchor, String message, Exception ex) {
         CommandLine.Help.ColorScheme colorScheme = spec.commandLine().getColorScheme();
         String details = ex.getMessage() != null ? ex.getMessage() : ex.getClass().getName();
         reportToErrorStream(colorScheme
                 .text("[")
-                .concat(colorScheme.commandText(anchor))
+                .concat(colorScheme.commandText(anchor.toString()))
                 .concat(colorScheme.text("] "))
                 .concat(colorScheme.optionText(message))
                 .concat(" ")
diff --git a/sdmx-dl-cli/src/main/java/sdmxdl/cli/CheckConfigCommand.java b/sdmx-dl-cli/src/main/java/sdmxdl/cli/CheckConfigCommand.java
index 227cf4bd7..3ebbb892e 100644
--- a/sdmx-dl-cli/src/main/java/sdmxdl/cli/CheckConfigCommand.java
+++ b/sdmx-dl-cli/src/main/java/sdmxdl/cli/CheckConfigCommand.java
@@ -16,6 +16,7 @@
  */
 package sdmxdl.cli;
 
+import internal.sdmxdl.cli.ext.Anchor;
 import internal.sdmxdl.cli.ext.CsvTable;
 import internal.sdmxdl.cli.ext.RFC4180OutputOptions;
 import internal.sdmxdl.cli.ext.VerboseOptions;
@@ -73,7 +74,7 @@ private ConfigHelper getConfigHelper() {
         return ConfigHelper
                 .builder()
                 .appName(About.NAME)
-                .onLoadingError((path, ex) -> verboseOptions.reportToErrorStream("CFG", path.toString(), ex))
+                .onLoadingError((path, ex) -> verboseOptions.reportToErrorStream(Anchor.CFG, path.toString(), ex))
                 .build();
     }
 
diff --git a/sdmx-dl-cli/src/test/java/_demo/Demo.java b/sdmx-dl-cli/src/test/java/_demo/Demo.java
index 29e8ff5be..42321e3a9 100644
--- a/sdmx-dl-cli/src/test/java/_demo/Demo.java
+++ b/sdmx-dl-cli/src/test/java/_demo/Demo.java
@@ -4,6 +4,7 @@
 import sdmxdl.*;
 import sdmxdl.provider.web.SingleNetworkingSupport;
 import sdmxdl.web.SdmxWebManager;
+import sdmxdl.web.SdmxWebSource;
 
 import java.io.IOException;
 
@@ -16,7 +17,7 @@ public static void main(String[] args) throws IOException {
                 .toBuilder()
                 .networking(SingleNetworkingSupport.builder().id("CURL").urlConnectionFactoryOf(CurlHttpURLConnection::of).build())
                 .languages(LanguagePriorityList.ANY)
-                .eventListener((source, message) -> System.err.println("[" + source.getId() + "] " + message))
+                .onEvent(Demo::printEvent)
                 .build();
 
         try (Connection ecb = manager.getConnection("ECB")) {
@@ -31,4 +32,8 @@ public static void main(String[] args) throws IOException {
                     .forEach(System.out::println);
         }
     }
+
+    private static void printEvent(SdmxWebSource source, Marker marker, CharSequence message) {
+        System.err.println("[" + source.getId() + "] (" + marker + ") " + message);
+    }
 }
diff --git a/sdmx-dl-desktop/src/main/java/internal/sdmxdl/desktop/DesktopWebFactory.java b/sdmx-dl-desktop/src/main/java/internal/sdmxdl/desktop/DesktopWebFactory.java
index 5e03e48b8..fe524ad71 100644
--- a/sdmx-dl-desktop/src/main/java/internal/sdmxdl/desktop/DesktopWebFactory.java
+++ b/sdmx-dl-desktop/src/main/java/internal/sdmxdl/desktop/DesktopWebFactory.java
@@ -14,7 +14,7 @@ public static SdmxWebManager loadManager() {
         return SdmxWebManager.ofServiceLoader()
                 .toBuilder()
                 .networking(SingleNetworkingSupport.builder().id("CURL").urlConnectionFactoryOf(CurlHttpURLConnection::of).build())
-                .eventListener((source, msg) -> System.out.println(source.getId() + ": " + msg))
+                .onEvent((source, marker, msg) -> System.out.println(source.getId() + ": " + msg))
                 .build();
     }
 }
diff --git a/sdmx-dl-format-base/src/main/java/sdmxdl/format/DiskCache.java b/sdmx-dl-format-base/src/main/java/sdmxdl/format/DiskCache.java
index 18784047a..b27fb8a4a 100644
--- a/sdmx-dl-format-base/src/main/java/sdmxdl/format/DiskCache.java
+++ b/sdmx-dl-format-base/src/main/java/sdmxdl/format/DiskCache.java
@@ -34,6 +34,7 @@
 import java.time.Clock;
 import java.util.Locale;
 import java.util.function.BiConsumer;
+import java.util.function.Consumer;
 import java.util.function.Predicate;
 import java.util.function.UnaryOperator;
 
@@ -70,13 +71,9 @@ public final class DiskCache implements FileCache, WebCache {
     @lombok.Builder.Default
     private final FileFormat<MonitorReports> monitorFormat = FileFormat.noOp();
 
-    @lombok.NonNull
-    @lombok.Builder.Default
-    private final BiConsumer<? super String, ? super DiskCacheEvent> onRead = DO_NOT_REPORT;
+    private final @Nullable Consumer<? super String> onRead;
 
-    @lombok.NonNull
-    @lombok.Builder.Default
-    private final BiConsumer<? super String, ? super IOException> onError = DO_NOT_REPORT;
+    private final @Nullable BiConsumer<? super String, ? super IOException> onError;
 
