diff --git a/engines/base/src/main/java/org/alfresco/transform/base/TransformManager.java b/engines/base/src/main/java/org/alfresco/transform/base/TransformManager.java
index 1fd90612..89455da3 100644
--- a/engines/base/src/main/java/org/alfresco/transform/base/TransformManager.java
+++ b/engines/base/src/main/java/org/alfresco/transform/base/TransformManager.java
@@ -39,6 +39,11 @@ import java.util.Map;
  */
 public interface TransformManager
 {
+    /**
+     * @return the id of the request.
+     */
+    String getRequestId();
+
     /**
      * Allows a {@link CustomTransformer} to use a local source {@code File} rather than the supplied {@code InputStream}.
      * The file will be deleted once the request is completed. To avoid creating extra files, if a File has already
diff --git a/engines/base/src/main/java/org/alfresco/transform/base/messaging/MessagingConfig.java b/engines/base/src/main/java/org/alfresco/transform/base/messaging/MessagingConfig.java
index 276f942a..04a8a2fe 100644
--- a/engines/base/src/main/java/org/alfresco/transform/base/messaging/MessagingConfig.java
+++ b/engines/base/src/main/java/org/alfresco/transform/base/messaging/MessagingConfig.java
@@ -26,13 +26,8 @@
  */
 package org.alfresco.transform.base.messaging;
 
-import javax.jms.ConnectionFactory;
-import javax.jms.Queue;
-
 import org.alfresco.transform.messages.TransformRequestValidator;
 import org.apache.activemq.command.ActiveMQQueue;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.context.annotation.Bean;
@@ -45,6 +40,9 @@ import org.springframework.lang.NonNull;
 import org.springframework.messaging.handler.annotation.support.DefaultMessageHandlerMethodFactory;
 import org.springframework.transaction.PlatformTransactionManager;
 
+import javax.jms.ConnectionFactory;
+import javax.jms.Queue;
+
 /**
  * JMS and messaging configuration for the T-Engines. Contains the basic config in order to have the
  * T-Engine able to read from queues and send a reply back.
diff --git a/engines/base/src/main/java/org/alfresco/transform/base/registry/CustomTransformers.java b/engines/base/src/main/java/org/alfresco/transform/base/registry/CustomTransformers.java
index a4df1599..be1c35af 100644
--- a/engines/base/src/main/java/org/alfresco/transform/base/registry/CustomTransformers.java
+++ b/engines/base/src/main/java/org/alfresco/transform/base/registry/CustomTransformers.java
@@ -37,6 +37,7 @@ import java.util.Comparator;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 
 @Component
 public class CustomTransformers
@@ -48,8 +49,6 @@ public class CustomTransformers
 
     private final Map<String, CustomTransformer> customTransformersByName = new HashMap<>();
 
-    private CustomTransformer defaultCustomTransformer;
-
     @PostConstruct
     private void initCustomTransformersByName()
     {
@@ -61,19 +60,17 @@ public class CustomTransformers
             logger.info("Transformers:");
             customTransformers.stream()
                   .sorted(Comparator.comparing(CustomTransformer::getTransformerName))
-                  .map(customTransformer -> "  "+customTransformer.getTransformerName()).forEach(logger::info);
+                  .map(customTransformer -> customTransformer.getTransformerName())
+                  .filter(Objects::nonNull)
+                  .map(name -> "  "+name)
+                  .forEach(logger::info);
         }
     }
 
