I'm using the JSON API with WP Super Cache. Super Cache needs the generated file to end with '</html>' in order to recognize the end of the file and cache the page. I modified the JSON API plugin to add '//</HTML>' to the end of the JSON string, and then used a filter on WP Super Cache to remove the '//</HTML>' after caching so the JSON string remains unmodified. It works great, my JSON data loads super fast now!
I'd prefer if I could use a filter to modify the JSON string rather than hacking the plugin, so my changes don't get overwritten on plugin updates. Thanks for an awesome plugin.