Install on IIS

mod_pagespeed runs on IIS as a native, in-process module: the successor to IISpeed. Download the signed MSI, run it, iisreset, and the module optimizes every site that has a pagespeed.config. The IIS package ships as a signed installer on the mod_pagespeed GitHub release.

Machine-readable recipe for coding agents: modpagespeed.com/recipes/iis.md (see Install with a coding agent).

Requirements

• Windows Server 2016 or later, with IIS 10 (the release is tested on Windows Server 2016)
• 64-bit only (the Visual C++ runtime is built in; no redistributable is needed)
• The IIS worker process identity needs write access to the cache directory; the installer grants it for the default directory

Install the module

1. Download the IIS MSI installer from the Download page’s Windows installer link.
2. Check it. On Windows, the MSI’s Authenticode signature is the check for the installer itself: its publisher must be “We-Amp B.V.” (Get-AuthenticodeSignature .\pagespeed-iis-<version>-win-x64.msi reports Valid, with a signer certificate subject starting CN=We-Amp B.V.). The release also carries SHA256SUMS and SHA256SUMS.asc, a GPG signature of the checksum file made with the release signing key, fingerprint 411D EFDB 5713 51D2 B25A EFCC 9C02 B5BD CCE7 5313: the signature verifies SHA256SUMS, and SHA256SUMS then verifies the MSI. The steps are in Verifying a Release. This key is not the one that signs the apt and dnf repositories.
3. Run it on the Windows Server host. The installer registers the module in IIS as a native HTTP module and creates the default cache directory at %ProgramData%\We-Amp\PageSpeed\Cache.
4. Run iisreset.

The module reads pagespeed.config. A site is optimized only when its own physical root holds one; the server-level file at %ProgramData%\We-Amp\PageSpeed\pagespeed.config supplies the defaults for those sites and turns no site on by itself. The installer seeds a per-site copy in the Default Web Site root. The minimal file is two lines:

pagespeed on
pagespeed FileCachePath %ProgramData%\We-Amp\PageSpeed\Cache

IIS configuration documents the file format, the lookup order and path matching.

Coming from IISpeed

If IISpeed is installed on this host, uninstall it before running the MSI. The two modules register the same handler in IIS and cannot coexist. Open Apps & features (or Programs and Features), remove “IISpeed”, run iisreset, then run the installer. Migrate from IISpeed walks through the whole move, configuration and cache included.

The optimizer service

From 2.5.0 on, the installer also installs the optimizer worker, as the Windows service WeAmpPageSpeedOptimizer under its own virtual account, and leaves it disabled: until you turn it on, the module behaves exactly as it does without it. Turned on and pointed at with the DaemonSocketPath and DaemonVolumePath directives, it takes over in-place optimization: the module records each eligible resource, the optimizer builds optimized variants, and the module serves the variant that fits each client. An upgrade or repair with the installer keeps a service you turned on running and keeps the cache size you chose (OPTIMIZERCACHESIZE, 1 GiB by default).

To turn it on:

1. Set the service to start, and start it, from an elevated prompt:

   sc.exe config WeAmpPageSpeedOptimizer start= auto
   sc.exe start WeAmpPageSpeedOptimizer

   Use start= demand instead of start= auto to start it only by hand. The service logs to C:\ProgramData\We-Amp\PageSpeed\logs\optimizer.log; once it is up, the log says it is listening on \\.\pipe\pagespeed-optimizer.

2. Point the module at it. Add these two lines to the server-level C:\ProgramData\We-Amp\PageSpeed\pagespeed.config:

   pagespeed DaemonSocketPath pagespeed-optimizer
   pagespeed DaemonVolumePath "C:\ProgramData\We-Amp\PageSpeed\optimizer\cache"

   DaemonSocketPath is the pipe name the service listens on, without the \\.\pipe\ prefix; the module adds it. DaemonVolumePath is the cache volume’s path stem, …\optimizer\cache: not the optimizer directory the service is given as its cache directory, and not the cache-… file the service creates there.

3. Run iisreset.

The application pools reach the pipe and the cache with the permissions the installer sets; no extra access rules are needed. Start the service before the application pools: the module attaches to the optimizer when a pool starts, so if the service was stopped then, or you start or restart it later, run iisreset again for the module to use it (the module does not reattach on its own yet; tracked in mod_pagespeed#104). To turn the optimizer off, remove the two lines and run iisreset; the module goes back to optimizing on its own.

IIS Express

For local development with IIS Express, add the module to applicationhost.config in %userprofile%\Documents\IISExpress\config\:

1. Copy the module DLL to a known location
2. Add the module registration under <globalModules> and <modules>
3. Restart IIS Express

Verify it works

On IIS the module emits X-Page-Speed, the same header as the nginx module. Check for it with PowerShell:

(Invoke-WebRequest http://localhost/ -UseBasicParsing).Headers["X-Page-Speed"]

Then open /pagespeed_global_admin on the server itself. Is it working? has the other checks.

Next steps

• IIS configuration: pagespeed.config, lookup order, path matching and IIS tuning
• Filter selection: choosing and tuning filters
• Admin console: restricting the admin pages
• Migrate from IISpeed