-    public void setDefaultCustomTransformer(CustomTransformer defaultCustomTransformer)
-    {
-        this.defaultCustomTransformer = defaultCustomTransformer;
-    }
-
     public CustomTransformer get(String name)
     {
         CustomTransformer customTransformer = customTransformersByName.get(name);
-        return customTransformer == null ? defaultCustomTransformer : customTransformer;
+        return customTransformer == null ? customTransformersByName.get(null) : customTransformer;
     }
 
     public void put(String name, CustomTransformer  customTransformer)
diff --git a/engines/base/src/main/java/org/alfresco/transform/base/transform/ProcessHandler.java b/engines/base/src/main/java/org/alfresco/transform/base/transform/ProcessHandler.java
index 010a7d6e..0f357c0c 100644
--- a/engines/base/src/main/java/org/alfresco/transform/base/transform/ProcessHandler.java
+++ b/engines/base/src/main/java/org/alfresco/transform/base/transform/ProcessHandler.java
@@ -108,6 +108,12 @@ abstract class ProcessHandler extends FragmentHandler
         super.init();
     }
 
+
+    public String getReference()
+    {
+        return reference;
+    }
+
     public void handleTransformRequest()
     {
         LogEntry.start();
diff --git a/engines/base/src/main/java/org/alfresco/transform/base/transform/TransformManagerImpl.java b/engines/base/src/main/java/org/alfresco/transform/base/transform/TransformManagerImpl.java
index f3a4dd1b..47efa34f 100644
--- a/engines/base/src/main/java/org/alfresco/transform/base/transform/TransformManagerImpl.java
+++ b/engines/base/src/main/java/org/alfresco/transform/base/transform/TransformManagerImpl.java
@@ -71,6 +71,11 @@ public class TransformManagerImpl implements TransformManager
         this.processHandler = processHandler;
     }
 
+    @Override public String getRequestId()
+    {
+        return processHandler.getReference();
+    }
+
     public InputStream setInputStream(InputStream inputStream)
     {
         this.inputStream = inputStream;
@@ -130,14 +135,13 @@ public class TransformManagerImpl implements TransformManager
         return targetFile;
     }
 
-    File setTargetFile(File targetFile)
+    public void setTargetFile(File targetFile)
     {
         this.targetFile = targetFile;
         if (startedWithTargetFile == null)
         {
             startedWithTargetFile = true;
         }
-        return targetFile;
     }
 
     public void keepTargetFile()
@@ -179,7 +183,7 @@ public class TransformManagerImpl implements TransformManager
     {
         if (targetFile != null)
         {
-            if (startedWithTargetFile == false)
+            if (!startedWithTargetFile)
             {
                 FileManager.copyFileToOutputStream(targetFile, outputStreamLengthRecorder);
             }
diff --git a/engines/base/src/main/java/org/alfresco/transform/base/util/CustomTransformerFileAdaptor.java b/engines/base/src/main/java/org/alfresco/transform/base/util/CustomTransformerFileAdaptor.java
index e645f5cd..be166ca2 100644
--- a/engines/base/src/main/java/org/alfresco/transform/base/util/CustomTransformerFileAdaptor.java
+++ b/engines/base/src/main/java/org/alfresco/transform/base/util/CustomTransformerFileAdaptor.java
@@ -47,9 +47,9 @@ public interface CustomTransformerFileAdaptor extends CustomTransformer
     {
         File sourceFile = transformManager.createSourceFile();
         File targetFile = transformManager.createTargetFile();
-        transform(sourceMimetype, targetMimetype, transformOptions, sourceFile, targetFile);
+        transform(sourceMimetype, targetMimetype, transformOptions, sourceFile, targetFile, transformManager);
     }
 