     @lombok.NonNull
     @lombok.Builder.Default
@@ -133,25 +130,29 @@ private boolean isValid(MonitorReports value) {
     private <T> T read(FileFormat<T> fileFormat, Predicate<T> validator, String key, FileType fileType) {
         T result = read(fileFormat, fileType, key);
         if (result == null) {
-            onRead.accept(key, DiskCacheEvent.MISSED);
+            reportRead(key, DiskCacheEvent.MISSED);
             return null;
         }
         if (!validator.test(result)) {
             delete(key, fileType, fileFormat);
-            onRead.accept(key, DiskCacheEvent.EXPIRED);
+            reportRead(key, DiskCacheEvent.EXPIRED);
             return null;
         }
-        onRead.accept(key, DiskCacheEvent.HIT);
+        reportRead(key, DiskCacheEvent.HIT);
         return result;
     }
 
+    private void reportRead(String key, DiskCacheEvent event) {
+        if (onRead != null) onRead.accept(event.name() + " " + key);
+    }
+
     private <T> T read(FileFormat<T> fileFormat, FileType fileType, String key) {
         Path file = getFile(key, fileType, fileFormat);
         if (Files.exists(file) && Files.isRegularFile(file)) {
             try {
                 return FileParser.onParsingLock(fileFormat.getParser()).parsePath(file);
             } catch (IOException ex) {
-                onError.accept("Failed reading '" + file + "'", ex);
+                if (onError != null) onError.accept("Failed reading '" + file + "'", ex);
             }
         }
         return null;
@@ -163,7 +164,7 @@ private <T> void write(FileFormat<T> fileFormat, String key, FileType fileType,
         try {
             FileFormatter.onFormattingLock(fileFormat.getFormatter()).formatPath(entry, file);
         } catch (IOException ex) {
-            onError.accept("Failed writing '" + file + "'", ex);
+            if (onError != null) onError.accept("Failed writing '" + file + "'", ex);
         }
     }
 
@@ -171,7 +172,7 @@ private void ensureParentExists(Path file) {
         try {
             Files.createDirectories(file.getParent());
         } catch (IOException ex) {
-            onError.accept("While creating working dir '" + file + "'", ex);
+            if (onError != null) onError.accept("While creating working dir '" + file + "'", ex);
         }
     }
 
@@ -180,7 +181,7 @@ private void delete(String key, FileType fileType, FileFormat<?> fileFormat) {
         try {
             Files.deleteIfExists(file);
         } catch (IOException ex) {
-            onError.accept("While deleting '" + file + "'", ex);
+            if (onError != null) onError.accept("While deleting '" + file + "'", ex);
         }
     }
 
@@ -191,8 +192,6 @@ Path getFile(String key, FileType fileType, FileFormat<?> fileFormat) {
 
     public static final Path SDMXDL_TMP_DIR = requireNonNull(SystemProperties.DEFAULT.getJavaIoTmpdir()).resolve(About.NAME).resolve(About.VERSION);
     private static final UnaryOperator<String> NORMALIZE_HASH_CODE = DiskCache::normalizeHashCode;
-    private static final BiConsumer<Object, Object> DO_NOT_REPORT = (msg, ex) -> {
-    };
 
     private static String normalizeHashCode(String key) {
         int hashCode = key.hashCode();
@@ -203,4 +202,9 @@ private static String normalizeHashCode(String key) {
     enum FileType {
         REPOSITORY, MONITOR
     }
+
+    @VisibleForTesting
+    enum DiskCacheEvent {
+        HIT, MISSED, EXPIRED
+    }
 }
diff --git a/sdmx-dl-format-base/src/main/java/sdmxdl/format/DiskCacheEvent.java b/sdmx-dl-format-base/src/main/java/sdmxdl/format/DiskCacheEvent.java
deleted file mode 100644
index ecf8656ff..000000000
--- a/sdmx-dl-format-base/src/main/java/sdmxdl/format/DiskCacheEvent.java
+++ /dev/null
@@ -1,6 +0,0 @@
-package sdmxdl.format;
-
-public enum DiskCacheEvent {
-
-    HIT, MISSED, EXPIRED
-}
diff --git a/sdmx-dl-format-base/src/main/java/sdmxdl/format/DiskCachingSupport.java b/sdmx-dl-format-base/src/main/java/sdmxdl/format/DiskCachingSupport.java
index f128acb70..ebb6bde91 100644
--- a/sdmx-dl-format-base/src/main/java/sdmxdl/format/DiskCachingSupport.java
+++ b/sdmx-dl-format-base/src/main/java/sdmxdl/format/DiskCachingSupport.java
@@ -1,9 +1,11 @@
 package sdmxdl.format;
 
 import lombok.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 import sdmxdl.DataRepository;
-import sdmxdl.ext.SdmxSourceBiConsumer;
-import sdmxdl.ext.SdmxSourceConsumer;
+import sdmxdl.ErrorListener;
+import sdmxdl.EventListener;
+import sdmxdl.Marker;
 import sdmxdl.file.FileCache;
 import sdmxdl.file.SdmxFileSource;
 import sdmxdl.file.spi.FileCaching;
@@ -13,7 +15,6 @@
 import sdmxdl.web.WebCache;
 import sdmxdl.web.spi.WebCaching;
 
-import java.io.IOException;
 import java.nio.file.Path;
 import java.time.Clock;
 import java.util.Collection;
@@ -40,14 +41,6 @@ public final class DiskCachingSupport implements FileCaching, WebCaching {
     @lombok.Builder.Default
     private final FileFormat<MonitorReports> monitorFormat = FileFormat.noOp();
 
