Premailer is a Python library for turning a HTML + CSS into HTML with all the CSS embedded as inline style attributes. This is sadly very necessary to ensure that your fancy HTML emails look spiffy across all email clients and email webapps.
So, last week I put together a little site to test the library via a browser: Premailer.io
It's just a simple webapp with a form where you can enter HTML in three different ways; textarea, by URL and by file upload.
You can also override all the possible advanced options that premailer supports.
What's kinda cool is that you can get a preview of how the HTML document will look like in an iframe that is dynamically loaded with the result from the conversion.
The webapp is of course open source and available on github.com/peterbe/premailer.io. The front-end is an AngularJS app and the build system is Lineman.js. The server is a Falcon server running on uWSGI via Nginx.
There's very little fancy here. There's no limitations or protections. I just hope it becomes handy for people to test premailer out.
The inspiration came from MailChimp's CSS Inliner Tool which is cute but very basic and doesn't allow you the same kinds of input.
If anybody with some AngularJS or highlight.js chops has time I'd love to help fix why the HTML is not syntax highlighted.