ContrastKit

텍스트와 배경 색상을 WCAG 2.x AA 및 AAA 기준으로 확인하고, 가장 가까운 접근성 색상을 얻고, CSS 색상을 변환하며, 최대 12색의 팔레트 전체를 확인하세요. 무료이며 가입과 API 키가 필요 없고, IP당 분당 약 60회 확인할 수 있습니다. 제출한 내용은 저장되지 않습니다. ContrastKit은 W3C 또는 WebAIM과 제휴 관계가 없습니다.

workers.dev에서 보기

호스팅형 MCP 서버

npx add-mcp 'https://contrastkit.mike-tusa.workers.dev/mcp'

Claude Code, Codex, Cursor 등에 설치됩니다

문서

ContrastKit

Check a text color against its background for WCAG AA and AAA, and get the closest color that passes if it doesn't. Hex, rgb(), hsl() and color names all work. Nothing you type is stored.

How it's measured

Contrast ratio = (L1 + 0.05) / (L2 + 0.05) with WCAG 2.x relative luminance (sRGB). Levels: aa 4.5:1, aa-large 3:1, aaa 7:1, aaa-large 4.5:1, ui 3:1 (aa = SC 1.4.3 normal text, aa-large = 18pt / 14pt bold text, aaa = SC 1.4.6, ui = SC 1.4.11 non-text). Ratios are floored to 2 decimals and pass/fail uses the exact value, so 4.499:1 fails AA. A translucent foreground is blended over the background; a translucent background is blended over white. See WCAG 2.2 success criterion 1.4.3.

Colors: #rgb, #rgba, #rrggbb, #rrggbbaa (the # may be omitted; URL-encode it as %23), rgb()/rgba() and hsl()/hsla() in comma or space syntax with optional alpha (0-1 or %), the 148 CSS color names and transparent. Max 64 characters per color. Not supported: lab(), lch(), oklch(), color(), currentColor, system colors.

JSON API

curl -s 'https://contrastkit.mike-tusa.workers.dev/api/contrast?fg=%23777777&bg=%23ffffff'
curl -s 'https://contrastkit.mike-tusa.workers.dev/api/suggest?fg=%23777777&bg=%23ffffff&level=aa'

Routes: /api/contrast, /api/suggest, /api/convert and /api/palette (up to 12 colors). No key needed: about 60 requests per minute per IP. OpenAPI 3.1 spec

For AI agents

ContrastKit is also a remote Model Context Protocol (MCP) server with four read-only tools: check_contrast, suggest_accessible_color, convert_color and check_palette. Works with AI agents and assistants that can call an MCP server or a JSON API, for example Muse, Claude, ChatGPT or Cursor (descriptive only). Most MCP clients accept this config; some use a different format (for example, VS Code uses a servers key).

{ "mcpServers": { "contrastkit": { "type": "http", "url": "https://contrastkit.mike-tusa.workers.dev/mcp" } } }

Machine-readable docs: llms.txt · OpenAPI 3.1 spec · MCP server card. ContrastKit is not affiliated with, endorsed by or sponsored by the W3C, WebAIM, Meta, Anthropic, OpenAI or Anysphere. WCAG is a W3C standard; a passing ratio is one part of accessibility, not a full audit.