Hi everyone!

We’re getting ready to push some major updates over the next few weeks, and we wanted to give you a heads-up on changes to our custom theme engine.

We’ve tried to make Tumblr themes as open and customizable as possible, and the things you’ve created have blown our minds.  But there are still things we’ve wanted to do that haven’t been easy enough.

So next Monday we’ll be scrapping our old code for a completely overhauled template engine.  We’re seriously excited about this, and we can’t wait to see what you’re able to do with it.

The most noticeable improvements:

• The new engine is scoped, so you’ll be able to nest and repeat blocks and variables.
• The engine uses a new token parser that will support special syntax for API hooks. This will let your theme call back for content, like:

  {​block:Posts type="photo" tagged="spotlight" count="5"}
      <img src="{​PhotoURL width="200"}" />
  {/block:Posts}

We’ve been systematically testing the new engine to make sure it’s backwards compatible.  You can test it yourself by adding ?beta=1 to any tumblelog URL (e.g. http://www.davidslog.com/?beta=1).  If it’s working correctly, you shouldn’t see a difference.

Please let us know if you see anything funny.