diff --git a/src/vs/base/common/callbackList.ts b/src/vs/base/common/callbackList.ts
index f533607af46..4471fb6d632 100644
--- a/src/vs/base/common/callbackList.ts
+++ b/src/vs/base/common/callbackList.ts
@@ -72,6 +72,13 @@ export default class CallbackList {
 		return !this._callbacks || this._callbacks.length === 0;
 	}
 
+	public entries(): [Function, any][] {
+		if (!this._callbacks) {
+			return [];
+		}
+		return this._callbacks.map((fn, index) => <[Function, any]>[fn, this._contexts[index]]);
+	}
+
 	public dispose(): void {
 		this._callbacks = undefined;
 		this._contexts = undefined;
diff --git a/src/vs/workbench/api/node/extHostDocumentSaveParticipant.ts b/src/vs/workbench/api/node/extHostDocumentSaveParticipant.ts
new file mode 100644
index 00000000000..8a391e3d96d
--- /dev/null
+++ b/src/vs/workbench/api/node/extHostDocumentSaveParticipant.ts
@@ -0,0 +1,68 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import Event from 'vs/base/common/event';
+import CallbackList from 'vs/base/common/callbackList';
+import URI from 'vs/base/common/uri';
+import {sequence} from 'vs/base/common/async';
+import {illegalState} from 'vs/base/common/errors';
+import {TPromise} from 'vs/base/common/winjs.base';
+import {ExtHostDocuments} from 'vs/workbench/api/node/extHostDocuments';
+
+export interface TextDocumentWillSaveEvent {
+	waitUntil(t: Thenable<any>): void;
+}
+
+export class ExtHostDocumentSaveParticipant {
+
+	private _callbacks = new CallbackList();
+	private _documents: ExtHostDocuments;
+
+	constructor(documents: ExtHostDocuments) {
+		this._documents = documents;
+	}
+
+	dispose(): void {
+		this._callbacks.dispose();
+	}
+
+	get onWillSaveTextDocumentEvent(): Event<TextDocumentWillSaveEvent> {
+		return (listener, thisArg, disposables) => {
+			this._callbacks.add(listener, thisArg);
+			const result = { dispose: () => this._callbacks.remove(listener, thisArg) };
+			if (Array.isArray(disposables)) {
+				disposables.push(result);
+			}
+			return result;
+		};
+	}
+
+	$participateInSave(resource: URI): TPromise<any> {
+		const entries = this._callbacks.entries();
+
+		return sequence(entries.map(([fn, thisArg]) => {
+			return () => {
+				const document = this._documents.getDocumentData(resource).document;
+				return this._deliverEventAsync(fn, thisArg, document);
+			};
+		}));
+	}
+
+	private _deliverEventAsync(listener: Function, thisArg: any, document: vscode.TextDocument): TPromise<any> {
+		const promises: TPromise<any>[] = [];
+		const event = {
+			waitUntil(p: Thenable<any>) {
+				promises.push(TPromise.wrap(p));
+			}
+		};
+		try {
+			listener.apply(thisArg, [event]);
+		} finally {
+			event.waitUntil = () => { throw illegalState(); };
+			return TPromise.join(promises).then(() => void 0, err => void 0 /* ignore */);
+		}
+	}
+}
\ No newline at end of file
diff --git a/src/vs/workbench/test/node/api/extHostDocumentSaveParticipant.test.ts b/src/vs/workbench/test/node/api/extHostDocumentSaveParticipant.test.ts
new file mode 100644
index 00000000000..4934f66e034
--- /dev/null
+++ b/src/vs/workbench/test/node/api/extHostDocumentSaveParticipant.test.ts
@@ -0,0 +1,140 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+'use strict';
+
+import * as assert from 'assert';
+import URI from 'vs/base/common/uri';
+import {TPromise} from 'vs/base/common/winjs.base';
+import {ExtHostDocuments} from 'vs/workbench/api/node/extHostDocuments';