-    @lombok.NonNull
-    @lombok.Builder.Default
-    private final SdmxSourceBiConsumer<SdmxFileSource, ? super String, ? super IOException> onFileError = NO_OP_FILE_ERROR;
-
-    @lombok.NonNull
-    @lombok.Builder.Default
-    private final SdmxSourceBiConsumer<SdmxWebSource, ? super String, ? super IOException> onWebError = NO_OP_WEB_ERROR;
-
     @lombok.NonNull
     @lombok.Builder.Default
     private final Clock clock = Clock.systemDefaultZone();
@@ -85,18 +78,18 @@ public int getWebCachingRank() {
     }
 
     @Override
-    public @NonNull FileCache getFileCache(@NonNull SdmxFileSource source, @NonNull SdmxSourceConsumer<? super SdmxFileSource, ? super String> listener) {
+    public @NonNull FileCache getFileCache(@NonNull SdmxFileSource source, @Nullable EventListener<? super SdmxFileSource> onEvent, @Nullable ErrorListener<? super SdmxFileSource> onError) {
         return newFileCacheBuilder()
-                .onRead((key, event) -> listener.accept(source, event.name() + " " + key))
-                .onError(onFileError.asBiConsumer(source))
+                .onRead(onEvent != null ? onEvent.asConsumer(source, Marker.parse(id)) : null)
+                .onError(onError != null ? onError.asBiConsumer(source, Marker.parse(id)) : null)
                 .build();
     }
 
     @Override
-    public @NonNull WebCache getWebCache(@NonNull SdmxWebSource source, @NonNull SdmxSourceConsumer<? super SdmxWebSource, ? super String> listener) {
+    public @NonNull WebCache getWebCache(@NonNull SdmxWebSource source, @Nullable EventListener<? super SdmxWebSource> onEvent, @Nullable ErrorListener<? super SdmxWebSource> onError) {
         return newFileCacheBuilder()
-                .onRead((key, event) -> listener.accept(source, event.name() + " " + key))
-                .onError(onWebError.asBiConsumer(source))
+                .onRead(onEvent != null ? onEvent.asConsumer(source, Marker.parse(id)) : null)
+                .onError(onError != null ? onError.asBiConsumer(source, Marker.parse(id)) : null)
                 .build();
     }
 
@@ -118,10 +111,4 @@ public static final class Builder {
             return this;
         }
     }
-
-    public static final SdmxSourceBiConsumer<SdmxFileSource, ? super String, ? super IOException> NO_OP_FILE_ERROR = (source, t, u) -> {
-    };
-
-    public static final SdmxSourceBiConsumer<SdmxWebSource, ? super String, ? super IOException> NO_OP_WEB_ERROR = (source, t, u) -> {
-    };
 }
diff --git a/sdmx-dl-format-base/src/main/java/sdmxdl/format/MemCachingSupport.java b/sdmx-dl-format-base/src/main/java/sdmxdl/format/MemCachingSupport.java
index e6f6c032a..422bc419b 100644
--- a/sdmx-dl-format-base/src/main/java/sdmxdl/format/MemCachingSupport.java
+++ b/sdmx-dl-format-base/src/main/java/sdmxdl/format/MemCachingSupport.java
@@ -1,8 +1,10 @@
 package sdmxdl.format;
 
 import lombok.NonNull;
+import org.checkerframework.checker.nullness.qual.Nullable;
 import sdmxdl.DataRepository;
-import sdmxdl.ext.SdmxSourceConsumer;
+import sdmxdl.ErrorListener;
+import sdmxdl.EventListener;
 import sdmxdl.file.FileCache;
 import sdmxdl.file.SdmxFileSource;
 import sdmxdl.file.spi.FileCaching;
@@ -61,12 +63,12 @@ public int getWebCachingRank() {
     }
 
     @Override
-    public @NonNull FileCache getFileCache(@NonNull SdmxFileSource source, @NonNull SdmxSourceConsumer<? super SdmxFileSource, ? super String> eventListener) {
+    public @NonNull FileCache getFileCache(@NonNull SdmxFileSource source, @Nullable EventListener<? super SdmxFileSource> onEvent, @Nullable ErrorListener<? super SdmxFileSource> onError) {
         return getCache();
     }
 
     @Override
-    public @NonNull WebCache getWebCache(@NonNull SdmxWebSource source, @NonNull SdmxSourceConsumer<? super SdmxWebSource, ? super String> listener) {
+    public @NonNull WebCache getWebCache(@NonNull SdmxWebSource source, @Nullable EventListener<? super SdmxWebSource> onEvent, @Nullable ErrorListener<? super SdmxWebSource> onError) {
         return getCache();
     }
 
diff --git a/sdmx-dl-format-base/src/test/java/sdmxdl/format/MemCachingSupportTest.java b/sdmx-dl-format-base/src/test/java/sdmxdl/format/MemCachingSupportTest.java
index cafea0e44..4612eff70 100644
--- a/sdmx-dl-format-base/src/test/java/sdmxdl/format/MemCachingSupportTest.java
+++ b/sdmx-dl-format-base/src/test/java/sdmxdl/format/MemCachingSupportTest.java
@@ -3,7 +3,6 @@
 import nbbrd.io.text.Parser;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.EnumSource;
-import sdmxdl.SdmxManager;
 import sdmxdl.file.SdmxFileSource;
 import sdmxdl.web.SdmxWebSource;
 
