diff --git a/gitiles-servlet/src/main/java/com/google/gitiles/BaseServlet.java b/gitiles-servlet/src/main/java/com/google/gitiles/BaseServlet.java
index 874e593..387a15f 100644
--- a/gitiles-servlet/src/main/java/com/google/gitiles/BaseServlet.java
+++ b/gitiles-servlet/src/main/java/com/google/gitiles/BaseServlet.java
@@ -280,7 +280,7 @@
     if (!allData.containsKey("repositoryName") && view.getRepositoryName() != null) {
       allData.put("repositoryName", view.getRepositoryName());
     }
-    if (!allData.containsKey("breadcrumbs")) {
+    if (!allData.containsKey("breadcrumbs") && view.getRepositoryName() != null) {
       allData.put("breadcrumbs", view.getBreadcrumbs());
     }
 
diff --git a/gitiles-servlet/src/main/java/com/google/gitiles/doc/DocServlet.java b/gitiles-servlet/src/main/java/com/google/gitiles/doc/DocServlet.java
index 3c7f54a..bd5c481 100644
--- a/gitiles-servlet/src/main/java/com/google/gitiles/doc/DocServlet.java
+++ b/gitiles-servlet/src/main/java/com/google/gitiles/doc/DocServlet.java
@@ -14,7 +14,6 @@
 
 package com.google.gitiles.doc;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
 import static javax.servlet.http.HttpServletResponse.SC_INTERNAL_SERVER_ERROR;
 import static javax.servlet.http.HttpServletResponse.SC_NOT_FOUND;
 import static javax.servlet.http.HttpServletResponse.SC_NOT_MODIFIED;
@@ -25,16 +24,19 @@
 
 import com.google.common.base.MoreObjects;
 import com.google.common.base.Strings;
+import com.google.common.base.Throwables;
 import com.google.common.hash.Hasher;
 import com.google.common.hash.Hashing;
 import com.google.common.net.HttpHeaders;
 import com.google.gitiles.BaseServlet;
-import com.google.gitiles.FormatType;
 import com.google.gitiles.GitilesAccess;
 import com.google.gitiles.GitilesView;
 import com.google.gitiles.Renderer;
 import com.google.gitiles.ViewFilter;
+import com.google.gitiles.doc.html.StreamHtmlBuilder;
 import java.io.IOException;
+import java.io.OutputStream;
+import java.io.Writer;
 import java.util.HashMap;
 import java.util.Map;
 import javax.annotation.Nullable;
@@ -165,14 +167,9 @@
       MarkdownFile srcFile)
       throws IOException {
     Map<String, Object> data = new HashMap<>();
-    Navbar navbar = new Navbar();
-    if (navFile != null) {
-      navbar.setFormatter(fmt.setFilePath(navFile.path).build());
-      navbar.setMarkdown(navFile.content);
-    }
-    data.putAll(navbar.toSoyData());
+    data.putAll(buildNavbar(fmt, navFile));
 
-    Node doc = GitilesMarkdown.parse(srcFile.content);
+    Node doc = GitilesMarkdown.parse(srcFile.consumeContent());
     data.put("pageTitle", pageTitle(doc, srcFile));
     if (view.getType() != GitilesView.Type.ROOTED_DOC) {
       data.put("sourceUrl", GitilesView.show().copyFrom(view).toUrl());
@@ -182,21 +179,24 @@
     if (cfg.analyticsId != null) {
       data.put("analyticsId", cfg.analyticsId);
     }
-    data.put("bodyHtml", fmt.setFilePath(srcFile.path).build().toSoyHtml(doc));
 