+import {ExtHostDocumentSaveParticipant, TextDocumentWillSaveEvent} from 'vs/workbench/api/node/extHostDocumentSaveParticipant';
+import {OneGetThreadService} from './testThreadService';
+import * as EditorCommon from 'vs/editor/common/editorCommon';
+
+suite('ExtHostDocumentSaveParticipant', () => {
+
+	let resource = URI.parse('foo:bar');
+	let documents: ExtHostDocuments;
+
+	setup(() => {
+
+		documents = new ExtHostDocuments(OneGetThreadService(null));
+		documents.$acceptModelAdd({
+			isDirty: false,
+			modeId: 'foo',
+			url: resource,
+			versionId: 1,
+			value: {
+				EOL: '\n',
+				lines: ['foo'],
+				BOM: '',
+				length: -1,
+				options: {
+					tabSize: 4,
+					insertSpaces: true,
+					trimAutoWhitespace: true,
+					defaultEOL: EditorCommon.DefaultEndOfLine.LF
+				}
+			}
+		});
+	});
+
+	test('no listeners, no problem', () => {
+		const participant = new ExtHostDocumentSaveParticipant(documents);
+		return participant.$participateInSave(resource).then(() => assert.ok(true));
+	});
+
+	test('event delivery', () => {
+		const participant = new ExtHostDocumentSaveParticipant(documents);
+
+		let event: TextDocumentWillSaveEvent;
+		let sub = participant.onWillSaveTextDocumentEvent(function (e) {
+			event = e;
+		});
+
+		return participant.$participateInSave(resource).then(() => {
+			sub.dispose();
+
+			assert.ok(event);
+			assert.equal(typeof event.waitUntil, 'function');
+		});
+	});
+
+	test('event delivery in subscribe order', () => {
+		const participant = new ExtHostDocumentSaveParticipant(documents);
+
+		let counter = 0;
+		let sub1 = participant.onWillSaveTextDocumentEvent(function (event) {
+			assert.equal(counter++, 0);
+		});
+
+		let sub2 = participant.onWillSaveTextDocumentEvent(function (event) {
+			assert.equal(counter++, 1);
+		});
+
+		return participant.$participateInSave(resource).then(() => {
+			sub1.dispose();
+			sub2.dispose();
+		});
+	});
+
+	test('event delivery, waitUntil', () => {
+		const participant = new ExtHostDocumentSaveParticipant(documents);
+
+		let sub = participant.onWillSaveTextDocumentEvent(function (event) {
+
+			event.waitUntil(TPromise.timeout(10));
+			event.waitUntil(TPromise.timeout(10));
+			event.waitUntil(TPromise.timeout(10));
+		});
+
+		return participant.$participateInSave(resource).then(() => {
+			sub.dispose();
+		});
+
+	});
+
+	test('event delivery, waitUntil must be called sync', () => {
+		const participant = new ExtHostDocumentSaveParticipant(documents);
+
+		let sub = participant.onWillSaveTextDocumentEvent(function (event) {
+
+			event.waitUntil(new TPromise((resolve, reject) => {
+				setTimeout(() => {
+					try {
+						assert.throws(() => event.waitUntil(TPromise.timeout(10)));
+						resolve(void 0);
+					} catch (e) {
+						reject(e);
+					}
+
+				}, 10);
+			}));
+		});
+
+		return participant.$participateInSave(resource).then(() => {
+			sub.dispose();
+		});
+	});
+
+	test('event delivery, waitUntil failure handling', () => {
+		const participant = new ExtHostDocumentSaveParticipant(documents);
+
+		let sub1 = participant.onWillSaveTextDocumentEvent(function (e) {
+			e.waitUntil(TPromise.wrapError('dddd'));
+		});
+
+		let event: TextDocumentWillSaveEvent;
+		let sub2 = participant.onWillSaveTextDocumentEvent(function (e) {
+			event = e;
+		});
+
+		return participant.$participateInSave(resource).then(() => {
+			assert.ok(event);
+			sub1.dispose();
+			sub2.dispose();
+		});
+	});
+
+});