     void transform(String sourceMimetype, String targetMimetype, Map<String, String> transformOptions,
-            File sourceFile, File targetFile) throws Exception;
+            File sourceFile, File targetFile, TransformManager transformManager) throws Exception;
 }
\ No newline at end of file
diff --git a/engines/base/src/main/resources/templates/test.html b/engines/base/src/main/resources/templates/test.html
index c25b4d3d..8325068c 100644
--- a/engines/base/src/main/resources/templates/test.html
+++ b/engines/base/src/main/resources/templates/test.html
@@ -8,7 +8,7 @@
                 <tr><td><div style="text-align:right">directAccessUrl</div></td><td><input type="text" name="directAccessUrl"/></td></tr>
                 <tr><td><div style="text-align:right">sourceMimetype</div></td><td><input type="text" name="sourceMimetype" value="" /></td>
                   <td><select name="_sourceMimetype">
-                    <option value="" >-- file extension --</option>
+                    <option value="" >-- by file extension --</option>
                     <option value="image/jpeg" >jpg</option>
                     <option value="image/png">png</option>
                     <option value="application/pdf">pdf</option>
@@ -19,7 +19,7 @@
                   </select></td></tr>
                 <tr><td><div style="text-align:right">targetMimetype</div></td><td><input type="text" name="targetMimetype" value="" /></td>
                     <td><select name="_targetMimetype">
-                        <option value="" >-- file extension --</option>
+                        <option value="" >-- by file extension --</option>
                         <option value="image/jpeg" >jpg</option>
                         <option value="image/png">png</option>
                         <option value="application/pdf">pdf</option>
diff --git a/engines/imagemagick/src/main/java/org/alfresco/transform/imagemagick/transformers/ImageMagickTransformer.java b/engines/imagemagick/src/main/java/org/alfresco/transform/imagemagick/transformers/ImageMagickTransformer.java
index 1dcd4a33..52f9518c 100644
--- a/engines/imagemagick/src/main/java/org/alfresco/transform/imagemagick/transformers/ImageMagickTransformer.java
+++ b/engines/imagemagick/src/main/java/org/alfresco/transform/imagemagick/transformers/ImageMagickTransformer.java
@@ -37,8 +37,6 @@ import org.springframework.stereotype.Component;
 
 import javax.annotation.PostConstruct;
 import java.io.File;
-import java.io.InputStream;
-import java.io.OutputStream;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -152,7 +150,7 @@ public class ImageMagickTransformer extends AbstractCommandExecutor implements C
 
     @Override
     public void transform(String sourceMimetype, String targetMimetype, Map<String, String> transformOptions,
-                          File sourceFile, File targetFile) throws TransformException
+                          File sourceFile, File targetFile, TransformManager transformManager) throws TransformException
     {
         final String options = ImageMagickOptionsBuilder
                 .builder()
diff --git a/engines/libreoffice/src/main/java/org/alfresco/transform/libreoffice/transformers/LibreOfficeTransformer.java b/engines/libreoffice/src/main/java/org/alfresco/transform/libreoffice/transformers/LibreOfficeTransformer.java
index d0eebe3a..237893e7 100644
--- a/engines/libreoffice/src/main/java/org/alfresco/transform/libreoffice/transformers/LibreOfficeTransformer.java
+++ b/engines/libreoffice/src/main/java/org/alfresco/transform/libreoffice/transformers/LibreOfficeTransformer.java
@@ -47,8 +47,6 @@ import org.springframework.stereotype.Component;
 import javax.annotation.PostConstruct;
 import java.io.File;
 import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
 import java.io.Serializable;
 import java.util.Map;
 
@@ -133,7 +131,7 @@ public class LibreOfficeTransformer implements JavaExecutor, CustomTransformerFi
 
     @Override
     public void transform(String sourceMimetype, String targetMimetype, Map<String, String> transformOptions,
-                          File sourceFile, File targetFile)
+                          File sourceFile, File targetFile, TransformManager transformManager)
     {
         call(sourceFile, targetFile);
     }
diff --git a/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/AppleIWorksContentTransformer.java b/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/AppleIWorksContentTransformer.java
index 81e80c96..d6b9de4f 100644
--- a/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/AppleIWorksContentTransformer.java
+++ b/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/AppleIWorksContentTransformer.java
@@ -39,8 +39,6 @@ import java.io.BufferedInputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
 import java.nio.file.Files;
 import java.nio.file.StandardCopyOption;
 import java.util.List;
@@ -86,7 +84,7 @@ public class AppleIWorksContentTransformer implements CustomTransformerFileAdapt
 
