---
layout: api
version: 3x
title: Express 3.x - API Reference
description: Access the API reference for Express.js version 3.x, noting that this version is end-of-life and no longer maintained - includes details on modules and methods.
menu: api
redirect_from: "/3x/api.html"
---
<div id="api-doc" markdown="1">

  <div class="doc-box doc-warn" markdown="1">
  **Express 3.x IS END-OF-LIFE AND NO LONGER MAINTAINED**

  Known and unknown security and performance issues in 3.x have not been addressed since the last update (1 August, 2015). It is highly recommended to use the latest version of Express.

  If you are unable to upgrade past 3.x, please consider [Commercial Support Options](/{{ page.lang }}/support#commercial-support-options).
  </div>

  <h1>3.x API</h1>

  {% include api/en/3x/express.md %}
  {% include api/en/3x/app.md %}
  {% include api/en/3x/req.md %}
  {% include api/en/3x/res.md %}
  {% include api/en/3x/middleware.md %}

</div>