I've already read about mime types in wordress and how to add them, but I can't find any documentation about the correct type of files. For e.g. after a lot of research I find out that the epub extension has a application/epub+zip file type, but how to get other unknown files like .blend or .xcf to work?

The following pseudocode illustrates the problem:

function custom_mime_types($mime_types){

    //Adding unknown extension 
    $mime_types['unknownextension'] = 'typeoffile'; 
    return $mime_types;

add_filter('upload_mimes', 'custom_mime_types', 1, 1);

Is there a Documentation about it?


1 Answer 1


You can use this function as you mentioned and you need to learn your file extensions mime type (in example i add svg and xcf upload ability to wordpress)

add_filter('upload_mimes', 'ability_to_upload');

function ability_to_upload($mimes = array()) {
    $mimes['svg'] = 'image/svg+xml';
    $mimes['xcf'] = 'image/xcf';
    return $mimes;

Here is a link for mime types list and file extension checker (you can search by file extension)

  • Thanks Serkan, mime types list is helpfull! Sorry cant upvote you. But what about the blend-file?
    – p2or
    Commented Oct 14, 2014 at 13:27
  • You are welcome :) No problem with upvote, but you can select answer is right i think. i couldn't find blend file mime type either. Commented Oct 14, 2014 at 18:04
  • Comment after 3 years :D .blend mime-type is application/x-blender :) Commented Nov 28, 2017 at 15:00

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