     @Override
     public void transform(String sourceMimetype, String targetMimetype, Map<String, String> transformOptions,
-                          File sourceFile, File targetFile)
+                          File sourceFile, File targetFile, TransformManager transformManager)
     {
         logger.debug("Performing IWorks to jpeg transform with sourceMimetype={} targetMimetype={}",
             sourceMimetype, targetMimetype);
diff --git a/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/EMLTransformer.java b/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/EMLTransformer.java
index 5ec68656..b2de56d3 100644
--- a/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/EMLTransformer.java
+++ b/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/EMLTransformer.java
@@ -46,7 +46,6 @@ import java.io.FileOutputStream;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.io.Writer;
 import java.util.Map;
@@ -84,7 +83,7 @@ public class EMLTransformer implements CustomTransformerFileAdaptor
 
     @Override
     public void transform(String sourceMimetype, String targetMimetype, Map<String, String> transformOptions,
-                          File sourceFile, File targetFile) throws Exception
+                          File sourceFile, File targetFile, TransformManager transformManager) throws Exception
     {
         logger.debug("Performing RFC822 to text transform.");
         // Use try with resource
diff --git a/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/HtmlParserContentTransformer.java b/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/HtmlParserContentTransformer.java
index 3f625308..46bee139 100644
--- a/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/HtmlParserContentTransformer.java
+++ b/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/HtmlParserContentTransformer.java
@@ -26,6 +26,7 @@
  */
 package org.alfresco.transform.misc.transformers;
 
+import org.alfresco.transform.base.TransformManager;
 import org.alfresco.transform.base.util.CustomTransformerFileAdaptor;
 import org.htmlparser.Parser;
 import org.htmlparser.beans.StringBean;
@@ -88,7 +89,7 @@ public class HtmlParserContentTransformer implements CustomTransformerFileAdapto
     @Override
     public void transform(final String sourceMimetype, final String targetMimetype,
                           final Map<String, String> transformOptions,
-                          final File sourceFile, final File targetFile) throws Exception
+                          final File sourceFile, final File targetFile, TransformManager transformManager) throws Exception
     {
         String sourceEncoding = transformOptions.get(SOURCE_ENCODING);
         checkEncodingParameter(sourceEncoding, SOURCE_ENCODING);
diff --git a/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/OOXMLThumbnailContentTransformer.java b/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/OOXMLThumbnailContentTransformer.java
index 31022f85..779a6296 100644
--- a/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/OOXMLThumbnailContentTransformer.java
+++ b/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/OOXMLThumbnailContentTransformer.java
@@ -40,7 +40,6 @@ import org.springframework.stereotype.Component;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.OutputStream;
 import java.nio.file.Files;
 import java.nio.file.StandardCopyOption;
 import java.util.Map;
@@ -70,7 +69,7 @@ public class OOXMLThumbnailContentTransformer implements CustomTransformerFileAd
 
     @Override
     public void transform(final String sourceMimetype, final String targetMimetype, final Map<String, String> parameters,
-                          final File sourceFile, final File targetFile) throws Exception
+                          final File sourceFile, final File targetFile, TransformManager transformManager) throws Exception
     {
         if (logger.isDebugEnabled())
         {
diff --git a/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/StringExtractingContentTransformer.java b/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/StringExtractingContentTransformer.java
index a466558f..65147efe 100644
--- a/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/StringExtractingContentTransformer.java
+++ b/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/StringExtractingContentTransformer.java
@@ -26,6 +26,7 @@
  */
 package org.alfresco.transform.misc.transformers;
 
