Creating a custom login form for Basecamp

gistfile1.html

<form action="https://launchpad.37signals.com/session" method="post">
  <input name="product" value="basecamp" type="hidden" />
  <input name="account_id" value="#######" type="hidden" />

  <p>Username<br />
  <input name="username" id="username" type="text" /></p>

  <p>Password<br />
  <input name="password" id="password" type="password" /></p>

  <p><label><input name="remember_me" id="remember_me" value="1" type="checkbox" />
    Remember me on this computer
  </label></p>

  <p><input name="submit" value="Sign in" type="submit" /></p>
</form>

Notes:

The Account ID is different from the number in your account URL.

To get the Account ID, log out of Basecamp, and then go to your Basecamp address again. 
This will redirect you to a launchpad address like:

https://launchpad.37signals.com/basecamp/######/signin

That ###### is your Account ID.

This form will not work for Basecamp Classic. We have info on login forms for our other products: 
https://gist.github.com/255012