Welcome to the wonderful world of Web Performance is a set of Open Source tools that helps make your web pages faster. The coach gives you performance advice based on best practices for your site. Browsertime collects metrics and HAR files from your browser. PageXray converts a HAR file to a usable JSON structure that tells you more about your page. Chrome-HAR creates a HAR file Chrome Debugging Protocol data. And finally is the main tool that uses all the previously mentioned tools and add supports for testing multiple pages as well as adds the ability to report the metrics to a TSDB (Graphite and InfluxDB).

Try out by installing using Docker/npm/yarn (need help?):


$ docker run --shm-size=1g --rm -v "$(pwd)":/ sitespeedio/ --video --speedIndex


$ npm install -g
$ -h 5.0

With the latest release we add support for storing metrics in InfluxDB, add your own request headers, block requests by domain and a massive HTML update. Read the blog post to find out more.

Be a performance hero!

Pippi Longstocking a true hero

With it’s easy to become a performance hero! Check out our example dashboard, it’s a great example that shows you what you can do. It’s super easy to get that up and running. You can even use our new Docker Compose file to get Graphite/InfluxDB/Grafana with default dashboards up and running in less than 5 minutes!

There’s a new Coach in town

I'm the coach

The Godfather of web performance tools YSlow is dead. It died a couple of years after the first release and finally there’s something new that can guide you in the web performance jungle: The Coach gives you advice on how you can make your web page more performant.

Docker to the rescue!

Use our Docker container to get an environment with Firefox, Chrome, XVFB and up and running as fast as you can download them.

$ docker pull sitespeedio/
$ docker run --rm -v "$(pwd)":/ sitespeedio/ -b firefox --speedIndex --video

To set the connectivity follow our connectivity guide for Docker.

Use 5.0!

  • Collect timing metrics, video, screenshots and page metrics in one go
  • Run Firefox and or Chrome
  • Super simple setup with Docker
  • Generic dashboard templates for Grafana
  • The coach is the new YSlow
  • Write your own plugins
  • HAR files as seen by the browser

Browsertime 1.0


We’ve been working on releasing 1.0 of Browsertime for some time and now it’s here! You should use Browsertime if you want a raw JSON result for timings and/or execute your own JavaScript. Browsertime is perfect if you wanna build your own performance tool, as VoxMedia did when they created Lightbike built on top of Browsertime.

Thank you! is built upon Open Source tools, we have a special place in our hearts for those projects (see the full list):


There’s a lot of things you can do to help us make even better than it is today.

If you code, write documentation or do UX you can check the help section and the full issue list.

These people has already improved with pull requests or ideas (massive love!).