@@ -38,12 +37,12 @@ enum Extractor {
         FILE {
             @Override
             MemCache f(MemCachingSupport z) {
-                return (MemCache) z.getFileCache(FILE_SOURCE, SdmxManager.NO_OP_EVENT_LISTENER);
+                return (MemCache) z.getFileCache(FILE_SOURCE, null, null);
             }
         }, WEB {
             @Override
             MemCache f(MemCachingSupport z) {
-                return (MemCache) z.getWebCache(WEB_SOURCE, SdmxManager.NO_OP_EVENT_LISTENER);
+                return (MemCache) z.getWebCache(WEB_SOURCE, null, null);
             }
         };
 
diff --git a/sdmx-dl-provider-base/src/main/java/sdmxdl/provider/ext/DualWebCachingSupport.java b/sdmx-dl-provider-base/src/main/java/sdmxdl/provider/ext/DualWebCachingSupport.java
index a93ce8f1a..4b5bef46b 100644
--- a/sdmx-dl-provider-base/src/main/java/sdmxdl/provider/ext/DualWebCachingSupport.java
+++ b/sdmx-dl-provider-base/src/main/java/sdmxdl/provider/ext/DualWebCachingSupport.java
@@ -1,7 +1,9 @@
 package sdmxdl.provider.ext;
 
 import lombok.NonNull;
-import sdmxdl.ext.SdmxSourceConsumer;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import sdmxdl.ErrorListener;
+import sdmxdl.EventListener;
 import sdmxdl.web.SdmxWebSource;
 import sdmxdl.web.WebCache;
 import sdmxdl.web.spi.WebCaching;
@@ -44,9 +46,9 @@ public int getWebCachingRank() {
     }
 
     @Override
-    public @NonNull WebCache getWebCache(@NonNull SdmxWebSource source, @NonNull SdmxSourceConsumer<? super SdmxWebSource, ? super String> listener) {
-        WebCache main = first.getWebCache(source, listener);
-        return new DualWebCache(main, second.getWebCache(source, listener), clock);
+    public @NonNull WebCache getWebCache(@NonNull SdmxWebSource source, @Nullable EventListener<? super SdmxWebSource> onEvent, @Nullable ErrorListener<? super SdmxWebSource> onError) {
+        WebCache main = first.getWebCache(source, onEvent, onError);
+        return new DualWebCache(main, second.getWebCache(source, onEvent, onError), clock);
     }
 
     @Override
diff --git a/sdmx-dl-provider-base/src/main/java/sdmxdl/provider/file/FileClient.java b/sdmx-dl-provider-base/src/main/java/sdmxdl/provider/file/FileClient.java
index 9b06f9f82..8ee97b87c 100644
--- a/sdmx-dl-provider-base/src/main/java/sdmxdl/provider/file/FileClient.java
+++ b/sdmx-dl-provider-base/src/main/java/sdmxdl/provider/file/FileClient.java
@@ -1,6 +1,7 @@
 package sdmxdl.provider.file;
 
 import lombok.NonNull;
+import sdmxdl.Marker;
 import sdmxdl.Series;
 import sdmxdl.provider.DataRef;
 import sdmxdl.provider.HasMarker;
@@ -15,4 +16,6 @@ public interface FileClient extends HasMarker {
     @NonNull FileInfo decode() throws IOException;
 
     @NonNull Stream<Series> loadData(@NonNull FileInfo info, @NonNull DataRef dataRef) throws IOException;
+
+    Marker FILE_CLIENT_MARKER = Marker.parse("FILE_CLIENT");
 }
diff --git a/sdmx-dl-provider-base/src/main/java/sdmxdl/provider/web/RestClient.java b/sdmx-dl-provider-base/src/main/java/sdmxdl/provider/web/RestClient.java
index 301e279cd..442c7f89c 100644
--- a/sdmx-dl-provider-base/src/main/java/sdmxdl/provider/web/RestClient.java
+++ b/sdmx-dl-provider-base/src/main/java/sdmxdl/provider/web/RestClient.java
@@ -44,4 +44,6 @@ public interface RestClient extends HasMarker {
     @NonNull Set<Feature> getSupportedFeatures() throws IOException;
 
     void testClient() throws IOException;
+
+    Marker REST_CLIENT_MARKER = sdmxdl.Marker.parse("REST_CLIENT");
 }
diff --git a/sdmx-dl-provider-connectors/src/main/java/internal/sdmxdl/provider/connectors/ConnectorsRestClient.java b/sdmx-dl-provider-connectors/src/main/java/internal/sdmxdl/provider/connectors/ConnectorsRestClient.java
index 6fc210a02..080ca5761 100644
--- a/sdmx-dl-provider-connectors/src/main/java/internal/sdmxdl/provider/connectors/ConnectorsRestClient.java
+++ b/sdmx-dl-provider-connectors/src/main/java/internal/sdmxdl/provider/connectors/ConnectorsRestClient.java
@@ -26,6 +26,8 @@
 import lombok.AccessLevel;
 import lombok.NonNull;
 import nbbrd.io.text.BaseProperty;
+import org.checkerframework.checker.nullness.qual.Nullable;
+import sdmxdl.EventListener;
 import sdmxdl.*;
 import sdmxdl.format.ObsParser;
 import sdmxdl.provider.DataRef;
@@ -42,7 +44,6 @@
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.*;
-import java.util.function.BiConsumer;
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -171,7 +172,7 @@ public interface GenericSupplier {
     }
 
     @Override
-    public Set<Feature> getSupportedFeatures() {
+    public @NonNull Set<Feature> getSupportedFeatures() {
         return connector instanceof HasDetailSupported
                 && ((HasDetailSupported) connector).isDetailSupported()
                 ? EnumSet.of(Feature.DATA_QUERY_ALL_KEYWORD, Feature.DATA_QUERY_DETAIL)
@@ -216,7 +217,7 @@ private static void configure(RestSdmxClient client, SdmxWebSource source, WebCo
         client.setSslSocketFactory(sslFactory.getSSLSocketFactory());
         client.setHostnameVerifier(sslFactory.getHostnameVerifier());
         client.setMaxRedirects(MAX_REDIRECTS_PROPERTY.get(source.getProperties()));
-        RestSdmxEventListener eventListener = new DefaultRestSdmxEventListener(source, context.getEventListener());
+        RestSdmxEventListener eventListener = new DefaultRestSdmxEventListener(source, context.getOnEvent());
         client.setRedirectionEventListener(eventListener);
         client.setOpenEventListener(eventListener);
     }
@@ -227,18 +228,17 @@ private static final class DefaultRestSdmxEventListener implements RestSdmxEvent
         @lombok.NonNull
         private final SdmxWebSource source;
 
