diff --git a/gitiles-servlet/src/main/java/com/google/gitiles/DiffServlet.java b/gitiles-servlet/src/main/java/com/google/gitiles/DiffServlet.java
index 4e2c4ba..5b091f2 100644
--- a/gitiles-servlet/src/main/java/com/google/gitiles/DiffServlet.java
+++ b/gitiles-servlet/src/main/java/com/google/gitiles/DiffServlet.java
@@ -18,6 +18,7 @@
 import static javax.servlet.http.HttpServletResponse.SC_NOT_FOUND;
 
 import com.google.common.base.Charsets;
+import com.google.common.io.BaseEncoding;
 import com.google.gitiles.CommitData.Field;
 import com.google.gitiles.DateFormatter.Format;
 
@@ -38,6 +39,7 @@
 
 import java.io.IOException;
 import java.io.OutputStream;
+import java.io.OutputStreamWriter;
 import java.util.Arrays;
 import java.util.Map;
 import java.util.Set;
@@ -58,7 +60,7 @@
   }
 
   @Override
-  protected void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException {
+  protected void doGetHtml(HttpServletRequest req, HttpServletResponse res) throws IOException {
     GitilesView view = ViewFilter.getView(req);
     Repository repo = ServletUtils.getRepository(req);
 
@@ -115,7 +117,8 @@
 
       try (OutputStream out = res.getOutputStream()) {
         out.write(html[0].getBytes(Charsets.UTF_8));
-        formatHtmlDiff(out, view, repo, oldTree, newTree, view.getPathPart());
+        DiffFormatter diff = new HtmlDiffFormatter(renderer, view, out);
+        formatDiff(repo, oldTree, newTree, view.getPathPart(), diff);
         out.write(html[1].getBytes(Charsets.UTF_8));
       }
     } finally {
@@ -126,6 +129,33 @@
     }
   }
 
+  @Override
+  protected void doGetText(HttpServletRequest req, HttpServletResponse res)
+      throws IOException {
+    GitilesView view = ViewFilter.getView(req);
+    Repository repo = ServletUtils.getRepository(req);
+
+    RevWalk walk = new RevWalk(repo);
+    try {
+      AbstractTreeIterator oldTree;
+      AbstractTreeIterator newTree;
+      try {
+        oldTree = getTreeIterator(walk, view.getOldRevision().getId());
+        newTree = getTreeIterator(walk, view.getRevision().getId());
+      } catch (MissingObjectException | IncorrectObjectTypeException e) {
+        res.setStatus(SC_NOT_FOUND);
+        return;
+      }
+
+      try (OutputStream out = BaseEncoding.base64()
+          .encodingStream(new OutputStreamWriter(res.getOutputStream()))) {
+        formatDiff(repo, oldTree, newTree, view.getPathPart(), new DiffFormatter(out));
+      }
+    } finally {
+      walk.release();
+    }
+  }
+
   private static TreeWalk newTreeWalk(RevWalk walk, GitilesView view) throws IOException {
     if (view.getPathPart().isEmpty()) {
       return null;
@@ -164,11 +194,8 @@
     return new String[] {html.substring(0, lt), html.substring(gt + 1)};
   }
 
