---
layout: default
title: Arduino Client for MQTT
---
   <p>This library provides a client for doing simple publish/subscribe messaging with a server that supports MQTT</p>
   <p>For more information about MQTT, visit <a href="http://mqtt.org">mqtt.org</a>.</p>

   <section id="Download">
      <h2>Download</h2>
      <p>The latest version of the library can be downloaded from <a href="https://github.com/knolleary/pubsubclient/releases/latest">GitHub</a>.</p>
   </section>
   <section id="Documentation">
      <h2>Documentation</h2>
      <p>The library comes with a number of example sketches. See <code>File &gt; Examples &gt; PubSubClient</code> within the Arduino application.</p>
      <p>Full <a href="api.html">API Documentation</a></p>
   </section>
   <section id="Hardware">
       <h2>Compatible Hardware</h2>
       <p>
           The library uses the Arduino Ethernet Client api for interacting with the
           underlying network hardware. This means it Just Works with a growing number of
           boards and shields, including:
       </p>
       <ul>
            <li>Arduino Ethernet</li>
            <li>Arduino Ethernet Shield</li>
            <li>Arduino YUN – use the included <code>YunClient</code> in place of <code>EthernetClient</code>, and
                be sure to do a <code>Bridge.begin()</code> first</li>
            <li>Arduino WiFi Shield - if you want to send packets greater than 90 bytes with this shield,
   enable the <a href="http://knolleary.github.io/pubsubclient/api.html#configoptions"><code>MQTT_MAX_TRANSFER_SIZE</code></code></a> option in <code>PubSubClient.h</code>.</li>
            <li>Sparkfun WiFly Shield – when used with <a href="https://github.com/dpslwk/WiFly">this library</a></li>
            <li>Intel Galileo/Edison</li>
            <li>ESP8266</li>
            <li>ESP32</li>
        </ul>
        <p>
            The library cannot currently be used with hardware based on the ENC28J60 chip –
            such as the Nanode or the Nuelectronics Ethernet Shield. For those, there is an
            <a href="https://github.com/njh/NanodeMQTT">alternative library</a> available.
        </p>
    </section>

    <section id="Author">
       <h2>Author</h2>
       <p>Nick O'Leary - <a href="https://twitter.com/knolleary">@knolleary</a></p>
    </section>
    <section id="License">
       <h2>License</h2>
       <p>This library is released under the <a href="http://www.opensource.org/licenses/mit-license.php">MIT License</a>.</p>
    </section>
   <section id="ChangeHistory">
      <h2>Change History</h2>
      <p>The complete change history is available on <a href="https://github.com/knolleary/pubsubclient/commits/master">GitHub</a>.</p>
      <dl>
          <dt>2.7</dt>
          <dd>
              <ul>
                  <li>Fix remaining-length handling to prevent buffer overrun</li>
                  <li>Add large-payload API - beginPublish/write/publish/endPublish</li>
                  <li>Add yield call to improve reliability on ESP</li>
                  <li>Add Clean Session flag to connect options</li>
                  <li>Add ESP32 support for functional callback signature</li>
                  <li>Various other fixes</li>
              </ul>
          </dd>
      </dl>
  </section>