+import org.alfresco.transform.base.TransformManager;
 import org.alfresco.transform.base.util.CustomTransformerFileAdaptor;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -80,7 +81,7 @@ public class StringExtractingContentTransformer implements CustomTransformerFile
      */
     @Override
     public void transform(final String sourceMimetype, final String targetMimetype, final Map<String, String> transformOptions,
-                          final File sourceFile, final File targetFile) throws Exception
+                          final File sourceFile, final File targetFile, TransformManager transformManager) throws Exception
     {
         String sourceEncoding = transformOptions.get(SOURCE_ENCODING);
         String targetEncoding = transformOptions.get(TARGET_ENCODING);
diff --git a/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/TextToPdfContentTransformer.java b/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/TextToPdfContentTransformer.java
index 2a4a96a5..9cc8ec70 100644
--- a/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/TextToPdfContentTransformer.java
+++ b/engines/misc/src/main/java/org/alfresco/transform/misc/transformers/TextToPdfContentTransformer.java
@@ -116,7 +116,7 @@ public class TextToPdfContentTransformer implements CustomTransformerFileAdaptor
     @Override
     public void transform(final String sourceMimetype, final String targetMimetype, final Map<String,
                           String> transformOptions,
-                          final File sourceFile, final File targetFile) throws Exception
+                          final File sourceFile, final File targetFile, TransformManager transformManager) throws Exception
     {
         String sourceEncoding = transformOptions.get(SOURCE_ENCODING);
         String stringPageLimit = transformOptions.get(PAGE_LIMIT);
diff --git a/engines/misc/src/test/java/org/alfresco/transform/misc/transformers/HtmlParserContentTransformerTest.java b/engines/misc/src/test/java/org/alfresco/transform/misc/transformers/HtmlParserContentTransformerTest.java
index 7a275886..c778e249 100644
--- a/engines/misc/src/test/java/org/alfresco/transform/misc/transformers/HtmlParserContentTransformerTest.java
+++ b/engines/misc/src/test/java/org/alfresco/transform/misc/transformers/HtmlParserContentTransformerTest.java
@@ -81,7 +81,7 @@ public class HtmlParserContentTransformerTest
 
             Map<String, String> parameters = new HashMap<>();
             parameters.put(SOURCE_ENCODING, "ISO-8859-1");
-            transformer.transform(SOURCE_MIMETYPE, TARGET_MIMETYPE, parameters, tmpS, tmpD);
+            transformer.transform(SOURCE_MIMETYPE, TARGET_MIMETYPE, parameters, tmpS, tmpD, transformManager);
 
             assertEquals(expected, readFromFile(tmpD, "UTF-8"));
             tmpS.delete();
@@ -94,7 +94,7 @@ public class HtmlParserContentTransformerTest
             tmpD = File.createTempFile("AlfrescoTestTarget_", ".txt");
             parameters = new HashMap<>();
             parameters.put(SOURCE_ENCODING, "UTF-8");
-            transformer.transform(SOURCE_MIMETYPE, TARGET_MIMETYPE, parameters, tmpS, tmpD);
+            transformer.transform(SOURCE_MIMETYPE, TARGET_MIMETYPE, parameters, tmpS, tmpD, transformManager);
             assertEquals(expected, readFromFile(tmpD, "UTF-8"));
             tmpS.delete();
             tmpD.delete();
@@ -106,7 +106,7 @@ public class HtmlParserContentTransformerTest
             tmpD = File.createTempFile("AlfrescoTestTarget_", ".txt");
             parameters = new HashMap<>();
             parameters.put(SOURCE_ENCODING, "UTF-16");
-            transformer.transform(SOURCE_MIMETYPE, TARGET_MIMETYPE, parameters, tmpS, tmpD);
+            transformer.transform(SOURCE_MIMETYPE, TARGET_MIMETYPE, parameters, tmpS, tmpD, transformManager);
             assertEquals(expected, readFromFile(tmpD, "UTF-8"));
             tmpS.delete();
             tmpD.delete();
@@ -131,7 +131,7 @@ public class HtmlParserContentTransformerTest
 