-        @lombok.NonNull
-        private final BiConsumer<? super SdmxWebSource, ? super String> listener;
+        private final @Nullable EventListener<? super SdmxWebSource> listener;
 
         @Override
         public void onSdmxEvent(RestSdmxEvent event) {
-            if (listener != SdmxManager.NO_OP_EVENT_LISTENER) {
+            if (listener != null) {
                 if (event instanceof RedirectionEvent) {
                     RedirectionEvent redirectionEvent = (RedirectionEvent) event;
-                    listener.accept(source, WebEvents.onRedirection(redirectionEvent.getUrl(), redirectionEvent.getRedirection()));
+                    listener.accept(source, REST_CLIENT_MARKER, WebEvents.onRedirection(redirectionEvent.getUrl(), redirectionEvent.getRedirection()));
                 } else if (event instanceof OpenEvent) {
                     OpenEvent openEvent = (OpenEvent) event;
-                    listener.accept(source, WebEvents.onQuery(openEvent.getUrl(), openEvent.getProxy()));
+                    listener.accept(source, REST_CLIENT_MARKER, WebEvents.onQuery(openEvent.getUrl(), openEvent.getProxy()));
                 }
             }
         }
diff --git a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/SdmxDecoder.java b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/SdmxDecoder.java
index 57a7c4b30..3a1637f9c 100644
--- a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/SdmxDecoder.java
+++ b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/SdmxDecoder.java
@@ -18,6 +18,7 @@
 
 import lombok.NonNull;
 import sdmxdl.LanguagePriorityList;
+import sdmxdl.Marker;
 import sdmxdl.file.SdmxFileSource;
 import sdmxdl.provider.file.FileInfo;
 
@@ -29,4 +30,6 @@
 public interface SdmxDecoder {
 
     @NonNull FileInfo decode(@NonNull SdmxFileSource source, @NonNull LanguagePriorityList languages) throws IOException;
+
+    Marker SDMX_DECODER_MARKER = Marker.parse("SDMX_DECODER");
 }
diff --git a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/XmlDecoder.java b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/XmlDecoder.java
index 598e60fbd..f13ceff1f 100644
--- a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/XmlDecoder.java
+++ b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/XmlDecoder.java
@@ -16,18 +16,19 @@
  */
 package internal.sdmxdl.provider.ri.file;
 
+import lombok.NonNull;
 import nbbrd.io.net.MediaType;
 import nbbrd.io.xml.Xml;
+import org.checkerframework.checker.nullness.qual.Nullable;
 import sdmxdl.DataStructure;
+import sdmxdl.EventListener;
 import sdmxdl.LanguagePriorityList;
-import sdmxdl.SdmxManager;
 import sdmxdl.file.SdmxFileSource;
 import sdmxdl.format.xml.*;
 import sdmxdl.provider.file.FileInfo;
 
 import java.io.IOException;
 import java.util.List;
-import java.util.function.BiConsumer;
 
 /**
  * @author Philippe Charles
@@ -35,18 +36,17 @@
 @lombok.AllArgsConstructor
 public final class XmlDecoder implements SdmxDecoder {
 
-    @lombok.NonNull
-    private final BiConsumer<? super SdmxFileSource, ? super String> eventListener;
+    private final @Nullable EventListener<? super SdmxFileSource> listener;
 
     @Override
-    public FileInfo decode(SdmxFileSource source, LanguagePriorityList langs) throws IOException {
+    public @NonNull FileInfo decode(@NonNull SdmxFileSource source, @NonNull LanguagePriorityList langs) throws IOException {
         MediaType type = probeDataType(source);
         return FileInfo.of(type, loadStructure(source, langs, type));
     }
 
     private MediaType probeDataType(SdmxFileSource source) throws IOException {
-        if (eventListener != SdmxManager.NO_OP_EVENT_LISTENER) {
-            eventListener.accept(source, "Probing data type from '" + source.getData() + "'");
+        if (listener != null) {
+            listener.accept(source, SDMX_DECODER_MARKER, "Probing data type from '" + source.getData() + "'");
         }
         return XmlMediaTypeProbe.of()
                 .parseFile(source.getData())
@@ -60,8 +60,8 @@ private DataStructure loadStructure(SdmxFileSource source, LanguagePriorityList
     }
 
     private DataStructure parseStruct(MediaType dataType, LanguagePriorityList langs, SdmxFileSource source) throws IOException {
-        if (eventListener != SdmxManager.NO_OP_EVENT_LISTENER) {
-            eventListener.accept(source, "Parsing structure from '" + source.getStructure() + "' with data type '" + dataType + "'");
+        if (listener != null) {
+            listener.accept(source, SDMX_DECODER_MARKER, "Parsing structure from '" + source.getStructure() + "' with data type '" + dataType + "'");
         }
         return getStructParser(dataType, langs)
                 .parseFile(source.getStructure())
@@ -80,8 +80,8 @@ private Xml.Parser<List<DataStructure>> getStructParser(MediaType dataType, Lang
     }
 
     private DataStructure decodeStruct(MediaType dataType, SdmxFileSource source) throws IOException {
-        if (eventListener != SdmxManager.NO_OP_EVENT_LISTENER) {
-            eventListener.accept(source, "Decoding structure from '" + source.getData() + "' with data type '" + dataType + "'");
+        if (listener != null) {
+            listener.accept(source, SDMX_DECODER_MARKER, "Decoding structure from '" + source.getData() + "' with data type '" + dataType + "'");
         }
         return getStructDecoder(dataType)
                 .parseFile(source.getData());
diff --git a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/XmlFileClient.java b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/XmlFileClient.java
index c52592aec..4179b9896 100644
--- a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/XmlFileClient.java
+++ b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/XmlFileClient.java
@@ -21,8 +21,8 @@
 import nbbrd.io.xml.Xml;
 import org.checkerframework.checker.nullness.qual.Nullable;
 import sdmxdl.DataStructure;
+import sdmxdl.EventListener;
 import sdmxdl.LanguagePriorityList;
-import sdmxdl.SdmxManager;
 import sdmxdl.Series;
 import sdmxdl.file.SdmxFileSource;
 import sdmxdl.format.DataCursor;
@@ -36,7 +36,6 @@
 
 import java.io.FileNotFoundException;
 import java.io.IOException;
-import java.util.function.BiConsumer;
 import java.util.function.Supplier;
 import java.util.stream.Stream;
 
