Needle

github.com

What it is

Needle tests CSS and other web visuals by comparing screenshots with known good screenshots.

From github.com's own pages, read 10 Oct 2026.

As github.com lists them, read 10 Oct 2026.

Data plate

Price: Free to use
Free plan: Yes
Free trial: Not stated
Runs on: Linux
Open source: No
Website: github.com
Additional checks: It also provides tools for testing calculated CSS values and HTML element positions.
Baseline workflow: Tests can save an initial screenshot as a baseline and compare later captures against it to detect regressions.
Browser automation: Needle works with Selenium and nose.
Browser drivers: The documentation lists NeedleRemote, NeedlePhantomJS, NeedleFirefox, NeedleChrome, NeedleIe, NeedleOpera, and NeedleSafari drivers.
Cleanup: Screenshot cleanup after successful tests is optional and disabled by default.
Cleanup behavior: Screenshot files are kept by default after successful tests, with an option to delete them; screenshots from failing comparisons remain available for inspection.
Comparison engines: The documented screenshot engines are PIL, PerceptualDiff, and ImageMagick; PerceptualDiff and ImageMagick can produce diff images when tests fail.
Default driver: The documentation says Needle uses NeedleFirefox by default.
Checked: 10 Oct 2026

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