Sitespeed.io
How speedy is your website·sitespeed.io
Sitespeed.io is an open source web performance tool that analyses and optimises website speed based on performance best practices. Run once, it produces an HTML report with Core Web Vitals, a video of the page loading, a HAR waterfall, and Coach advice on what to fix. Run on a schedule, it ships metrics to Graphite or InfluxDB to build a Grafana dashboard tracking site performance over time. It has been available since 2012, is free, requires no signup, and users own all their data.
What it's for
Features 20
- Chrome HAR generation via Chrome Debugging Protocol (Chrome-HAR)
- Coach performance advice
- Convert HAR files to usable format (PageXray)
- Core Web Vitals measurement (LCP, INP, CLS, FCP, TTFB)
- CPU main-thread timeline capture
- Docker container with Firefox, Chrome, Edge, XVFB pre-installed
- Grafana dashboard integration
- HAR file comparison (Compare tool)
- HAR waterfall visualization
- HTML report with Core Web Vitals
- Metrics shipping to Graphite or InfluxDB
- Network throttling (e.g. 4G profile)
- npm global install
- Raspberry Pi WiFi network link conditioner (Humble)
- Scripting API for user journeys
- Simulate slow network connections (Throttle)
- Testing on real Android phones
- Testing on Safari on iOS
- Video recording of page load
- Visual metrics via video
At a glance
Integrations
Resources
Pricing
The tool itself is free; running it incurs infrastructure costs only (estimated ~$500/year for a cloud instance plus S3 storage), not a vendor fee.
Free and open source software; the only cost is infrastructure to run it and store results, estimated around $500/year on a single cloud instance plus S3 storage.