-    String page = renderer.render(SOY_TEMPLATE, data);
-    byte[] raw = page.getBytes(UTF_8);
-    res.setContentType(FormatType.HTML.getMimeType());
-    res.setCharacterEncoding(UTF_8.name());
-    setCacheHeaders(req, res);
-    if (acceptsGzipEncoding(req)) {
-      res.addHeader(HttpHeaders.VARY, HttpHeaders.ACCEPT_ENCODING);
-      res.setHeader(HttpHeaders.CONTENT_ENCODING, "gzip");
-      raw = gzip(raw);
+    try (OutputStream out = startRenderCompressedStreamingHtml(req, res, SOY_TEMPLATE, data)) {
+      Writer w = newWriter(out, res);
+      fmt.setFilePath(srcFile.path).build().renderToHtml(new StreamHtmlBuilder(w), doc);
+      w.flush();
+    } catch (RuntimeIOException e) {
+      Throwables.throwIfInstanceOf(e.getCause(), IOException.class);
+      throw e;
     }
-    res.setContentLength(raw.length);
-    res.setStatus(HttpServletResponse.SC_OK);
-    res.getOutputStream().write(raw);
+  }
+
+  private Map<String, Object> buildNavbar(MarkdownToHtml.Builder fmt, MarkdownFile navFile) {
+    Navbar navbar = new Navbar();
+    if (navFile != null) {
+      navbar.setFormatter(fmt.setFilePath(navFile.path).build());
+      navbar.setMarkdown(navFile.consumeContent());
+    }
+    return navbar.toSoyData();
   }
 
   private static String pageTitle(Node doc, MarkdownFile srcFile) {
@@ -282,5 +282,11 @@
     void read(ObjectReader reader, MarkdownConfig cfg) throws IOException {
       content = reader.open(id, OBJ_BLOB).getCachedBytes(cfg.inputLimit);
     }
+
+    byte[] consumeContent() {
+      byte[] c = content;
+      content = null;
+      return c;
+    }
   }
 }
diff --git a/gitiles-servlet/src/main/java/com/google/gitiles/doc/MarkdownToHtml.java b/gitiles-servlet/src/main/java/com/google/gitiles/doc/MarkdownToHtml.java
index 99f1c53..56199b9 100644
--- a/gitiles-servlet/src/main/java/com/google/gitiles/doc/MarkdownToHtml.java
+++ b/gitiles-servlet/src/main/java/com/google/gitiles/doc/MarkdownToHtml.java
@@ -21,6 +21,7 @@
 import com.google.gitiles.GitilesView;
 import com.google.gitiles.ThreadSafePrettifyParser;
 import com.google.gitiles.doc.html.HtmlBuilder;
+import com.google.gitiles.doc.html.SoyHtmlBuilder;
 import com.google.template.soy.data.SanitizedContent;
 import com.google.template.soy.shared.restricted.EscapingConventions.FilterImageDataUri;
 import com.google.template.soy.shared.restricted.EscapingConventions.FilterNormalizeUri;
@@ -118,8 +119,8 @@
     }
   }
 
-  private final HtmlBuilder html = new HtmlBuilder();
-  private final TocFormatter toc = new TocFormatter(html, 3);
+  private HtmlBuilder html;
+  private TocFormatter toc;
   private final String requestUri;
   private final GitilesView view;
   private final MarkdownConfig config;
@@ -143,14 +144,26 @@
   }
 
   /** Render the document AST to sanitized HTML. */
-  public SanitizedContent toSoyHtml(Node node) {
-    if (node == null) {
-      return null;
+  public void renderToHtml(HtmlBuilder out, Node node) {
+    if (node != null) {
+      html = out;
+      toc = new TocFormatter(html, 3);
+      toc.setRoot(node);
+      node.accept(this);
+      html.finish();
+      html = null;
+      toc = null;
     }
+  }
 
-    toc.setRoot(node);
-    node.accept(this);
-    return html.toSoy();
+  /** Render the document AST to sanitized HTML. */
+  public SanitizedContent toSoyHtml(Node node) {
+    if (node != null) {
+      SoyHtmlBuilder out = new SoyHtmlBuilder();
+      renderToHtml(out, node);
+      return out.toSoy();
+    }
+    return null;
   }
 
