diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/ErrorDto.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/ErrorDto.java
index 8e97eabf8e..3ebcdc6e8e 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/ErrorDto.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/ErrorDto.java
@@ -2,6 +2,7 @@ package sonia.scm.api.v2.resources;
 
 import com.fasterxml.jackson.annotation.JsonInclude;
 import lombok.Getter;
+import org.slf4j.MDC;
 import sonia.scm.ContextEntry;
 import sonia.scm.NotFoundException;
 
@@ -29,6 +30,6 @@ public class ErrorDto {
   }
 
   static ErrorDto from(NotFoundException notFoundException) {
-    return new ErrorDto("todo", "todo", notFoundException.getContext(), notFoundException.getMessage());
+    return new ErrorDto(MDC.get("transaction_id"), "todo", notFoundException.getContext(), notFoundException.getMessage());
   }
 }
diff --git a/scm-webapp/src/main/java/sonia/scm/filter/MDCFilter.java b/scm-webapp/src/main/java/sonia/scm/filter/MDCFilter.java
index ffc976198c..b77a927a2d 100644
--- a/scm-webapp/src/main/java/sonia/scm/filter/MDCFilter.java
+++ b/scm-webapp/src/main/java/sonia/scm/filter/MDCFilter.java
@@ -41,6 +41,8 @@ import org.apache.shiro.subject.Subject;
 import org.slf4j.MDC;
 
 import sonia.scm.SCMContext;
+import sonia.scm.security.DefaultKeyGenerator;
+import sonia.scm.security.KeyGenerator;
 import sonia.scm.web.filter.HttpFilter;
 
 //~--- JDK imports ------------------------------------------------------------
@@ -61,27 +63,26 @@ import sonia.scm.Priority;
 @WebElement(Filters.PATTERN_ALL)
 public class MDCFilter extends HttpFilter
 {
+  private static final DefaultKeyGenerator TRANSACTION_KEY_GENERATOR = new DefaultKeyGenerator();
 
-  /** Field description */
   @VisibleForTesting
   static final String MDC_CLIENT_HOST = "client_host";
 
-  /** Field description */
   @VisibleForTesting
   static final String MDC_CLIENT_IP = "client_ip";
-  
-  /** url of the current request */
+
   @VisibleForTesting
   static final String MDC_REQUEST_URI = "request_uri";
-  
-  /** request method */
+
   @VisibleForTesting
   static final String MDC_REQUEST_METHOD = "request_method";
 
-  /** Field description */
   @VisibleForTesting
   static final String MDC_USERNAME = "username";
 
+  @VisibleForTesting
+  static final String MDC_TRANSACTION_ID = "transaction_id";
+
   //~--- methods --------------------------------------------------------------
 
   /**
@@ -105,6 +106,7 @@ public class MDCFilter extends HttpFilter
     MDC.put(MDC_CLIENT_HOST, request.getRemoteHost());
     MDC.put(MDC_REQUEST_METHOD, request.getMethod());
     MDC.put(MDC_REQUEST_URI, request.getRequestURI());
+    MDC.put(MDC_TRANSACTION_ID, TRANSACTION_KEY_GENERATOR.createKey());
 
     try
     {
@@ -117,6 +119,7 @@ public class MDCFilter extends HttpFilter
       MDC.remove(MDC_CLIENT_HOST);
       MDC.remove(MDC_REQUEST_METHOD);
       MDC.remove(MDC_REQUEST_URI);
+      MDC.remove(MDC_TRANSACTION_ID);
     }
   }
 
diff --git a/scm-webapp/src/main/resources/logback.default.xml b/scm-webapp/src/main/resources/logback.default.xml
index 33e914d04d..d03c5a5012 100644
--- a/scm-webapp/src/main/resources/logback.default.xml
+++ b/scm-webapp/src/main/resources/logback.default.xml
@@ -46,7 +46,7 @@
     <!-- encoders are  by default assigned the type
          ch.qos.logback.classic.encoder.PatternLayoutEncoder -->
     <encoder>
-      <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger - %msg%n</pattern>
+      <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] [%-10X{transaction_id}] %-5level %logger - %msg%n</pattern>
     </encoder>
   </appender>
   
diff --git a/scm-webapp/src/main/resources/logback.release.xml b/scm-webapp/src/main/resources/logback.release.xml
index 4cf5906581..03ac987992 100644
--- a/scm-webapp/src/main/resources/logback.release.xml
+++ b/scm-webapp/src/main/resources/logback.release.xml
@@ -61,14 +61,14 @@
 
     <append>true</append>
     <encoder>
-      <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger - %msg%n</pattern>
+      <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] [%-10X{transaction_id}] %-5level %logger - %msg%n</pattern>
     </encoder>
   </appender>
 
   <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
 
     <encoder>
-      <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger - %msg%n</pattern>
+      <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] [%-10X{transaction_id}] %-5level %logger - %msg%n</pattern>
     </encoder>
     
   </appender>
diff --git a/scm-webapp/src/test/java/sonia/scm/filter/MDCFilterTest.java b/scm-webapp/src/test/java/sonia/scm/filter/MDCFilterTest.java
index 56e1a74572..efd3dbbbc0 100644
--- a/scm-webapp/src/test/java/sonia/scm/filter/MDCFilterTest.java
+++ b/scm-webapp/src/test/java/sonia/scm/filter/MDCFilterTest.java
@@ -101,6 +101,7 @@ public class MDCFilterTest extends AbstractTestBase {
     assertEquals("127.0.0.1", chain.ctx.get(MDCFilter.MDC_CLIENT_IP));
     assertEquals("localhost", chain.ctx.get(MDCFilter.MDC_CLIENT_HOST));
     assertEquals("GET", chain.ctx.get(MDCFilter.MDC_REQUEST_METHOD));
+    assertNotNull(chain.ctx.get(MDCFilter.MDC_TRANSACTION_ID));
   }
   
   /**