diff --git a/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/impl/StubScopeModel.java b/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/impl/StubScopeModel.java
index 4f34e64de08..f2ad0b409cc 100644
--- a/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/impl/StubScopeModel.java
+++ b/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/impl/StubScopeModel.java
@@ -10,6 +10,7 @@
 import java.util.List;
 import java.util.Set;
 
+import org.hibernate.search.engine.backend.types.converter.spi.DocumentIdentifierValueConverter;
 import org.hibernate.search.util.common.impl.CollectionHelper;
 import org.hibernate.search.util.impl.integrationtest.common.stub.backend.document.model.StubIndexSchemaNode;
 import org.hibernate.search.util.impl.integrationtest.common.stub.backend.types.converter.impl.StubFieldConverter;
@@ -55,6 +56,18 @@ else if ( !result.isConvertIndexToProjectionCompatibleWith( converter ) ) {
 		return result;
 	}
 
+	public DocumentIdentifierValueConverter<?> idDslConverter() {
+		for ( StubIndexSchemaNode index : rootSchemaNodes ) {
+			DocumentIdentifierValueConverter<?> converter = index.getIdDslConverter();
+
+			// there is no need to check the compatibility - this is a stub backend
+			if ( converter != null ) {
+				return converter;
+			}
+		}
+		return null;
+	}
+
 	private static List<StubIndexSchemaNode> getSchemaNodes(StubIndexSchemaNode root, String[] pathComponents) {
 		List<StubIndexSchemaNode> parents;
 		List<StubIndexSchemaNode> children = CollectionHelper.asList( root );
diff --git a/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubFieldSearchProjection.java b/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubFieldSearchProjection.java
index cea1792b41c..1b1c08d13bd 100644
--- a/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubFieldSearchProjection.java
+++ b/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubFieldSearchProjection.java
@@ -23,7 +23,7 @@ class StubFieldSearchProjection<T> implements StubSearchProjection<T> {
 	public Object extract(ProjectionHitMapper<?, ?> projectionHitMapper, Object projectionFromIndex,
 			StubSearchProjectionContext context) {
 		return converter.convertIndexToProjection(
-				projectionFromIndex, context.getFromDocumentFieldValueConvertContext()
+				projectionFromIndex, context.fromDocumentFieldValueConvertContext()
 		);
 	}
 
diff --git a/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubIdSearchProjection.java b/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubIdSearchProjection.java
new file mode 100644
index 00000000000..320c1790fb4
--- /dev/null
+++ b/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubIdSearchProjection.java
@@ -0,0 +1,59 @@
+/*
+ * Hibernate Search, full-text search for your domain model
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
+ */
+package org.hibernate.search.util.impl.integrationtest.common.stub.backend.search.projection.impl;
+
+import org.hibernate.search.engine.backend.common.DocumentReference;
+import org.hibernate.search.engine.backend.types.converter.spi.DocumentIdentifierValueConverter;
+import org.hibernate.search.engine.search.loading.spi.LoadingResult;
+import org.hibernate.search.engine.search.loading.spi.ProjectionHitMapper;
+import org.hibernate.search.engine.search.projection.SearchProjection;
+import org.hibernate.search.engine.search.projection.spi.IdProjectionBuilder;
+
+public class StubIdSearchProjection<I> implements StubSearchProjection<I> {
+
+	private final DocumentIdentifierValueConverter<? extends I> identifierValueConverter;
+
+	private StubIdSearchProjection(DocumentIdentifierValueConverter<? extends I> identifierValueConverter) {
+		this.identifierValueConverter = identifierValueConverter;
+	}
+
+	@Override
+	public Object extract(ProjectionHitMapper<?, ?> projectionHitMapper, Object projectionFromIndex,
+			StubSearchProjectionContext context) {
+		return projectionFromIndex;
+	}
+
+	@SuppressWarnings("unchecked")
+	@Override
+	public I transform(LoadingResult<?, ?> loadingResult, Object extractedData,
+			StubSearchProjectionContext context) {
+		DocumentReference documentReference = (DocumentReference) extractedData;
+
+		context.fromDocumentFieldValueConvertContext();
+		return identifierValueConverter.convertToSource(
+				documentReference.id(), context.fromDocumentIdentifierValueConvertContext() );
+	}
+
+	public static class Builder<I> implements IdProjectionBuilder<I> {
+
+		private final StubSearchProjection<I> projection;
+
+		public Builder(DocumentIdentifierValueConverter<?> identifierValueConverter, Class<I> identifierType) {
+			// check expected identifier type:
+			identifierValueConverter.requiresType( identifierType );
+			@SuppressWarnings("uncheked") // just checked
+			DocumentIdentifierValueConverter<? extends I> casted = (DocumentIdentifierValueConverter<? extends I>) identifierValueConverter;
+
+			projection = new StubIdSearchProjection( casted );
+		}
+
+		@Override
+		public SearchProjection<I> build() {
+			return projection;
+		}
+	}
+}
diff --git a/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubSearchProjectionBuilderFactory.java b/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubSearchProjectionBuilderFactory.java
index c874b72c314..34d3b262afc 100644
--- a/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubSearchProjectionBuilderFactory.java
+++ b/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubSearchProjectionBuilderFactory.java
@@ -85,8 +85,7 @@ public <R> EntityReferenceProjectionBuilder<R> entityReference() {
 