             parameters = new HashMap<>();
             parameters.put(SOURCE_ENCODING, "ISO-8859-1");
-            transformer.transform(SOURCE_MIMETYPE, TARGET_MIMETYPE, parameters, tmpS, tmpD);
+            transformer.transform(SOURCE_MIMETYPE, TARGET_MIMETYPE, parameters, tmpS, tmpD, transformManager);
             assertEquals(expected, readFromFile(tmpD, "UTF-8"));
             tmpS.delete();
             tmpD.delete();
diff --git a/engines/misc/src/test/java/org/alfresco/transform/misc/transformers/TextToPdfContentTransformerTest.java b/engines/misc/src/test/java/org/alfresco/transform/misc/transformers/TextToPdfContentTransformerTest.java
index eea70765..d880cf05 100644
--- a/engines/misc/src/test/java/org/alfresco/transform/misc/transformers/TextToPdfContentTransformerTest.java
+++ b/engines/misc/src/test/java/org/alfresco/transform/misc/transformers/TextToPdfContentTransformerTest.java
@@ -201,7 +201,7 @@ public class TextToPdfContentTransformerTest
         Map<String, String> parameters = new HashMap<>();
         parameters.put(PAGE_LIMIT, pageLimit);
         parameters.put(SOURCE_ENCODING, encoding);
-        transformer.transform("text/plain", "application/pdf", parameters, sourceFile, targetFile);
+        transformer.transform("text/plain", "application/pdf", parameters, sourceFile, targetFile, transformManager);
 
         // Read back in the PDF and check it
         PDDocument doc = PDDocument.load(targetFile);
diff --git a/engines/pdfrenderer/src/main/java/org/alfresco/transform/pdfrenderer/transformers/PdfRendererTransformer.java b/engines/pdfrenderer/src/main/java/org/alfresco/transform/pdfrenderer/transformers/PdfRendererTransformer.java
index cba5d71e..6cc12c81 100644
--- a/engines/pdfrenderer/src/main/java/org/alfresco/transform/pdfrenderer/transformers/PdfRendererTransformer.java
+++ b/engines/pdfrenderer/src/main/java/org/alfresco/transform/pdfrenderer/transformers/PdfRendererTransformer.java
@@ -37,8 +37,6 @@ import org.springframework.stereotype.Component;
 
 import javax.annotation.PostConstruct;
 import java.io.File;
-import java.io.InputStream;
-import java.io.OutputStream;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -105,7 +103,7 @@ public class PdfRendererTransformer extends AbstractCommandExecutor implements C
 
     @Override
     public void transform(String sourceMimetype, String targetMimetype, Map<String, String> transformOptions,
-                          File sourceFile, File targetFile) throws TransformException
+                          File sourceFile, File targetFile, TransformManager transformManager) throws TransformException
     {
         final String options = PdfRendererOptionsBuilder
                 .builder()
diff --git a/model/src/main/java/org/alfresco/transform/common/RepositoryClientData.java b/model/src/main/java/org/alfresco/transform/common/RepositoryClientData.java
index 2507454f..f7f0d136 100644
--- a/model/src/main/java/org/alfresco/transform/common/RepositoryClientData.java
+++ b/model/src/main/java/org/alfresco/transform/common/RepositoryClientData.java
@@ -28,14 +28,20 @@ import java.util.stream.Stream;
  * The client data supplied and echoed back to content repository (the client). May be modified to include
  * TransformerDebug.
  */
-public class RepositoryClientData
-{
+public class RepositoryClientData {
     public static final String CLIENT_DATA_SEPARATOR = "\u23D0";
     public static final String DEBUG_SEPARATOR = "\u23D1";
-    static final String REPO_ID = "Repo";
+    public static final String REPO_ID = "Repo";
     public static final String DEBUG = "debug:";
 
+    private static final int REPO_INDEX = 0;
+    private static final int RENDITION_INDEX = 2;
+    private static final int REQUEST_ID_INDEX = 6;
+    private static final int DEBUG_INDEX = 9;
+    private static final int EXPECTED_ELEMENTS = 10;
+
     private final String origClientData;
+
     private final String[] split;
 
     public RepositoryClientData(String clientData)
@@ -46,53 +52,102 @@ public class RepositoryClientData
 
     private boolean isRepositoryClientData()
     {
-        return split != null && split.length == 10 && split[0].startsWith(REPO_ID);
+        return split != null && split.length == EXPECTED_ELEMENTS && split[REPO_INDEX].startsWith(REPO_ID);
     }
 