@@ -58,8 +57,7 @@ public class XmlFileClient implements FileClient {
     @Nullable
     private final Supplier<ObsParser> obsFactory;
 
-    @lombok.NonNull
-    BiConsumer<? super SdmxFileSource, ? super String> eventListener;
+    private final @Nullable EventListener<? super SdmxFileSource> listener;
 
     @Override
     public @NonNull Marker getMarker() {
@@ -83,8 +81,8 @@ public void testClient() throws IOException {
 
     @Override
     public @NonNull Stream<Series> loadData(@NonNull FileInfo info, @NonNull DataRef dataRef) throws IOException {
-        if (eventListener != SdmxManager.NO_OP_EVENT_LISTENER) {
-            eventListener.accept(source, "Loading data from file '" + source.getData() + "'");
+        if (listener != null) {
+            listener.accept(source, FILE_CLIENT_MARKER, "Loading data from file '" + source.getData() + "'");
         }
         return dataRef.getQuery().execute(
                 getDataSupplier(info.getDataType(), info.getStructure())
diff --git a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/readers/XmlReader.java b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/readers/XmlReader.java
index afb3746b3..20af5430c 100644
--- a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/readers/XmlReader.java
+++ b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/file/readers/XmlReader.java
@@ -43,9 +43,9 @@ private FileClient getClient(SdmxFileSource source, FileContext context) throws
         FileClient client = new XmlFileClient(
                 source,
                 context.getLanguages(),
-                new XmlDecoder(context.getEventListener()),
+                new XmlDecoder(context.getOnEvent()),
                 ObsParser::newDefault,
-                context.getEventListener()
+                context.getOnEvent()
         );
         return CachedFileClient.of(client, context.getCache(source), source, context.getLanguages());
     }
diff --git a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/RiHttpUtils.java b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/RiHttpUtils.java
index 2d0f3268f..51791af11 100644
--- a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/RiHttpUtils.java
+++ b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/RiHttpUtils.java
@@ -27,8 +27,9 @@
 import nbbrd.io.text.Property;
 import org.checkerframework.checker.nullness.qual.Nullable;
 import sdmxdl.About;
+import sdmxdl.EventListener;
 import sdmxdl.LanguagePriorityList;
-import sdmxdl.SdmxManager;
+import sdmxdl.Marker;
 import sdmxdl.provider.web.WebEvents;
 import sdmxdl.web.Network;
 import sdmxdl.web.SdmxWebSource;
@@ -43,7 +44,7 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.Objects;
-import java.util.function.BiConsumer;
+import java.util.function.Consumer;
 import java.util.function.Supplier;
 
 import static sdmxdl.provider.web.WebProperties.*;
@@ -105,8 +106,8 @@ private static DumpingClient newDumpingClient(HttpContext context, HttpClient cl
                 .sslSocketFactory(() -> network.getSSLFactory().getSSLSocketFactory())
                 .hostnameVerifier(() -> network.getSSLFactory().getHostnameVerifier())
                 .urlConnectionFactory(network::getURLConnectionFactory)
-                .listener(new RiHttpEventListener(source, context.getEventListener()))
-                .authenticator(new RiHttpAuthenticator(source, context.getAuthenticators(), context.getEventListener()))
+                .listener(context.getOnEvent() != null ? new RiHttpEventListener(context.getOnEvent().asConsumer(source, RI_HTTP_MARKER)) : HttpEventListener.noOp())
+                .authenticator(new RiHttpAuthenticator(source, context.getAuthenticators(), context.getOnEvent()))
                 .userAgent(HTTP_AGENT.get(System.getProperties()))
                 .build();
     }
@@ -114,49 +115,35 @@ private static DumpingClient newDumpingClient(HttpContext context, HttpClient cl
     @lombok.AllArgsConstructor
     private static final class RiHttpEventListener implements HttpEventListener {
 
-        @lombok.NonNull
-        private final SdmxWebSource source;
-
-        @lombok.NonNull
-        private final BiConsumer<? super SdmxWebSource, ? super String> listener;
+        private final @NonNull Consumer<CharSequence> listener;
 
         @Override
         public void onOpen(@NonNull HttpRequest request, @NonNull Proxy proxy, @NonNull HttpAuthScheme scheme) {
-            if (listener != SdmxManager.NO_OP_EVENT_LISTENER) {
-                String message = WebEvents.onQuery(request.getMethod().name(), request.getQuery(), proxy);
-                if (!HttpAuthScheme.NONE.equals(scheme)) {
-                    message += " with auth '" + scheme.name() + "'";
-                }
-                listener.accept(source, message);
+            String message = WebEvents.onQuery(request.getMethod().name(), request.getQuery(), proxy);
+            if (!HttpAuthScheme.NONE.equals(scheme)) {
+                message += " with auth '" + scheme.name() + "'";
             }
+            listener.accept(message);
         }
 
