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Check that error, success and warning colours stay distinct under colour blindness, with a second cue each

Status colour checkFreeFor designers and developers

25/day

free runs a day, no sign-in.

Before: what you give it

The example input, as typed in. You paste text, CSS, markup or notes.

error: #d32f2f
success: #2e7d32
warning: #ed6c02
info: #0288d1

After: what comes back

The first lines of a real run on that input. Nothing here is edited by hand.

Checked 4 colours, 6 pairs, deltaE (CIE76) under normal vision and simulated protanopia, deuteranopia, tritanopia.
Convention used: under 10 counts as merged, under 20 as weak. Both are working cut-offs, not a standard.

pair                              normal  prot   deut   trit   result
error / success                    102.8   16.9   17.5  113.3   weak under protanopia
error / warning                     35.1   35.6   25.3   17.2   weak under tritanopia
error / info                       109.2   72.2   96.2  120.2   distinguishable
success / warning                     94   19.2   42.8    103   weak under protanopia
success / info                      87.6   83.4   80.4   18.2   weak under tritanopia
warning / info                     124.9  101.2  118.8  107.9   distinguishable

No pair merges at the cut-off.
Weak pairs: error/success; error/warning; success/warning; success/info. They hold in large areas and are risky in small dots, thin lines or chart marks.
... full output on the tool page

What you get

Pair distances under normal vision and three simulated deficiencies, the worst case, and icon and text cues

What it cannot do

Simulates full dichromacy only; the under-10 and under-20 distance cut-offs are working conventions.

Who it is for

  • Designers
  • Developers

Free and Pro

Free25 runs a day per IP address, up to 20,000 characters a run.
ProNo daily limit, 300 requests a minute, up to 200,000 characters a run.

What each plan includes

Use it from your assistant

The tool is called color_meaning_check. Connect the server once, then ask for it by name or just describe the job. Install steps for each app.

claude mcp add --transport http designers https://designers.allthepossibles.com/mcp
curl -X POST https://designers.allthepossibles.com/api/color-meaning-check -H 'content-type: application/json' -d '{"states":"error: #d32f2f\nsuccess: #2e7d32\nwarning: #ed6c02\ninfo: #0288d1"}'

Try it here

The form starts with the same example input, so you can run it first and then swap in your own.

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