Directory
Playwright
Cross-browser E2E testing
FreeCode review, testing & securityplaywright.dev
What it is
End-to-end test framework covering Chromium, WebKit and Firefox on Windows, Linux and macOS, bundling a runner, assertions, test isolation and parallelisation. Auto-waiting eliminates most flaky timing failures. It ships a trace viewer for post-mortem debugging, codegen for recording tests, and an MCP server for agent-driven browser control.
Why it earns a slot
The only layer that proves the app actually works end to end. AI-written code routinely type-checks and passes unit tests while the real login or checkout flow is broken; a browser test is what catches that.
Getting started
npm init playwright@latest
Neighbourhood
How Playwright sits against the rest of the atlas — swaps, companions and the tools builders actually save alongside it.
Also in Code review, testing & security
Aikido Security
aikido.devNot yet swept
All-in-one AppSec scanner
Free tier + paidCode review, testing & security
Developer free forever: 2 users, 10 repos, 2 container images, 1 domain, 250k protected requests/mo, 10 AI autofixes/mo; Basic $300/mo base for 10 users and 100 repos; Pro $600/mo for 200 repos; Advanced $600/mo for 500 repos; Enterprise custom
Open dossier
Arcjet
arcjet.comNot yet swept
In-app rate limiting and bot defence
PaidCode review, testing & security
No free plan as of 2026; Individual $25/app/mo; Startup $299/app/mo; Growth $799/app/mo; usage fees on top at $5 per 1M requests plus per-feature rates such as $0.50 per 1M for bot detection; 15-day trial
Open dossier
Bito
bito.aiNot yet swept
AI PR review agent
PaidCode review, testing & security
Team $12/seat/mo annually or $15 monthly; Professional $20/seat/mo annually or $25 monthly; both include 5,000 lines reviewed per seat per month, overage $5 per 1,000 lines; Enterprise custom; 14-day trial
Open dossier
Browserbase
browserbase.comNot yet swept
Hosted headless browser cloud
Free tier + paidCode review, testing & security
Free: 1 browser hour/mo; Developer $20/mo with 100 browser hours then $0.12/hr; Startup $99/mo with 500 hours then $0.10/hr; Scale custom with 250+ concurrent browsers
Open dossier