IIS7 dynamic compression doesn't compress JSON by default

Enabling dynamic and static compression in IIS7 is easy, well-documented, and beneficial for performance in almost every scenario.

However, compression of JSON data is not enabled by default.

Here's how to enable it:

c:\windows\system32\inetsrv\appcmd.exe set config -section:system.webServer/httpCompression /+"dynamicTypes.[mimeType='application/json',enabled='True']" /commit:apphost


(Your drive letter and windows folder may be different than my example above.)

Then recycle your app pools ... and you're done.