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IISpeed alternative

IISpeed is deprecated because We-Amp consolidated two IIS code paths into one (mod_pagespeed 1.15). Existing customers get a free license transfer. IISpeed was We-Amp's native IIS port of mod_pagespeed, first released in 2012 — image optimization, CSS/JS minification, and critical CSS injection on the IIS pipeline for Windows-hosted sites.

Download & run mod_pagespeed for IIS Support plans Transfer my IISpeed license

Open source under the Apache License 2.0 — free in development and in production.

IISpeed is now deprecated. Existing customers get a free license transfer to either mod_pagespeed (native IIS port) or to the WeAmp.PageSpeed.AspNetCore NuGet package for ASP.NET Core. Existing installations keep working with ongoing support, but IISpeed itself no longer receives updates: its IIS integration lives on in the mod_pagespeed IIS module.

This page explains both forward paths.

What IISpeed was

IISpeed wrapped the mod_pagespeed optimization libraries in an IIS module ( IISpeedModule.dll) that registered against the IIS request pipeline. Configuration sat in web.config under <system.webServer>. Filters, variants, and the admin console all worked the same way as the Apache and nginx ports.

Customers ran it on Windows Server 2008 R2 through 2019. The IIS module ABI stayed compatible across those releases.

Why it's deprecated

  • The .NET 4 and IIS 7-era toolchain is increasingly painful to build and test against modern Windows.
  • The current image pipeline (WebP variants), Core Web Vitals signals, and the newer variant fan-out never landed in the IISpeed build.
  • Customer demand consolidated on either drop-in IIS replacements (where 1.15 fits) or on ASP.NET Core (where the WeAmp.PageSpeed.AspNetCore NuGet package fits).
  • One IIS code path is better than two. The IIS port now lives inside mod_pagespeed, shared with the Apache and nginx ports.

Path 1 — mod_pagespeed for IIS

If you have an IIS deployment and want a drop-in replacement, mod_pagespeed for IIS is a native IIS port with the same module surface IISpeed offered. Same web.config syntax, a modernized, secured filter stack with new optimizers, same admin console — plus security patches, current toolchain, and Cyclone Cache. 

<!-- web.config -->
<system.webServer>
  <modules>
    <add name="ModPagespeedModule" type="ModPagespeed.IIS.Module, ModPagespeed.IIS" />
  </modules>
  <pagespeed enabled="true">
    <fileCachePath>C:\inetpub\modpagespeed\cache</fileCachePath>
  </pagespeed>
</system.webServer>

The MSI installer from the downloads page registers the module, creates the cache directory, and warm-starts the worker.

mod_pagespeed docs · IIS migration guide · Download the MSI

Path 2 — WeAmp.PageSpeed.AspNetCore NuGet package for ASP.NET Core

If your stack is ASP.NET Core, IIS is no longer the natural integration point. The WeAmp.PageSpeed.AspNetCore NuGet package is ASP.NET Core middleware: it runs inside your app's request pipeline, with no separate reverse proxy: 

// Program.cs
using WeAmp.PageSpeed.AspNetCore;

var builder = WebApplication.CreateBuilder(args);
builder.Services.AddPageSpeed();

var app = builder.Build();
app.UsePageSpeed();
app.Run();
dotnet add package WeAmp.PageSpeed.AspNetCore

No IIS module registration, no web.config editing, no gacutil. It targets .NET 8 and .NET 10 on Linux (x64, arm64), macOS (Apple Silicon) and Windows (x64).

How the integration works · NuGet package

Which path fits

Use case Choose
Classic ASP.NET / WebForms / MVC 5 on IIS mod_pagespeed for IIS
Existing IISpeed install you want to keep running with security patches mod_pagespeed for IIS
ASP.NET Core (.NET 8 or 10) on Kestrel WeAmp.PageSpeed.AspNetCore NuGet package
Linux container deployment of an ASP.NET Core app WeAmp.PageSpeed.AspNetCore NuGet package
ASP.NET Core hosted on Windows / IIS WeAmp.PageSpeed.AspNetCore NuGet package (it runs on Windows x64), or mod_pagespeed for IIS
Mixed environment (some sites on classic IIS, some on .NET Core) Run both side by side, each configured its own way (pagespeed.config on IIS, appsettings.json in ASP.NET Core)

License transfer

If you hold an IISpeed license, request the transfer through the license-transfer form, with your order number or the email address the license was bought under. The transfer is at no cost: paid terms are honored to expiry, and you keep your current rate when you move to a support subscription. No new license is needed; the software is free to install and run. Other questions go to info@we-amp.com. The IISpeed transition is documented at iispeed.com.

Frequently asked questions

Is IISpeed still supported?

Existing IISpeed installations keep working with ongoing support, but IISpeed itself no longer receives updates: its IIS integration lives on in the mod_pagespeed IIS module. New IIS deployments should use mod_pagespeed for IIS, and ASP.NET Core deployments the WeAmp.PageSpeed.AspNetCore NuGet package.

I hold an IISpeed license. What do I need to do?

Request the transfer through the license-transfer form at https://modpagespeed.com/contact/?topic=iispeed-transfer, with your order number or the email address the license was bought under. The transfer is at no cost: paid terms are honored to expiry, and you keep your current rate when you move to a support subscription. No new license is needed; the software is free to install and run. Other questions go to info@we-amp.com.

What replaces IISpeed for IIS deployments?

mod_pagespeed ships a native IIS module with the same web.config surface IISpeed offered — a modernized, secured filter stack with new optimizers, same admin console, plus security patches, current toolchain, and Cyclone Cache. The IIS package ships as a signed installer on the mod_pagespeed GitHub release.

Does WeAmp.PageSpeed.AspNetCore work with classic ASP.NET?

WeAmp.PageSpeed.AspNetCore is for ASP.NET Core. For classic ASP.NET / WebForms / MVC 5 on IIS, mod_pagespeed for IIS is the right path — it's an IIS module, no application code changes required.

Can I run both mod_pagespeed for IIS and the WeAmp.PageSpeed.AspNetCore package?

Yes. Both can run side by side, each configured its own way: pagespeed.config directives on IIS, appsettings.json settings in ASP.NET Core.

Install and run

Install either path and it optimizes right away. mod_pagespeed is open source under the Apache License 2.0 — free in development and in production.

The IIS package ships as a signed installer on the mod_pagespeed GitHub release.

Related

IIS, ASP.NET, Windows Server, and other product names are trademarks of their respective owners. mod_pagespeed is an open-source project originally developed at Google; its maintained continuation, mod_pagespeed 2, is developed by We-Amp B.V. Comparisons reflect publicly available information as of 2026 and are provided for evaluation; We-Amp B.V. is not affiliated with or endorsed by Microsoft Corporation or Google.

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