 	@Override
 	public <I> IdProjectionBuilder<I> id(Class<I> identifierType) {
-		// TODO HSEARCH-4142 Support from this backend
-		return null;
+		return new StubIdSearchProjection.Builder<>( scopeModel.idDslConverter(), identifierType );
 	}
 
 	@Override
diff --git a/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubSearchProjectionContext.java b/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubSearchProjectionContext.java
index 9601f0e9f5b..469c3f1a0b3 100644
--- a/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubSearchProjectionContext.java
+++ b/util/internal/integrationtest/common/src/main/java/org/hibernate/search/util/impl/integrationtest/common/stub/backend/search/projection/impl/StubSearchProjectionContext.java
@@ -9,21 +9,28 @@
 import org.hibernate.search.engine.backend.types.converter.runtime.FromDocumentFieldValueConvertContext;
 import org.hibernate.search.engine.backend.types.converter.runtime.spi.FromDocumentFieldValueConvertContextImpl;
 import org.hibernate.search.engine.backend.session.spi.BackendSessionContext;
+import org.hibernate.search.engine.backend.types.converter.runtime.spi.FromDocumentIdentifierValueConvertContextImpl;
 
 public class StubSearchProjectionContext {
 
 	private final FromDocumentFieldValueConvertContext fromDocumentFieldValueConvertContext;
+	private final FromDocumentIdentifierValueConvertContextImpl fromDocumentIdentifierValueConvertContext;
 
 	private boolean hasFailedLoad = false;
 
 	public StubSearchProjectionContext(BackendSessionContext sessionContext) {
-		this.fromDocumentFieldValueConvertContext = new FromDocumentFieldValueConvertContextImpl( sessionContext );
+		fromDocumentFieldValueConvertContext = new FromDocumentFieldValueConvertContextImpl( sessionContext );
+		fromDocumentIdentifierValueConvertContext = new FromDocumentIdentifierValueConvertContextImpl( sessionContext );
 	}
 
-	FromDocumentFieldValueConvertContext getFromDocumentFieldValueConvertContext() {
+	FromDocumentFieldValueConvertContext fromDocumentFieldValueConvertContext() {
 		return fromDocumentFieldValueConvertContext;
 	}
 
+	FromDocumentIdentifierValueConvertContextImpl fromDocumentIdentifierValueConvertContext() {
+		return fromDocumentIdentifierValueConvertContext;
+	}
+
 	void reportFailedLoad() {
 		hasFailedLoad = true;
 	}