SiteSpeed.io

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Introduction

sitespeed.io is an open-source toolset for analysing and monitoring website speed and performance, based on performance best practices. The project is at sitespeedio/sitespeed.io on GitHub under the MIT licence, with about 5,000 stars; the latest release at review was v42.10.0 (23 October 2026), and the repository had commits in November 2026.

It drives real browsers (Chrome, Firefox, Edge and Safari on supported platforms) with its Browsertime engine, records video and visual metrics, collects Core Web Vitals and other timings, and analyses pages against best-practice rules with its Coach. Results can be stored in Graphite or InfluxDB and visualised in Grafana dashboards that the project provides, making it a self-hosted alternative to commercial performance monitoring. The site emphasises privacy: you run it yourself, so data stays with you.

You can run sitespeed.io from Docker (the recommended way, with browsers preinstalled) or npm, and it supports scripted user journeys, mobile testing on Android phones, and plug-ins such as Lighthouse and WebPageTest integration.

How it compares: Lighthouse is a single-run audit, while sitespeed.io is built for repeated measurement and monitoring over time. Commercial tools such as SpeedCurve and DebugBear provide the same idea as hosted SaaS with less setup.

In the quality loop sitespeed.io covers the performance stage and can gate releases with performance budgets.

Features

1. Real browser testing: Browsertime drives Chrome, Firefox and other browsers.
2. Visual metrics and video: Filmstrips and visual progress metrics.
3. Coach best-practice advice: Rule-based performance advice.
4. Grafana dashboards: Ready-made dashboards with Graphite or InfluxDB.
5. Performance budgets: Fail builds when metrics exceed budgets.
6. Scripting and mobile: Multi-step journeys and Android device testing.
7. Docker and npm: Easy installation with Docker images.

Pros

1. Free and open source: MIT licence, self-hosted.
2. Active project: Frequent releases.
3. Privacy: Data stays on your infrastructure.

Cons

1. Setup and maintenance: Running dashboards and storage takes effort.
2. Expertise needed: Interpreting metrics benefits from performance knowledge.

Usage and Links (Example)

Run a quick test with Docker:

docker run --rm -v "$(pwd):/sitespeed.io" sitespeedio/sitespeed.io https://www.sitespeed.io/

For monitoring, schedule runs from a server, send metrics to Graphite or InfluxDB, and import the project’s Grafana dashboards. Add a budget file to fail CI when metrics regress.

Useful links:

• Documentation
• GitHub repository

Pricing

Free and open source under MIT. Infrastructure costs are yours.

Recommended for?

• Teams that want self-hosted performance monitoring
• Privacy-conscious organisations that cannot send data to SaaS tools
• Performance engineers who want real-browser metrics and budgets in CI

Conclusion

sitespeed.io is a mature, actively maintained open-source performance toolkit that can replace commercial monitoring for teams willing to run it. Its real-browser metrics, budgets and dashboards make it a strong choice for continuous performance testing.