diff --git a/src/main/java/net/sourceforge/plantuml/servlet/DiagramResponse.java b/src/main/java/net/sourceforge/plantuml/servlet/DiagramResponse.java
index e290ec2..cae74c8 100644
--- a/src/main/java/net/sourceforge/plantuml/servlet/DiagramResponse.java
+++ b/src/main/java/net/sourceforge/plantuml/servlet/DiagramResponse.java
@@ -76,7 +76,7 @@ class DiagramResponse {
         request = rq;
     }
 
-    void sendDiagram(String uml, int idx) throws IOException {
+    void sendDiagram(String uml, int idx, boolean badRequestOnError) throws IOException {
         response.addHeader("Access-Control-Allow-Origin", "*");
         response.setContentType(getContentType());
         SourceStringReader reader = new SourceStringReader(uml);
@@ -99,6 +99,9 @@ class DiagramResponse {
             addHeaderForCache(blockUml);
         }
         final Diagram diagram = blockUml.getDiagram();
+        if (diagram instanceof PSystemError) {
+            response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
+        }
         final ImageData result = diagram.exportDiagram(response.getOutputStream(), idx, new FileFormatOption(format));
     }
 
diff --git a/src/main/java/net/sourceforge/plantuml/servlet/ProxyServlet.java b/src/main/java/net/sourceforge/plantuml/servlet/ProxyServlet.java
index c124122..f99d8e2 100644
--- a/src/main/java/net/sourceforge/plantuml/servlet/ProxyServlet.java
+++ b/src/main/java/net/sourceforge/plantuml/servlet/ProxyServlet.java
@@ -85,7 +85,7 @@ public class ProxyServlet extends HttpServlet {
         // generate the response
         DiagramResponse dr = new DiagramResponse(response, getOutputFormat(fmt), request);
         try {
-            dr.sendDiagram(uml, 0);
+            dr.sendDiagram(uml, 0, false);
         } catch (IIOException iioe) {
             // Browser has closed the connection, so the HTTP OutputStream is closed
             // Silently catch the exception to avoid annoying log
diff --git a/src/main/java/net/sourceforge/plantuml/servlet/UmlDiagramService.java b/src/main/java/net/sourceforge/plantuml/servlet/UmlDiagramService.java
index 2481201..21a76d4 100644
--- a/src/main/java/net/sourceforge/plantuml/servlet/UmlDiagramService.java
+++ b/src/main/java/net/sourceforge/plantuml/servlet/UmlDiagramService.java
@@ -23,17 +23,18 @@
  */
 package net.sourceforge.plantuml.servlet;
 
-import java.io.IOException;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
+import net.sourceforge.plantuml.FileFormat;
+import net.sourceforge.plantuml.servlet.utility.UmlExtractor;
+
 import javax.imageio.IIOException;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
-
-import net.sourceforge.plantuml.FileFormat;
-import net.sourceforge.plantuml.servlet.utility.UmlExtractor;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /**
  * Common service servlet to produce diagram from compressed UML source contained in the end part of the requested URI.
@@ -59,7 +60,36 @@ public abstract class UmlDiagramService extends HttpServlet {
         DiagramResponse dr = new DiagramResponse(response, getOutputFormat(), request);
         final int idx = Integer.parseInt(sourceAndIdx[1]);
         try {
-            dr.sendDiagram(uml, idx);
+            dr.sendDiagram(uml, idx, false);
+        } catch (IIOException iioe) {
+            // Browser has closed the connection, so the HTTP OutputStream is closed
+            // Silently catch the exception to avoid annoying log
+        }
+        dr = null;
+    }
+
+    @Override
+    public void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {
+
+        // build the UML source from the compressed request parameter
+        final String[] sourceAndIdx = getSourceAndIdx(request);
+//        final String uml;
+
+        final StringBuilder uml = new StringBuilder();
+        final BufferedReader in = request.getReader();
+        while (true) {
+            final String line = in.readLine();
+            if (line == null) {
+                break;
+            }
+            uml.append(line).append('\n');
+        }
+
+        // generate the response
+        DiagramResponse dr = new DiagramResponse(response, getOutputFormat(), request);
+        final int idx = Integer.parseInt(sourceAndIdx[1]);
+        try {
+            dr.sendDiagram(uml.toString(), idx, true);
         } catch (IIOException iioe) {
             // Browser has closed the connection, so the HTTP OutputStream is closed
             // Silently catch the exception to avoid annoying log
diff --git a/src/test/java/net/sourceforge/plantuml/servlet/TestSVG.java b/src/test/java/net/sourceforge/plantuml/servlet/TestSVG.java
index 526baab..4928df6 100644
--- a/src/test/java/net/sourceforge/plantuml/servlet/TestSVG.java
+++ b/src/test/java/net/sourceforge/plantuml/servlet/TestSVG.java
@@ -1,10 +1,13 @@
 package net.sourceforge.plantuml.servlet;
 
 import com.meterware.httpunit.GetMethodWebRequest;
+import com.meterware.httpunit.PostMethodWebRequest;
 import com.meterware.httpunit.WebConversation;
 import com.meterware.httpunit.WebRequest;
 import com.meterware.httpunit.WebResponse;
 
+import java.io.ByteArrayInputStream;
+import java.nio.charset.Charset;
 import java.util.Scanner;
 
 public class TestSVG extends WebappTestCase {
@@ -25,6 +28,47 @@ public class TestSVG extends WebappTestCase {
         assertTrue(diagramLen < 3000);
     }
 
+    /**
+     * Verifies the generation of the SVG for the Bob -> Alice sample
+     */
+    public void testPostedSequenceDiagram() throws Exception {
+        WebConversation conversation = new WebConversation();
+        PostMethodWebRequest request = new PostMethodWebRequest(
+                getServerUrl() + "svg/",
+                new ByteArrayInputStream("@startuml\nBob -> Alice\n@enduml".getBytes(Charset.defaultCharset())),
+                "text/plain");
+
+        WebResponse response = conversation.getResource(request);
+
+        assertEquals(200, response.getResponseCode());
+
+        // Analyze response
+        // Verifies the Content-Type header
+        assertEquals("Response content type is not SVG", "image/svg+xml", response.getContentType());
+        // Get the content and verify its size
+
+        String diagram = response.getText();
+
+        int diagramLen = diagram.length();
+        assertTrue(diagramLen > 1000);
+        assertTrue(diagramLen < 3000);
+    }
+
+    /**
+     * Verifies the generation of the SVG for the Bob -> Alice sample
+     */
+    public void testPostedInvalidSequenceDiagram() throws Exception {
+        WebConversation conversation = new WebConversation();
+        PostMethodWebRequest request = new PostMethodWebRequest(
+                getServerUrl() + "svg/",
+                new ByteArrayInputStream("@startuml\n[Bob\n@enduml".getBytes(Charset.defaultCharset())),
+                "text/plain");
+
+        WebResponse response = conversation.getResource(request);
+
+        assertEquals(400, response.getResponseCode());
+    }
+
     /**
      * Check the content of the SVG
      */