Open-Source Observability · sitespeedio

sitespeed.io

sitespeed.io is an open-source web performance testing tool that drives real browsers (Firefox, Chrome, Edge, Safari) to measure and report on page load times, Core Web Vitals, and performance bottlenecks. It generates HTML reports with video recordings, HAR waterfalls, and actionable optimization advice, and supports continuous monitoring via integration with Graphite/InfluxDB and Grafana.

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Source: GitHub — github.com/sitespeedio/sitespeed.io

GitHub stars

626

Forks

JavaScript

Primary language

MIT

License (OSI-approved)

Key facts

Objective fields from the source. Values we can't verify are shown as “Unknown” rather than guessed.

Field	Value
Repository	sitespeedio/sitespeed.io
Owner	sitespeedio
Primary language	JavaScript
License	MIT — OSI-approved
Stars	5k
Forks	626
Open issues	158
Latest release	v41.4.1 (2026-07-03)
Last updated	2026-07-08
Source	https://github.com/sitespeedio/sitespeed.io

What sitespeed.io is

JavaScript-based performance analysis tool that orchestrates real browser instances (including mobile devices via USB) to collect Core Web Vitals (LCP, INP, CLS, TTFB, FCP), visual metrics, CPU/long-task analysis, and HAR data. Supports Docker deployment, npm installation, and headless/CI workflows; outputs metrics to JSON, HTML, or timeseries backends (Graphite, InfluxDB).

Quickstart

Get the sitespeed.io source

Clone the repository and explore it locally.

terminalbash

1git clone https://github.com/sitespeedio/sitespeed.io.git2cd sitespeed.io3# follow the project's README for install & configuration

Need it deployed, integrated, or customized instead? DEV.co ships production installs.

Best use cases

Pre-release regression testing in CI/CD

Run on every PR with performance budgets; fail the build if metrics exceed thresholds. Catches performance regressions before production.

Continuous production monitoring dashboard

Schedule recurring tests, ship metrics to Graphite/InfluxDB, visualize trends in Grafana. Monitor real-world performance over time across browsers and environments.

Ad-hoc page audit and debugging

Terminal-based single-run audit generates rich HTML reports with filmstrips, video, waterfall, and Coach advice. Quick way to identify what's slow on a page.

Implementation considerations

Browser and system dependencies (FFmpeg, Python) must be installed or Docker must be available; Docker image is recommended for reproducibility.
Mobile testing (Android/iOS) requires USB-connected physical devices and platform-specific setup (ADB for Android, Xcode tools for iOS).
For continuous monitoring, plan infrastructure for test runners, result storage (Graphite/InfluxDB), and Grafana visualization.
Performance budgets and thresholds should be configured early; baseline measurements required before enforcing CI/CD gates.
Test iterations (e.g., `-n 5`) needed for statistical significance; single runs are noisy and may produce misleading results.

When to avoid it — and what to weigh

You need SLA-backed commercial support contracts — This is community-maintained open-source software. No guaranteed SLA, vendor support, or indemnification clauses available.
You require synthetic monitoring with managed infrastructure — sitespeed.io is self-hosted and requires you to provision and maintain test environments (servers, browsers, dependencies). No managed SaaS option.
You need real user monitoring (RUM) data — sitespeed.io collects synthetic metrics only. Does not instrument production JavaScript to capture actual user experience.
Your team cannot manage browser dependencies and system resources — Requires Firefox, Chrome, Edge, or Safari installed plus FFmpeg and Python. Docker simplifies this, but Docker infrastructure must be managed separately.

License & commercial use

MIT License (permissive OSI-approved open-source license). Allows commercial use, modification, and distribution with minimal restrictions; requires attribution and liability disclaimer.

MIT License permits commercial deployment without fee or license restriction. However, no vendor support, warranties, or indemnification provided. Commercial users must manage own infrastructure, support, and compliance. Recommend internal review for liability/insurance posture if performance metrics directly inform business decisions.

DEV.co evaluation signals

Editorial assessment — not user reviews. Directional, with an explicit confidence level.

Signal	Assessment
Maintenance	Active
Documentation	Strong
License clarity	Clear
Deployment complexity	Moderate
DEV.co fit	Strong
Assessment confidence	High

Security considerations

Data remains on-premises (no cloud upload by default). Docker image has security scan workflow in CI/CD. Users must secure: test runner infrastructure, result storage (Graphite/InfluxDB credentials), and Grafana dashboards. No built-in encryption or auth for metrics backend; rely on network isolation or reverse-proxy authentication. Browser automation executes scripts; review user-provided test scripts for injection risks.

Alternatives to consider

Lighthouse (Google)

Lighter-weight, Google-maintained, focuses on Core Web Vitals and best practices. No video/waterfall; single-run only (no multi-iteration baseline). Integrated into DevTools and CI tools (PageSpeed Insights). Free, no infrastructure overhead.

WebPageTest

Established SaaS platform with global test infrastructure. Offers film strip video, waterfall, filmstrip. Managed service (no self-hosting complexity) but requires subscription and sends data off-premises. Broader geographic test locations.

Speedcurve (formerly SpeedCurve)

Commercial SaaS for continuous performance monitoring. Managed infrastructure, visual regression, filmstrip video. No self-hosting, vendor-backed support. Higher cost but lower operational burden.

Software development agency

Build on sitespeed.io with DEV.co software developers

sitespeed.io is free and self-hosted. Start with a single audit, then graduate to continuous monitoring. Review the documentation and deployment guide to plan your test infrastructure.

Talk to DEV.co

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sitespeed.io FAQ

Can I run sitespeed.io in a headless CI/CD pipeline without a display server?

Yes. Docker image includes headless Firefox and Chrome; use `--headless` flag (or deploy in Docker). This is the recommended approach for CI/CD.

What happens if performance exceeds my budget threshold?

Exit code is non-zero; build fails. Configure budgets via command-line flags (e.g., `--budget`). Useful for enforcing SLOs in CI/CD gates.

Does sitespeed.io measure real user experience or just synthetic tests?

Synthetic only. It runs automated test scripts in controlled browsers. For actual user metrics (RUM), integrate with Google Analytics, Real User Monitoring tools, or custom instrumentation.

How do I set up continuous monitoring with Grafana?

Schedule sitespeed.io runs (cron or CI/CD), configure output to Graphite or InfluxDB, then build Grafana dashboards querying those backends. See documentation for examples.

Custom software development services

DEV.co is a software development agency delivering custom software development services to companies building on open source. Our software developers and web developers design, integrate, and ship production systems — spanning web development, APIs, AI, data, and cloud. If sitespeed.io is part of your open-source observability roadmap, our team can implement, customize, migrate, and maintain it.

Ready to measure and monitor web performance?

sitespeed.io is free and self-hosted. Start with a single audit, then graduate to continuous monitoring. Review the documentation and deployment guide to plan your test infrastructure.

Talk to DEV.co Schedule a Consultation