What is Browsertime?
Browsertime is an open-source CLI tool from Sitespeed.io that drives real browsers (Chrome/Firefox) via Selenium WebDriver to capture detailed performance metrics, paint timing, CPU/network throttling, video recording. Lower-level than Sitespeed.io itself (Sitespeed.io wraps Browsertime). Where it falls short for teams that need a hosted solution: Browsertime is a CLI you operate yourself, you provision infrastructure for the browsers, manage WebDriver configurations, parse JSON output, build your own dashboards and alerting. The detail is excellent but the operational overhead is real.
When Browsertime is the right pick
- You're a performance researcher who needs fine-grained control over browser conditions (CPU throttling, network shaping).
- You need video recording + filmstrip generation for visual regression analysis.
- You have devops skill to operate a Selenium-based perf-testing pipeline locally or in CI.
Where Browsertime leaves gaps
- Pure CLI, no hosted dashboards. You parse JSON output and build visualizations yourself.
- Selenium WebDriver setup. Manage browser drivers, version-pin Chrome/Firefox, handle Docker images.
- No scheduling. Cron + script wrapping required.
- No alerts. Wire output to Grafana/Slack manually.
- No load testing. Browsertime measures one user's experience; doesn't simulate concurrent traffic.
LoadFocus vs. Browsertime: comparison
| Feature | LoadFocus | Browsertime |
|---|---|---|
| Core Web Vitals + Lighthouse | Yes, hosted, scheduled | Yes (CLI, DIY) |
| Hosted infrastructure | Yes. SaaS | No (you operate it) |
| Built-in dashboards | Yes | No (JSON output, build your own) |
| Scheduled runs | Yes, hourly/daily/weekly | Cron, DIY |
| Alerts on regression | Yes, email/Slack/webhook | DIY wiring |
| Video recording / filmstrip | Some Lighthouse traces | Yes (Browsertime's strength) |
| Fine-grained CPU/network throttling | Standard mobile/desktop profiles | Yes (configurable) |
| JMeter/k6 load testing | Yes | No |
| Pricing | Flat SaaS, ~$19/mo | Free (OSS) + infra costs |
When LoadFocus is the right pick
- You want hosted Lighthouse + CWV: no Selenium/Docker plumbing.
- You need scheduled runs + dashboards + alerts out of the box.
- You want load testing in addition to perf monitoring.
- You don't need video recording / filmstrip analysis (Browsertime's specialty).
- You're not a perf researcher: you just need to monitor pages over time.
Migrating from Browsertime
- Inventory existing Browsertime scripts/configs: URLs tested, browser conditions, frequency.
- Configure equivalent scheduled Lighthouse runs in LoadFocus: most browser conditions (mobile/desktop, throttling profile) have direct equivalents.
- Migrate dashboards: LoadFocus's built-in dashboards cover the same core metrics (LCP, CLS, INP, etc.) without DIY JSON parsing.
- If you need video recording / filmstrip, keep Browsertime locally for those specific use cases. LoadFocus's Lighthouse data covers the most common needs without the video overhead.
- Add load testing: Browsertime has none. LoadFocus runs JMeter/k6 in the cloud.
FAQ: LoadFocus vs Browsertime
Does LoadFocus do video recording like Browsertime?
Lighthouse traces include some visual data (filmstrip-style screenshots at key moments). Full continuous video recording is Browsertime's specialty, for that specific need, keep Browsertime locally.
Can I run LoadFocus from my private network like Browsertime CLI?
No. LoadFocus is SaaS-only, tests public URLs. For intranet/VPN-only sites, Browsertime self-hosted is the right tool.
Is LoadFocus cheaper than running Browsertime myself?
Usually yes once you count infra costs + engineering time. LoadFocus at ~$19/mo flat replaces a $50-200/mo DIY infrastructure stack + ongoing maintenance time.
Does LoadFocus support fine-grained network/CPU throttling like Browsertime?
Standard mobile/desktop Lighthouse profiles are built-in. For arbitrary custom throttling (e.g., flaky 2G with packet loss), Browsertime's CLI flexibility wins.
Can I keep Browsertime for research and add LoadFocus for monitoring?
Yes, common pattern. Browsertime for deep perf research + visual analysis, LoadFocus for scheduled monitoring + alerting + dashboards.
What about Sitespeed.io (which wraps Browsertime)?
Sitespeed.io is the higher-level CLI built on Browsertime. See the dedicated Sitespeed.io alternative page for that comparison. Both Sitespeed.io and Browsertime are self-hosted CLI tools; LoadFocus is the hosted alternative.
Get started with LoadFocus
Sign up free and create your first scheduled Lighthouse audit, hosted, no Selenium, no Docker, no DIY dashboards.