   @Override
diff --git a/gitiles-servlet/src/main/java/com/google/gitiles/doc/RuntimeIOException.java b/gitiles-servlet/src/main/java/com/google/gitiles/doc/RuntimeIOException.java
new file mode 100644
index 0000000..8ef7923
--- /dev/null
+++ b/gitiles-servlet/src/main/java/com/google/gitiles/doc/RuntimeIOException.java
@@ -0,0 +1,26 @@
+// Copyright (C) 2017 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.doc;
+
+import java.io.IOException;
+
+/** {@link IOException} wrapped inside RuntimeException. */
+public class RuntimeIOException extends RuntimeException {
+  private static final long serialVersionUID = 1L;
+
+  public RuntimeIOException(IOException cause) {
+    super(cause);
+  }
+}
diff --git a/gitiles-servlet/src/main/java/com/google/gitiles/doc/html/HtmlBuilder.java b/gitiles-servlet/src/main/java/com/google/gitiles/doc/html/HtmlBuilder.java
index 9551e94..b8f43b0 100644
--- a/gitiles-servlet/src/main/java/com/google/gitiles/doc/html/HtmlBuilder.java
+++ b/gitiles-servlet/src/main/java/com/google/gitiles/doc/html/HtmlBuilder.java
@@ -19,9 +19,7 @@
 
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableSet;
-import com.google.template.soy.data.SanitizedContent;
-import com.google.template.soy.data.SanitizedContent.ContentKind;
-import com.google.template.soy.data.UnsafeSanitizedContentOrdainer;
+import com.google.gitiles.doc.RuntimeIOException;
 import com.google.template.soy.shared.restricted.EscapingConventions.EscapeHtml;
 import com.google.template.soy.shared.restricted.EscapingConventions.FilterImageDataUri;
 import com.google.template.soy.shared.restricted.EscapingConventions.FilterNormalizeUri;
@@ -37,8 +35,10 @@
  * <p>Useful but critical attributes like {@code href} on anchors or {@code src} on img permit only
  * safe subset of URIs, primarily {@code http://}, {@code https://}, and for image src {@code
  * data:image/*;base64,...}.
+ *
+ * <p>See concrete subclasses {@link SoyHtmlBuilder} and {@link StreamHtmlBuilder}.
  */
-public final class HtmlBuilder {
+public abstract class HtmlBuilder {
   private static final ImmutableSet<String> ALLOWED_TAGS =
       ImmutableSet.of(
           "h1",
@@ -112,12 +112,12 @@
     return GIT_URI.matcher(val).find();
   }
 
-  private final StringBuilder htmlBuf;
+  private final Appendable htmlBuf;
   private final Appendable textBuf;
   private String tag;
 
-  public HtmlBuilder() {
-    htmlBuf = new StringBuilder();
+  HtmlBuilder(Appendable out) {
+    htmlBuf = out;
     textBuf = EscapeHtml.INSTANCE.escape(htmlBuf);
   }
 
@@ -125,7 +125,11 @@
   public HtmlBuilder open(String tagName) {
     checkArgument(ALLOWED_TAGS.contains(tagName), "invalid HTML tag %s", tagName);
     finishActiveTag();
-    htmlBuf.append('<').append(tagName);
+    try {
+      htmlBuf.append('<').append(tagName);
+    } catch (IOException e) {
+      throw new RuntimeIOException(e);
+    }
     tag = tagName;
     return this;
   }
@@ -167,7 +171,7 @@
       htmlBuf.append('"');
       return this;
     } catch (IOException e) {
-      throw new IllegalStateException(e);
+      throw new RuntimeIOException(e);
     }
   }
 
@@ -190,10 +194,14 @@
 
   private void finishActiveTag() {
     if (tag != null) {
-      if (SELF_CLOSING_TAGS.contains(tag)) {
-        htmlBuf.append(" />");
-      } else {
-        htmlBuf.append('>');
+      try {
+        if (SELF_CLOSING_TAGS.contains(tag)) {
+          htmlBuf.append(" />");
+        } else {
+          htmlBuf.append('>');
+        }
+      } catch (IOException e) {
+        throw new RuntimeIOException(e);
       }
       tag = null;
     }
@@ -205,7 +213,11 @@
         ALLOWED_TAGS.contains(tag) && !SELF_CLOSING_TAGS.contains(tag), "invalid HTML tag %s", tag);
 
     finishActiveTag();
-    htmlBuf.append("</").append(tag).append('>');
+    try {
+      htmlBuf.append("</").append(tag).append('>');
+    } catch (IOException e) {
+      throw new RuntimeIOException(e);
+    }
     return this;
   }
 
@@ -216,14 +228,18 @@
       textBuf.append(in);
       return this;
     } catch (IOException e) {
-      throw new IllegalStateException(e);
+      throw new RuntimeIOException(e);
     }
   }
 