     public String getAcsVersion()
     {
-        return isRepositoryClientData() ? split[0].substring(REPO_ID.length()) : "";
+        return isRepositoryClientData() ? split[REPO_INDEX].substring(REPO_ID.length()) : "";
     }
 
     public int getRequestId()
     {
-        try
-        {
-            return isRepositoryClientData() ? Integer.parseInt(split[6]) : -1;
-        }
-        catch (NumberFormatException e)
-        {
+        try {
+            return isRepositoryClientData() ? Integer.parseInt(split[REQUEST_ID_INDEX]) : -1;
+        } catch (NumberFormatException e) {
             return -1;
         }
     }
 
-    public String getRenditionName()
-    {
-        return isRepositoryClientData() ? split[2] : "";
+    public String getRenditionName() {
+        return isRepositoryClientData() ? split[RENDITION_INDEX] : "";
     }
 
-    public void appendDebug(String message)
-    {
+    public void appendDebug(String message) {
         if (isDebugRequested())
         {
-            split[9] += DEBUG_SEPARATOR+ message;
+            split[DEBUG_INDEX] += DEBUG_SEPARATOR + message;
         }
     }
 
-    public boolean isDebugRequested()
-    {
+    public boolean isDebugRequested() {
         return isRepositoryClientData() && split[9].startsWith(DEBUG);
     }
 
-    @Override
-    public String toString()
-    {
-        if (split == null)
-        {
+    @Override public String toString() {
+        if (split == null) {
             return origClientData;
         }
         StringJoiner sj = new StringJoiner(CLIENT_DATA_SEPARATOR);
-        Stream.of(split).forEach(element -> sj.add(element));
+        Stream.of(split).forEach(sj::add);
         return sj.toString();
     }
+
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    public static class Builder
+    {
+        private final RepositoryClientData clientData = new RepositoryClientData(emptyClientData());
+
+        private Builder()
+        {
+        }
+
+        private static String emptyClientData()
+        {
+            StringJoiner sj = new StringJoiner(CLIENT_DATA_SEPARATOR, REPO_ID+"ACS1234"+CLIENT_DATA_SEPARATOR, "");
+            for (int i=1; i<EXPECTED_ELEMENTS; i++)
+            {
+                sj.add(Integer.toString(i));
+            }
+            return sj.toString();
+        }
+
+        public Builder withRepoId(final String version)
+        {
+            clientData.split[REPO_INDEX] = REPO_ID+version;
+            return this;
+        }
+
+        public Builder withRequestId(final int requestId)
+        {
+            clientData.split[REQUEST_ID_INDEX] = Integer.toString(requestId);
+            return this;
+        }
+
+        public Builder withRenditionName(final String renditionName)
+        {
+            clientData.split[RENDITION_INDEX] = renditionName;
+            return this;
+        }
+
+        public Builder withDebug()
+        {
+            clientData.split[DEBUG_INDEX]=DEBUG;
+            return this;
+        }
+
+        public Builder withDebugMessage(final String message)
+        {
+            clientData.split[DEBUG_INDEX]=DEBUG+DEBUG_SEPARATOR+message;
+            return this;
+        }
+
+        public RepositoryClientData build()
+        {
+            return clientData;
+        }
+    }
 }
diff --git a/model/src/test/java/org/alfresco/transform/common/RepositoryClientDataTest.java b/model/src/test/java/org/alfresco/transform/common/RepositoryClientDataTest.java
index 28350925..56fcc773 100644
--- a/model/src/test/java/org/alfresco/transform/common/RepositoryClientDataTest.java
+++ b/model/src/test/java/org/alfresco/transform/common/RepositoryClientDataTest.java
@@ -40,19 +40,13 @@ public class RepositoryClientDataTest
     @Test
     void AcsClientDataWithDebugTest()
     {
-        String clientData = new StringJoiner(CLIENT_DATA_SEPARATOR)
-            .add(REPO_ID + "ACS1234")
-            .add("1")
-            .add("renditionName")
-            .add("3")
-            .add("4")
-            .add("5")
-            .add("54321")
-            .add("7")
-            .add("8")
-            .add(DEBUG)
-            .toString();
-        repositoryClientData = new RepositoryClientData(clientData);
+        repositoryClientData = RepositoryClientData.builder()
+                                   .withRepoId("ACS1234")
+                                   .withRenditionName("renditionName")
+                                   .withRequestId(54321)
+                                   .withDebug()
+                                   .build();
+        String clientData = repositoryClientData.toString();
 