         @Override
         public void onSuccess(@NonNull Supplier<String> contentType) {
-            if (listener != SdmxManager.NO_OP_EVENT_LISTENER) {
-                listener.accept(source, String.format(Locale.ROOT, "Parsing '%s' content-type", contentType.get()));
-            }
+            listener.accept(String.format(Locale.ROOT, "Parsing '%s' content-type", contentType.get()));
         }
 
         @Override
         public void onRedirection(@NonNull URL oldUrl, @NonNull URL newUrl) {
-            if (listener != SdmxManager.NO_OP_EVENT_LISTENER) {
-                listener.accept(source, WebEvents.onRedirection(oldUrl, newUrl));
-            }
+            listener.accept(WebEvents.onRedirection(oldUrl, newUrl));
         }
 
         @Override
         public void onUnauthorized(@NonNull URL url, @NonNull HttpAuthScheme oldScheme, @NonNull HttpAuthScheme newScheme) {
-            if (listener != SdmxManager.NO_OP_EVENT_LISTENER) {
-                listener.accept(source, String.format(Locale.ROOT, "Authenticating %s with '%s'", url, newScheme.name()));
-            }
+            listener.accept(String.format(Locale.ROOT, "Authenticating %s with '%s'", url, newScheme.name()));
         }
 
         @Override
         public void onEvent(@NonNull String message) {
-            if (listener != SdmxManager.NO_OP_EVENT_LISTENER) {
-                listener.accept(source, message);
-            }
+            listener.accept(message);
         }
     }
 
@@ -169,8 +156,7 @@ private static final class RiHttpAuthenticator implements HttpAuthenticator {
         @lombok.NonNull
         private final List<WebAuthenticator> authenticators;
 
-        @lombok.NonNull
-        private final BiConsumer<? super SdmxWebSource, ? super String> listener;
+        private final @Nullable EventListener<? super SdmxWebSource> listener;
 
         @Override
         public @Nullable PasswordAuthentication getPasswordAuthentication(URL url) {
@@ -201,7 +187,9 @@ private PasswordAuthentication getPasswordAuthentication(WebAuthenticator authen
             try {
                 return authenticator.getPasswordAuthentication(source);
             } catch (IOException ex) {
-                listener.accept(source, "Failed to get password authentication: " + ex.getMessage());
+                if (listener != null) {
+                    listener.accept(source, RI_HTTP_MARKER, "Failed to get password authentication: " + ex.getMessage());
+                }
                 return null;
             }
         }
@@ -210,8 +198,12 @@ private void invalidate(WebAuthenticator authenticator) {
             try {
                 authenticator.invalidate(source);
             } catch (IOException ex) {
-                listener.accept(source, "Failed to invalidate password authentication: " + ex.getMessage());
+                if (listener != null) {
+                    listener.accept(source, RI_HTTP_MARKER, "Failed to invalidate password authentication: " + ex.getMessage());
+                }
             }
         }
     }
+
+    public static final Marker RI_HTTP_MARKER = Marker.parse("RI_HTTP");
 }
diff --git a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/drivers/FileDriver.java b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/drivers/FileDriver.java
index 4b67d7ca6..2298d0f9f 100644
--- a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/drivers/FileDriver.java
+++ b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/drivers/FileDriver.java
@@ -10,8 +10,8 @@
 import org.checkerframework.checker.nullness.qual.Nullable;
 import sdmxdl.Connection;
 import sdmxdl.DataRepository;
-import sdmxdl.ext.SdmxSourceConsumer;
-import sdmxdl.web.spi.WebCaching;
+import sdmxdl.ErrorListener;
+import sdmxdl.EventListener;
 import sdmxdl.file.FileCache;
 import sdmxdl.file.SdmxFileManager;
 import sdmxdl.file.SdmxFileSource;
@@ -19,6 +19,7 @@
 import sdmxdl.provider.web.WebDriverSupport;
 import sdmxdl.web.SdmxWebSource;
 import sdmxdl.web.WebCache;
+import sdmxdl.web.spi.WebCaching;
 import sdmxdl.web.spi.WebContext;
 import sdmxdl.web.spi.WebDriver;
 
@@ -52,8 +53,8 @@ public final class FileDriver implements WebDriver {
         return fileManager
                 .toBuilder()
                 .languages(context.getLanguages())
-                .eventListener((fileSource, message) -> context.getEventListener().accept(source, message))
-                .caching(new FileCachingAdapter(source, context.getCaching(), context.getEventListener()))
+                .onEvent(context.getOnEvent() != null ? (fileSource, marker, message) -> context.getOnEvent().accept(source, marker, message) : null)
+                .caching(new FileCachingAdapter(context.getCaching(), source, context.getOnEvent(), context.getOnError()))
                 .build()
                 .getConnection(toFileSource(source));
     }
@@ -61,11 +62,13 @@ public final class FileDriver implements WebDriver {
     @lombok.AllArgsConstructor
     private static final class FileCachingAdapter implements FileCaching {
 
+        private final @NonNull WebCaching delegate;
+
         private final @NonNull SdmxWebSource webSource;
 
-        private final @NonNull WebCaching delegate;
+        private final @Nullable EventListener<? super SdmxWebSource> onWebEvent;
 
-        private final @NonNull SdmxSourceConsumer<? super SdmxWebSource, ? super String> webListener;
+        private final @Nullable ErrorListener<? super SdmxWebSource> onWebError;
 
         @Override
         public @NonNull String getFileCachingId() {
@@ -78,8 +81,8 @@ public int getFileCachingRank() {
         }
 
         @Override
-        public @NonNull FileCache getFileCache(@NonNull SdmxFileSource ignoreSource, @NonNull SdmxSourceConsumer<? super SdmxFileSource, ? super String> ignoreEvent) {
-            return new FileCacheAdapter(delegate.getWebCache(webSource, webListener));
+        public @NonNull FileCache getFileCache(@NonNull SdmxFileSource ignoreSource, @Nullable EventListener<? super SdmxFileSource> ignoreEvent, @Nullable ErrorListener<? super SdmxFileSource> ignoreError) {
+            return new FileCacheAdapter(delegate.getWebCache(webSource, onWebEvent, onWebError));
         }
 
