Contrast Auditor — WCAG Colour Contrast Checker

Find every colour contrast failure on a page and check it against WCAG 2.2 AA and AAA. Nothing leaves your browser.

Contrast failures are the single most common WCAG failure on the web — WebAIM's annual survey of the top million home pages finds low-contrast text on more than four pages in five. Contrast Auditor finds every one of them on the page you are looking at, in one click. What it checks - Every visible text node against WCAG 2.2 success criteria 1.4.3 (AA, 4.5:1; 3:1 for large text) and 1.4.6 (AAA, 7:1). - Non-text contrast (1.4.11): control borders and icon glyphs at 3:1 — the criterion most checkers skip. - Colours as actually painted: opacity, layered translucent backgrounds, dark mode, text inside shadow DOM components and same-origin frames. What it will not do - Guess. Text over an image or gradient, or under a CSS filter, is listed separately as "check this by eye" and never counted as a failure. - Report screen-reader-only, hidden, disabled or decorative text. - Send anything anywhere. The extension talks to no server; there is no account and no analytics. Free - Five scans a day, the first ten issues in full, and the true total always. - The colour checker, with pick-from-page, unlimited. - Dock the panel beside the page and it stays open while you work. Pro ($19.99 once, bought at auditlint.com; no subscription) - Every issue, unlimited scans. - A fix for each failure: the nearest passing colour in the same hue, ready to paste. - Multi-page reports: each scan joins the current report; export one client-ready document, in HTML that opens cleanly in Word and Google Docs. How it is tested - More than 300 unit tests, and hand-counted fixture pages checked in a real browser on every commit. - The site and the exported report are scanned by the three tools themselves on every commit, and must come back with nothing to report. - Validated against the W3C's ACT rule test cases for text contrast: every official case agrees or is sent to manual review; none disagrees. - Cross-checked against axe-core: nothing axe flags is missing. - A 25,000-element page scans in about a quarter of a second. Made by AuditLint. Also available: Alt Text Auditor and Form & Interactive Auditor, or all three for $39.99.