         assertEquals("ACS1234", repositoryClientData.getAcsVersion());
         assertEquals("renditionName", repositoryClientData.getRenditionName());
diff --git a/model/src/test/java/org/alfresco/transform/common/TransformerDebugTest.java b/model/src/test/java/org/alfresco/transform/common/TransformerDebugTest.java
index 48f15056..4f34fd55 100644
--- a/model/src/test/java/org/alfresco/transform/common/TransformerDebugTest.java
+++ b/model/src/test/java/org/alfresco/transform/common/TransformerDebugTest.java
@@ -39,11 +39,8 @@ import java.util.StringJoiner;
 
 import static org.alfresco.transform.common.Mimetype.MIMETYPE_TEXT_PLAIN;
 import static org.alfresco.transform.common.Mimetype.MIMETYPE_WORD;
-import static org.alfresco.transform.common.RepositoryClientData.CLIENT_DATA_SEPARATOR;
-import static org.alfresco.transform.common.RepositoryClientData.DEBUG;
 import static org.alfresco.transform.common.RepositoryClientData.DEBUG_SEPARATOR;
-import static org.alfresco.transform.common.RepositoryClientData.REPO_ID;
-import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
 
 /**
  * Tests TransformerDebug. AbstractRouterTest in the t-router contains more complete end to end tests. The tests in this
@@ -72,7 +69,7 @@ class TransformerDebugTest
         TransformRequest request = TransformRequest.builder()
                 .withSourceSize(sourceSize)
                 .withInternalContext(InternalContext.initialise(null))
-                .withClientData(clientDataWithDebugRequest(renditionName))
+                .withClientData(RepositoryClientData.builder().withRenditionName(renditionName).build().toString())
                 .build();
         TransformStack.setInitialSourceReference(request.getInternalContext(), "fileRef");
 
@@ -108,22 +105,6 @@ class TransformerDebugTest
         }
     }
 
-    private String clientDataWithDebugRequest(String renditionName)
-    {
-        return new StringJoiner(CLIENT_DATA_SEPARATOR)
-            .add(REPO_ID + "ACS1234")
-            .add("1")
-            .add(renditionName)
-            .add("3")
-            .add("4")
-            .add("5")
-            .add("54321")
-            .add("7")
-            .add("8")
-            .add(DEBUG)
-            .toString();
-    }
-
     private void monitorLogs(Level logLevel)
     {
         Logger logger = (Logger)LoggerFactory.getLogger(TransformerDebug.class);
@@ -289,7 +270,7 @@ class TransformerDebugTest
     {
         monitorLogs(Level.TRACE);
 
-        String origClientData = clientDataWithDebugRequest("");
+        String origClientData = RepositoryClientData.builder().build().toString();
         TransformReply reply = TransformReply.builder()
                 .withInternalContext(InternalContext.initialise(null))
                 .withErrorDetails("T-Request was null - a major error")
@@ -309,7 +290,7 @@ class TransformerDebugTest
     {
         monitorLogs(Level.TRACE);
 
-        String origClientData = clientDataWithDebugRequest("");
+        String origClientData = RepositoryClientData.builder().withDebug().build().toString();
         TransformReply reply = TransformReply.builder()
                 .withInternalContext(InternalContext.initialise(null))
                 .withErrorDetails("T-Request was null - a major error")