How to serve the same page for all URLs? I am using Drupal 7 as an API to send JSON data to a Backbone application. It is a single page site with its HTML markup in html.tpl.php.

Everything works fine with the Backbone router when I start on the homepage and navigate with internal links but when I refresh a page or type a URL directly I get a Drupal 404 error.

How can I make unknown pages to serve the same page all the time?

The .htaccess redirects to index.php so it's not a browser 404 but a Drupal 404.
In case someone has the same issue, it only happens when connected to Drupal's admin panel. I solved it by disconnecting…