-  private void formatHtmlDiff(OutputStream out, GitilesView view,
-      Repository repo, AbstractTreeIterator oldTree,
-      AbstractTreeIterator newTree, String path)
-      throws IOException {
-    DiffFormatter diff = new HtmlDiffFormatter(renderer, view, out);
+  private static void formatDiff(Repository repo, AbstractTreeIterator oldTree,
+      AbstractTreeIterator newTree, String path, DiffFormatter diff) throws IOException {
     try {
       if (!path.equals("")) {
         diff.setPathFilter(PathFilter.create(path));
diff --git a/gitiles-servlet/src/test/java/com/google/gitiles/DiffServletTest.java b/gitiles-servlet/src/test/java/com/google/gitiles/DiffServletTest.java
new file mode 100644
index 0000000..92a52ce
--- /dev/null
+++ b/gitiles-servlet/src/test/java/com/google/gitiles/DiffServletTest.java
@@ -0,0 +1,126 @@
+// Copyright (C) 2014 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gitiles;
+
+import static com.google.common.collect.Iterables.getOnlyElement;
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.junit.Assert.assertEquals;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.io.BaseEncoding;
+
+import org.eclipse.jgit.diff.DiffEntry;
+import org.eclipse.jgit.diff.DiffEntry.ChangeType;
+import org.eclipse.jgit.diff.DiffEntry.Side;
+import org.eclipse.jgit.diff.Edit;
+import org.eclipse.jgit.diff.Edit.Type;
+import org.eclipse.jgit.diff.RawText;
+import org.eclipse.jgit.internal.storage.dfs.DfsRepository;
+import org.eclipse.jgit.internal.storage.dfs.DfsRepositoryDescription;
+import org.eclipse.jgit.internal.storage.dfs.InMemoryRepository;
+import org.eclipse.jgit.junit.TestRepository;
+import org.eclipse.jgit.patch.FileHeader;
+import org.eclipse.jgit.patch.Patch;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.junit.Before;
+import org.junit.Test;
+
+public class DiffServletTest {
+  private TestRepository<DfsRepository> repo;
+  private GitilesServlet servlet;
+
+  @Before
+  public void setUp() throws Exception {
+    DfsRepository r = new InMemoryRepository(new DfsRepositoryDescription("test"));
+    repo = new TestRepository<DfsRepository>(r);
+    servlet = TestGitilesServlet.create(repo);
+  }
+
+  @Test
+  public void diffFileNoParents() throws Exception {
+    String contents = "foo\ncontents\n";
+    RevCommit c = repo.update("master", repo.commit().add("foo", contents));
+
+    FakeHttpServletRequest req = FakeHttpServletRequest.newRequest();
+    req.setPathInfo("/test/+diff/" + c.name() + "^!/foo");
+    req.setQueryString("format=TEXT");
+    FakeHttpServletResponse res = new FakeHttpServletResponse();
+    servlet.service(req, res);
+
+    Patch p = parsePatch(res.getActualBody());
+    FileHeader f = getOnlyElement(p.getFiles());
+    assertEquals(ChangeType.ADD, f.getChangeType());
+    assertEquals(DiffEntry.DEV_NULL, f.getPath(Side.OLD));
+    assertEquals("foo", f.getPath(Side.NEW));
+
+    RawText rt = new RawText(contents.getBytes(UTF_8));
+    Edit e = getOnlyElement(getOnlyElement(f.getHunks()).toEditList());
+    assertEquals(Type.INSERT, e.getType());
+    assertEquals(contents, rt.getString(e.getBeginB(), e.getEndB(), false));
+  }
+
+  @Test
+  public void diffFileOneParent() throws Exception {
+    String contents1 = "foo\n";
+    String contents2 = "foo\ncontents\n";
+    RevCommit c1 = repo.update("master", repo.commit().add("foo", contents1));
+    RevCommit c2 = repo.update("master", repo.commit().parent(c1).add("foo", contents2));
+
+    FakeHttpServletRequest req = FakeHttpServletRequest.newRequest();
+    req.setPathInfo("/test/+diff/" + c2.name() + "^!/foo");
+    req.setQueryString("format=TEXT");
+    FakeHttpServletResponse res = new FakeHttpServletResponse();
+    servlet.service(req, res);
+
+    Patch p = parsePatch(res.getActualBody());
+    FileHeader f = getOnlyElement(p.getFiles());
+    assertEquals(ChangeType.MODIFY, f.getChangeType());
+    assertEquals("foo", f.getPath(Side.OLD));
+    assertEquals("foo", f.getPath(Side.NEW));
+
+    RawText rt2 = new RawText(contents2.getBytes(UTF_8));
+    Edit e = getOnlyElement(getOnlyElement(f.getHunks()).toEditList());
+    assertEquals(Type.INSERT, e.getType());
+    assertEquals("contents\n", rt2.getString(e.getBeginB(), e.getEndB(), false));
+  }
+
+  @Test
+  public void diffDirectory() throws Exception {
+    String contents = "contents\n";
+    RevCommit c = repo.update("master", repo.commit()
+        .add("dir/foo", contents)
+        .add("dir/bar", contents)
+        .add("baz", contents));
+
+    FakeHttpServletRequest req = FakeHttpServletRequest.newRequest();
+    req.setPathInfo("/test/+diff/" + c.name() + "^!/dir");
+    req.setQueryString("format=TEXT");
+    FakeHttpServletResponse res = new FakeHttpServletResponse();
+    servlet.service(req, res);
+
+    Patch p = parsePatch(res.getActualBody());
+    assertEquals(2, p.getFiles().size());
+    assertEquals("dir/bar", p.getFiles().get(0).getPath(Side.NEW));
+    assertEquals("dir/foo", p.getFiles().get(1).getPath(Side.NEW));
+  }
+
+  private static Patch parsePatch(byte[] enc) {
+    byte[] buf = BaseEncoding.base64().decode(new String(enc, UTF_8));
+    Patch p = new Patch();
+    p.parse(buf, 0, buf.length);
+    assertEquals(ImmutableList.of(), p.getErrors());
+    return p;
+  }
+}