diff --git a/gulpfile.js b/gulpfile.js
index 14282984d7..5ea79f5fb2 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -210,12 +210,6 @@ gulp.task('build/pubbuild.dart', pubbuild(gulp, gulpPlugins, {
 // ------------
 // formatting
 
-gulp.task('build/format.dart', function() {
-  return util.processToPromise(spawn(DART_SDK.DARTFMT, ['-w', CONFIG.dest.dart], {
-    stdio: logs.dartfmt ? 'inherit' : ['ignore', 'ignore', 'inherit']
-  }));
-});
-
 function doCheckFormat() {
   return gulp.src(['Brocfile*.js', 'modules/**/*.ts', 'tools/**/*.ts', '!**/typings/**/*.d.ts',
                    // skipped  due to https://github.com/angular/clang-format/issues/4
@@ -433,7 +427,6 @@ gulp.task('!test.unit.js/karma-run', function(done) {
 gulp.task('test.unit.dart', function (done) {
   runSequence(
     'build/tree.dart',
-    'build/format.dart',
     '!test.unit.dart/karma-server',
     '!test.unit.dart/karma-run',
     function(error) {
@@ -446,7 +439,6 @@ gulp.task('test.unit.dart', function (done) {
 
       watch('modules/angular2/**', { ignoreInitial: true, log: watchLog }, [
         '!build/tree.dart',
-        'build/format.dart',
         '!test.unit.dart/karma-run'
       ]);
     }
@@ -597,7 +589,6 @@ gulp.task('build/packages.dart', function(done) {
     '!build/pubget.angular2.dart',
     '!build/change_detect.dart',
     'build/pure-packages.dart',
-    'build/format.dart',
     done);
 });
 
@@ -640,7 +631,11 @@ gulp.task('!build.tools', function() {
     tsResult.js.pipe(destDir)
   ]).on('end', function() {
     var AngularBuilder = require('./dist/tools/broccoli/angular_builder').AngularBuilder;
-    angularBuilder = new AngularBuilder('dist');
+    angularBuilder = new AngularBuilder({
+      outputPath: 'dist',
+      dartSDK: DART_SDK,
+      logs: logs
+    });
   });
 
   return mergedStream;
diff --git a/tools/broccoli/angular_builder.d.ts b/tools/broccoli/angular_builder.d.ts
new file mode 100644
index 0000000000..c7476f3c49
--- /dev/null
+++ b/tools/broccoli/angular_builder.d.ts
@@ -0,0 +1,5 @@
+interface AngularBuilderOptions {
+  outputPath: string;
+  dartSDK?: any;
+  logs?: any;
+}
diff --git a/tools/broccoli/angular_builder.ts b/tools/broccoli/angular_builder.ts
index dab5656735..43bbecfc1d 100644
--- a/tools/broccoli/angular_builder.ts
+++ b/tools/broccoli/angular_builder.ts
@@ -7,7 +7,6 @@ var path = require('path');
 var printSlowTrees = require('broccoli-slow-trees');
 var Q = require('q');
 
-
 /**
  * BroccoliBuilder facade for all of our build pipelines.
  */
@@ -16,9 +15,9 @@ export class AngularBuilder {
   private browserDevBuilder: BroccoliBuilder;
   private browserProdBuilder: BroccoliBuilder;
   private dartBuilder: BroccoliBuilder;
+  private outputPath: string;
 
-
-  constructor(private outputPath: string) {}
+  constructor(public options: AngularBuilderOptions) { this.outputPath = options.outputPath; }
 
 
   public rebuildBrowserDevTree(): Promise<BuildResult> {
@@ -75,7 +74,12 @@ export class AngularBuilder {
 
 
   private makeDartBuilder(): BroccoliBuilder {
-    let tree = makeDartTree(path.join(this.outputPath, 'dart'));
+    let options = {
+      outputPath: path.join(this.outputPath, 'dart'),
+      dartSDK: this.options.dartSDK,
+      logs: this.options.logs
+    };
+    let tree = makeDartTree(options);
     return new broccoli.Builder(tree);
   }
 