   /** Append a space outside of an element. */
   public HtmlBuilder space() {
     finishActiveTag();
-    htmlBuf.append(' ');
+    try {
+      htmlBuf.append(' ');
+    } catch (IOException e) {
+      throw new RuntimeIOException(e);
+    }
     return this;
   }
 
@@ -233,12 +249,15 @@
   public void entity(String entity) {
     checkArgument(HTML_ENTITY.matcher(entity).matches(), "invalid entity %s", entity);
     finishActiveTag();
-    htmlBuf.append(entity);
+    try {
+      htmlBuf.append(entity);
+    } catch (IOException e) {
+      throw new RuntimeIOException(e);
+    }
   }
 
-  /** Bless the current content as HTML. */
-  public SanitizedContent toSoy() {
+  /** Finish the document. */
+  public void finish() {
     finishActiveTag();
-    return UnsafeSanitizedContentOrdainer.ordainAsSafe(htmlBuf.toString(), ContentKind.HTML);
   }
 }
diff --git a/gitiles-servlet/src/main/java/com/google/gitiles/doc/html/SoyHtmlBuilder.java b/gitiles-servlet/src/main/java/com/google/gitiles/doc/html/SoyHtmlBuilder.java
new file mode 100644
index 0000000..23e6ee6
--- /dev/null
+++ b/gitiles-servlet/src/main/java/com/google/gitiles/doc/html/SoyHtmlBuilder.java
@@ -0,0 +1,39 @@
+// Copyright (C) 2017 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.doc.html;
+
+import com.google.template.soy.data.SanitizedContent;
+import com.google.template.soy.data.SanitizedContent.ContentKind;
+import com.google.template.soy.data.UnsafeSanitizedContentOrdainer;
+
+/** Builds a document fragment using a restricted subset of HTML. */
+public final class SoyHtmlBuilder extends HtmlBuilder {
+  private final StringBuilder buf;
+
+  public SoyHtmlBuilder() {
+    this(new StringBuilder());
+  }
+
+  private SoyHtmlBuilder(StringBuilder buf) {
+    super(buf);
+    this.buf = buf;
+  }
+
+  /** Bless the current content as HTML. */
+  public SanitizedContent toSoy() {
+    finish();
+    return UnsafeSanitizedContentOrdainer.ordainAsSafe(buf.toString(), ContentKind.HTML);
+  }
+}
diff --git a/gitiles-servlet/src/main/java/com/google/gitiles/doc/html/StreamHtmlBuilder.java b/gitiles-servlet/src/main/java/com/google/gitiles/doc/html/StreamHtmlBuilder.java
new file mode 100644
index 0000000..467dd43
--- /dev/null
+++ b/gitiles-servlet/src/main/java/com/google/gitiles/doc/html/StreamHtmlBuilder.java
@@ -0,0 +1,24 @@
+// Copyright (C) 2017 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.doc.html;
+
+import java.io.Writer;
+
+/** Writes sanitized HTML to a stream. */
+public final class StreamHtmlBuilder extends HtmlBuilder {
+  public StreamHtmlBuilder(Writer out) {
+    super(out);
+  }
+}
diff --git a/gitiles-servlet/src/main/resources/com/google/gitiles/templates/Doc.soy b/gitiles-servlet/src/main/resources/com/google/gitiles/templates/Doc.soy
index 2193c93..e43d2c1 100644
--- a/gitiles-servlet/src/main/resources/com/google/gitiles/templates/Doc.soy
+++ b/gitiles-servlet/src/main/resources/com/google/gitiles/templates/Doc.soy
@@ -25,7 +25,6 @@
  * @param logUrl url for log history of page.
  * @param blameUrl url for blame of page source.
  * @param? navbarHtml markdown ast node to convert.
- * @param bodyHtml safe html to embed into the body of the page.
  */
 {template .markdownDoc}
 <!DOCTYPE html>
@@ -59,7 +58,7 @@
   <div class="Site-content Site-Content--markdown">
     <div class="Container">
       <div class="doc">
-        {$bodyHtml}
+        {call .streamingPlaceholder /}
       </div>
     </div>
   </div>