Color-pair distinguishability API

Checks whether two colors stay distinguishable (LAB ΔE above a threshold) for normal vision AND under protan/deutan/tritan color-blindness, flagging the weakest case so you can add a non-color cue. Answers 'Can color-blind users tell these two colors apart?', 'Is this color pair CVD-safe?'

Price$0.06per request

MethodPOST

Route/v1/design/color-distinguishable

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

accessibilitycolor-blindnesscvddistinguishabledelta-econtrasta11ycolordesign

API URLhttps://x402.hexl.dev/v1/design/color-distinguishable

Integration docs

Example request

{
  "color1": "#ff0000",
  "color2": "#00aa00"
}

Example response

{
  "color1": "#ff0000",
  "color2": "#00aa00",
  "threshold": 10,
  "normalVision": {
    "deltaE": 144,
    "distinguishable": true
  },
  "colorBlind": {
    "protanopia": {
      "deltaE": 49.44,
      "distinguishable": true
    },
    "deuteranopia": {
      "deltaE": 88.36,
      "distinguishable": true
    },
    "tritanopia": {
      "deltaE": 121.17,
      "distinguishable": true
    }
  },
  "safeForAll": true,
  "weakestUnder": "protanopia",
  "interpretation": "Distinguishable for all vision types (min ΔE 49.4 >= 10)."
}

Input schema

{
  "type": "object",
  "required": [
    "color1",
    "color2"
  ],
  "properties": {
    "color1": {
      "type": "string",
      "examples": [
        "#ff0000"
      ]
    },
    "color2": {
      "type": "string",
      "examples": [
        "#00aa00"
      ]
    },
    "threshold": {
      "type": "number",
      "examples": [
        10
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}