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Color contrast matrix

Paste a list of hex colors. See WCAG 2.1 contrast ratios for every pair. Local math.

No uploads. No account. Free to use.

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Under the Hood: The Architecture of Color contrast matrix

Design tokens are not secret, but a local matrix is faster than N plugin round-trips.

Contrast matrix computes relative luminance and the WCAG ratio for each unordered pair. There is no origin fetch and no upload route. Inputs are strings, JSON, or File objects decoded with the platform APIs in this tab.

Memory Allocation & Browser Threading Mechanics

Work stays on the main thread because typical pastes are kilobytes, not gigabytes. useMemo or an explicit button recomputes a derived string. Image tools downsample onto a canvas so pixel loops stay bounded. Crypto uses SubtleCrypto, which returns ArrayBuffers the engine can recycle after you copy the result.

Algorithmic Deep-Dive: Code Snippet & Logical Analysis

ratio = (L1 + 0.05) / (L2 + 0.05); // WCAG 2 relative luminance

Treat the snippet as the contract: deterministic in, deterministic out. Invalid input should surface a string error, not a thrown render.

The Local Storage Sandbox & Volatile Data Pipelines

Default is React state only. Object URLs from canvases or downloads are revoked after click when the island uses URL.createObjectURL. There is no “recent jobs” IndexedDB. Close the tab to drop secrets (JWT HMAC keys, TOTP seeds, VAPID private JWK).

Verifying True Privacy: How to Audit Your Browser's Network Tab

F12 → Network → clear. Run the tool with a canary string such as TWA_CANARY_TOKEN. Filter Fetch/XHR. The canary must not appear in any request payload. Ads and analytics on the shell are unrelated to the island; they must not receive File bytes.

  • Files never leave your device
  • Runs entirely in your browser
  • No signup required
  • Free

What is Color contrast matrix?

Contrast matrix computes relative luminance and the WCAG ratio for each unordered pair.

How to use it

  1. Paste hex colors.
  2. Read the matrix.
  3. Keep pairs that pass AA or AAA.

When to use it

Design tokens are not secret, but a local matrix is faster than N plugin round-trips.

Frequently asked questions

Are my files uploaded?

No. This tool runs in your browser. Files and text stay on your device and are not sent to our servers.

Does this use AI?

No. It is a deterministic utility. There is no model and no third-party processing of your data.

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