WCAG Color Contrast Checker

Contrast ratio between two hex colors plus WCAG 2.x AA/AAA pass/fail for normal and large text.

Free tier eligible — 500 calls/month with a free key from /pricing; x402 pay-per-call above quota.

Parameters

Parameter	Type	Required	Description
`foreground`	string	required	Foreground hex color, e.g. '#111111' or '111'
`background`	string	required	Background hex color, e.g. '#FFFFFF' or 'fff'

Call it over MCP (JSON-RPC 2.0)

curl -s https://wingmanprotocol.com/mcp \
  -H 'Content-Type: application/json' \
  -H 'Accept: application/json, text/event-stream' \
  -d '{"jsonrpc": "2.0", "id": 1, "method": "tools/call", "params": {"name": "color_contrast", "arguments": {"foreground": "example", "background": "example"}}}'

Or plain HTTP

curl -s https://wingmanprotocol.com/tools/color_contrast \
  -H 'Content-Type: application/json' \
  -d '{"foreground": "example", "background": "example"}'

Try it live

Edit the JSON and run it — this POSTs to https://wingmanprotocol.com/tools/color_contrast from your browser.

This tool is x402-metered — agents pay per call with USDC on Base. The 402 response below is the standard x402 payment-requirements envelope: sign the EIP-3009 authorization and retry with the X-Payment header, or get a free key at /pricing (500 calls/month, no card, no crypto).