Enable GZIP Compression in IIS

Enabling Gzip compression in IIS is a great way to reduce response sizes and improve performance for your web applications. In IIS (Internet Information Services), you can enable it either for static content, dynamic content, or both.

Install Dynamic Content Compression

Install the Dynamic Content Compression Feature (if not already installed).

Open Server Manager → Manage → Add Roles and Features

Navigate to: Server Roles > Web Server (IIS) > Web Server > Performance Features

Check:

Dynamic Content Compression
(Static compression is usually installed by default)

Click Next → Install

Enable Compression in IIS Manager

Open IIS Manager
(inetmgr in Run dialog)

In the Connections panel, select your server node (or a specific site if you only want gzip for that site).

Double-click Compression in the middle panel.

In the Actions pane (on the right), check:

Enable static content compression
Enable dynamic content compression

Click Apply.

Verify Configuration

goto: %windir%\System32\inetsrv\config\applicationHost.config

Check that under <system.webServer> you have:

<urlCompression doStaticCompression="true" doDynamicCompression="true" dynamicCompressionBeforeCache="true" />

And for static/dynamic compression modules:

<modules>
  <add name="StaticCompressionModule" type="System.Web.Compression.StaticCompressionModule" />
  <add name="DynamicCompressionModule" type="System.Web.Compression.DynamicCompressionModule" />
</modules>

Test If Gzip Is Working

You can use browser dev tools:

Content-Encoding: gzip

bydev / notes