I posted this on the talk page for the API. Trying to find an answer. I did try with 16.5, but still the same error, it is reporting a doubled Content-Length. Where in the code is the header formed for content length? Or is it relying on server? Doubled Content-Length in HTTP Header MediaWiki version: 16.0 - also tried 16.5 PHP version: 5.2.17 (cgi) MySQL version: 5.0.91-log URL: www.isogg.org/w/api.php I am trying to track down a bug in the api which is causing a double content-length in the header. This is causing a lot of issues with a python bot. Here is the report from web-sniffer showing the content of the api.php call from this wiki. All other pages when called, i.e. the Main page, etc. only report 1 content-length. Is the api forcing the headers? Why is doubling only the one? Status: HTTP/1.1 200 OK Date: Mon, 30 Jan 2012 14:31:25 GMT Content-Type: text/html; charset=utf-8 Connection: close Server: Nginx / Varnish X-Powered-By: PHP/5.2.17 MediaWiki-API-Error: help Cache-Control: private Content-Encoding: gzip Vary: Accept-Encoding Content-Length: 16656 Content-Length: 16656 As you can see this is a Nginx server. On an Apache server with 16.0, only one content-length is sent. Could that be the issue and how do I solve it? Thanks. Tom