diff --git a/tools/broccoli/broccoli-dartfmt.ts b/tools/broccoli/broccoli-dartfmt.ts
new file mode 100644
index 0000000000..d290d42dcf
--- /dev/null
+++ b/tools/broccoli/broccoli-dartfmt.ts
@@ -0,0 +1,47 @@
+/// <reference path="../typings/node/node.d.ts" />
+/// <reference path="../typings/fs-extra/fs-extra.d.ts" />
+import fse = require('fs-extra');
+import path = require('path');
+import {wrapDiffingPlugin, DiffingBroccoliPlugin, DiffResult} from './diffing-broccoli-plugin';
+var spawn = require('child_process').spawn;
+
+function processToPromise(process) {
+  return new Promise(function(resolve, reject) {
+    process.on('close', function(code) {
+      if (code) {
+        reject(code);
+      } else {
+        resolve();
+      }
+    });
+  });
+}
+
+class DartFormatter implements DiffingBroccoliPlugin {
+  private DARTFMT: string;
+  private verbose: boolean;
+
+  constructor(public inputPath: string, public cachePath: string, options) {
+    if (!options.dartSDK) throw new Error("Missing Dart SDK");
+    this.DARTFMT = options.dartSDK.DARTFMT;
+    this.verbose = options.logs.dartfmt;
+  }
+
+  rebuild(treeDiff: DiffResult): Promise<any> {
+    let args = ['-w'];
+    treeDiff.changedPaths.forEach((changedFile) => {
+      let sourcePath = path.join(this.inputPath, changedFile);
+      let destPath = path.join(this.cachePath, changedFile);
+      if (/\.dart$/.test(changedFile)) args.push(destPath);
+      fse.copySync(sourcePath, destPath);
+    });
+    treeDiff.removedPaths.forEach((removedFile) => {
+      let destPath = path.join(this.cachePath, removedFile);
+      fse.removeSync(destPath);
+    });
+    return processToPromise(spawn(
+        this.DARTFMT, args, {stdio: this.verbose ? 'inherit' : ['ignore', 'ignore', 'inherit']}));
+  }
+}
+
+export default wrapDiffingPlugin(DartFormatter);
diff --git a/tools/broccoli/trees/dart_tree.ts b/tools/broccoli/trees/dart_tree.ts
index d95f16d030..b6848e8afc 100644
--- a/tools/broccoli/trees/dart_tree.ts
+++ b/tools/broccoli/trees/dart_tree.ts
@@ -1,4 +1,5 @@
 /// <reference path="../../typings/node/node.d.ts" />
+/// <reference path="../angular_builder.d.ts" />
 'use strict';
 
 import {MultiCopy} from './../multi_copy';
@@ -11,6 +12,7 @@ var renderLodashTemplate = require('broccoli-lodash');
 var replace = require('broccoli-replace');
 var stew = require('broccoli-stew');
 import ts2dart from '../broccoli-ts2dart';
+import dartfmt from '../broccoli-dartfmt';
 
 /**
  * A funnel starting at modules, including the given filters, and moving into the root.
@@ -138,11 +140,12 @@ function getDocsTree() {
   return mergeTrees([licenses, mdTree, docs]);
 }
 
-module.exports = function makeDartTree(destinationPath) {
-  var sourceTree = mergeTrees([getSourceTree(), getHtmlSourcesTree()]);
+module.exports = function makeDartTree(options: AngularBuilderOptions) {
+  var dartSources = dartfmt(getSourceTree(), {dartSDK: options.dartSDK, logs: options.logs});
+  var sourceTree = mergeTrees([dartSources, getHtmlSourcesTree()]);
   sourceTree = fixDartFolderLayout(sourceTree);
 
   var dartTree = mergeTrees([sourceTree, getTemplatedPubspecsTree(), getDocsTree()]);
 
-  return destCopy(dartTree, destinationPath);
+  return destCopy(dartTree, options.outputPath);
 };