diff --git a/messenger/messenger-tests.ts b/messenger/messenger-tests.ts
new file mode 100644
index 000000000..1f560e6e2
--- /dev/null
+++ b/messenger/messenger-tests.ts
@@ -0,0 +1,14 @@
+/// <reference path="messenger.d.ts"/>
+
+var message = Messenger().post({
+    message: "message",
+    hideAfter: 5,
+    showCloseButton: true,
+    type: "error"
+});
+message.update({
+    type: "error",
+    message: "Error calculating position"
+});
+
+Messenger().hideAll();
diff --git a/messenger/messenger.d.ts b/messenger/messenger.d.ts
new file mode 100644
index 000000000..3aacf2f88
--- /dev/null
+++ b/messenger/messenger.d.ts
@@ -0,0 +1,119 @@
+// Type definitions for Messenger.js 1.4.0
+// Project: https://github.com/HubSpot/messenger
+// Definitions by: Derek Cicerone <https://github.com/derekcicerone>
+// Definitions: https://github.com/borisyankov/DefinitelyTyped
+
+interface IMessenger {
+    (): Messenger;
+    options: MessengerOptions;
+}
+
+interface Messenger {
+    /**
+     * Posts a message.
+     */
+    post(options: MessageOptions): Message;
+
+    /**
+     * Hides all messages.
+     */
+    hideAll(): void;
+}
+
+interface Message {
+    /**
+     * Show the message, if it's hidden.
+     */
+    show(): void;
+
+    /**
+     * Hide the message, if it's hidden.
+     */
+    hide(): void;
+
+    /**
+     * If the message is associated with an ajax request or is counting down to retry, cancel it.
+     */
+    cancel(): void;
+
+    /**
+     * Update the message with the provided options.
+     */
+    update(options: MessageOptions): void;
+}
+
+interface MessageOptions {
+    /**
+     * The text of the message.
+     */
+    message: string;
+
+    /**
+     * Hide the message after the provided number of seconds.
+     */
+    hideAfter?: number;
+
+    /**
+     * Hide the message if Backbone client-side navigation occurs.
+     */
+    hideOnNavigate?: boolean;
+
+    /**
+     * A unique id. If supplied, only one message with that ID will be shown at a time.
+     */
+    id?: string;
+
+    /**
+     * Should a close button be added to the message?
+     */
+    showCloseButton?: boolean;
+
+    /**
+     * Hide the newer message if there is an id collision, as opposed to the older message.
+     */
+    singleton?: boolean;
+
+    /**
+     * What theme class should be applied to the message? Defaults to the theme set for Messenger in general.
+     */
+    theme?: string;
+
+    /**
+     * "info", "error" or "success" are understood by the provided themes. You can also pass your own string, and that class will be added.
+     */
+    type?: string;
+}
+
+interface MessengerOptions {
+
+    /**
+     * Extra classes to be appended to the container.
+     */
+    extraClasses?: string;
+
+    /**
+     * The maximum number of messages to show at once.
+     */
+    maxMessages?: number;
+
+    /**
+     * Default options for created messages.
+     */
+    messageDefaults?: MessageOptions;
+
+    /**
+     * Which locations should be tried when inserting the message container into the page.
+     * The default is ['body']. It accepts a list to allow you to try a variety of places
+     * when deciding what the optimal location is on any given page. This should generally
+     * not need to be changed unless you are inserting the messages into the flow of the
+     * document, rather than using messenger-fixed.
+     */
+    parentLocations?: string[];
+
+    /**
+     * What theme are you using? Some themes have associated javascript, specifing this allows that js to run.
+     */
+    theme?: string;
+}
+
+declare var Messenger: IMessenger;