         @Override
diff --git a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/drivers/StatCanDriver.java b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/drivers/StatCanDriver.java
index eae09c75c..4af4b0f82 100644
--- a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/drivers/StatCanDriver.java
+++ b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/drivers/StatCanDriver.java
@@ -14,6 +14,7 @@
 import nbbrd.io.net.MediaType;
 import nbbrd.service.ServiceProvider;
 import sdmxdl.*;
+import sdmxdl.provider.Marker;
 import sdmxdl.web.WebCache;
 import sdmxdl.format.DataCursor;
 import sdmxdl.format.ObsParser;
diff --git a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/monitors/UptimeRobotMonitoring.java b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/monitors/UptimeRobotMonitoring.java
index 2246ebcd2..18881c7be 100644
--- a/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/monitors/UptimeRobotMonitoring.java
+++ b/sdmx-dl-provider-ri/src/main/java/internal/sdmxdl/provider/ri/web/monitors/UptimeRobotMonitoring.java
@@ -7,7 +7,6 @@
 import nbbrd.io.xml.Stax;
 import nbbrd.io.xml.Xml;
 import nbbrd.service.ServiceProvider;
-import sdmxdl.SdmxManager;
 import sdmxdl.provider.web.WebEvents;
 import sdmxdl.provider.web.WebMonitors;
 import sdmxdl.web.*;
@@ -100,8 +99,8 @@ private static <T> T post(URL url, String query, IOFunction<Reader, T> factory,
         Network network = context.getNetwork(source);
         Proxy proxy = network.getProxySelector().select(toURI(url)).stream().findFirst().orElse(Proxy.NO_PROXY);
 
-        if (context.getEventListener() != SdmxManager.NO_OP_EVENT_LISTENER) {
-            context.getEventListener().accept(source, WebEvents.onQuery(url, proxy));
+        if (context.getOnEvent() != null) {
+            context.getOnEvent().accept(source, WEB_MONITORING_MARKER, WebEvents.onQuery(url, proxy));
         }
 
         HttpURLConnection conn = (HttpURLConnection) url.openConnection(proxy);
diff --git a/sdmx-dl-provider-ri/src/test/java/internal/sdmxdl/provider/ri/file/XmlFileClientTest.java b/sdmx-dl-provider-ri/src/test/java/internal/sdmxdl/provider/ri/file/XmlFileClientTest.java
index 3a54cd2cb..4f12f6d57 100644
--- a/sdmx-dl-provider-ri/src/test/java/internal/sdmxdl/provider/ri/file/XmlFileClientTest.java
+++ b/sdmx-dl-provider-ri/src/test/java/internal/sdmxdl/provider/ri/file/XmlFileClientTest.java
@@ -48,7 +48,7 @@ public void testCompactData21(@TempDir Path temp) throws IOException {
         SdmxXmlSources.OTHER_COMPACT21.copyTo(compact21);
 
         SdmxFileSource source = sourceOf(compact21);
-        FileClient x = new XmlFileClient(source, ANY, DECODER, null, SdmxManager.NO_OP_EVENT_LISTENER);
+        FileClient x = new XmlFileClient(source, ANY, DECODER, null, null);
 
         FileInfo info = x.decode();
 
@@ -95,6 +95,6 @@ public static SdmxFileSource sourceOf(File compact21) {
         return SdmxFileSource.builder().data(compact21).build();
     }
 
-    public static final SdmxDecoder DECODER = new XmlDecoder(SdmxManager.NO_OP_EVENT_LISTENER);
+    public static final SdmxDecoder DECODER = new XmlDecoder(null);
     public static final Dataflow DATAFLOW = Dataflow.builder().ref(DataflowRef.parse("data")).structureRef(DataStructureRef.parse("xyz")).name("label").build();
 }
diff --git a/sdmx-dl-provider-ri/src/test/java/internal/sdmxdl/provider/ri/web/RiHttpUtilsTest.java b/sdmx-dl-provider-ri/src/test/java/internal/sdmxdl/provider/ri/web/RiHttpUtilsTest.java
index 9f00a1ea1..905668131 100644
--- a/sdmx-dl-provider-ri/src/test/java/internal/sdmxdl/provider/ri/web/RiHttpUtilsTest.java
+++ b/sdmx-dl-provider-ri/src/test/java/internal/sdmxdl/provider/ri/web/RiHttpUtilsTest.java
@@ -5,6 +5,7 @@
 import lombok.NonNull;
 import nbbrd.io.net.MediaType;
 import org.junit.jupiter.api.Test;
+import sdmxdl.Marker;
 import sdmxdl.web.SdmxWebSource;
 import sdmxdl.web.spi.WebContext;
 import tests.sdmxdl.web.WebDriverAssert;
@@ -56,7 +57,7 @@ public void testListener() throws MalformedURLException {
 
         WebContext webContext = WebContext
                 .builder()
-                .eventListener(events::onSourceEvent)
+                .onEvent(events::onSourceEvent)
                 .build();
 
         HttpEventListener x = RiHttpUtils.newContext(source, webContext).getListener();
@@ -124,8 +125,8 @@ public List<Event> pop() {
             return result;
         }
 
-        public void onSourceEvent(@NonNull SdmxWebSource source, @NonNull String message) {
-            events.add(new Event(source, message));
+        public void onSourceEvent(@NonNull SdmxWebSource source, @NonNull Marker marker, @NonNull CharSequence message) {
+            events.add(new Event(source, message.toString()));
         }
     }
 }
\ No newline at end of file