Code Quality
webhookbeam.com
Set up webhooks and monitor them via push notifications and emails
checkbot.io
Browser extension that tests if your website follows 50+ SEO, speed and security best practices. Free tier for smaller websites
gridlastic.com
Selenium Grid testing with a free plan of up to 4 simultaneous selenium nodes/10 grid starts/4,000 test minutes/month
UseWebhook.com
Capture and inspect webhooks from your browser. Forward to localhost, or replay from history. Free to use
lambdatest.com
Manual, visual, screenshot, and automated browser testing on selenium and cypress, free for Open Source
everystep-automation.com
Records and replays all steps made in a web browser and creates scripts, free with fewer options
browserstack.com
Manual and automated browser testing, free for Open Source
websitepulse.com
Various free network and server tools
Blackfire.io
Performance testing
testingbot.com
Selenium Browser and Device Testing, free for Open Source
katalon.com
Provides a testing platform that can help teams of all sizes at different levels of testing maturity, including Katalon Studio, TestOps (+ Visual Testing free), TestCloud, and Katalon Recorder
tesults.com
Test results reporting and test case management. Integrates with popular test frameworks. Open Source software developers, individuals, educators, and small teams getting started can request discounted and free offerings beyond basic free projects