Convertitive API

Free JSON conversion API · CORS-enabled · No API key

Every Convertitive conversion is also exposed as a JSON HTTP endpoint under /api/v1/. No signup, no API key, no rate limit beyond Cloudflare’s default DDoS protection. Suitable for ad-hoc scripts, dashboards, and low-volume product integrations.

Quick start

curl 'https://convertitive.com/api/v1/convert/unit?category=length&from=cm&to=inches&value=5'

All endpoints return a JSON envelope with ok: true on success and a structured error object (with code field) on failure.

Endpoints

GET/api/v1/categories

List every unit category and its units.

Request

curl https://convertitive.com/api/v1/categories

Response

{
  "ok": true,
  "data": [
    {
      "id": "length",
      "name": "Length",
      "baseUnit": "m",
      "unitCount": 12,
      "units": [
        { "id": "cm", "name": "centimeter", "symbol": "cm", ... },
        ...
      ]
    },
    ...
  ]
}

GET/api/v1/categories/{id}

Full details of a single category, including intro prose and every unit.

Request

curl https://convertitive.com/api/v1/categories/length

Response

{ "ok": true, "data": { "id": "length", "name": "Length", "intro": "...", "units": [...] } }

GET/api/v1/convert/unit

Convert between two units within the same category. Required params: category, from, to, value.

Request

curl 'https://convertitive.com/api/v1/convert/unit?category=length&from=cm&to=inches&value=5'

Response

{
  "ok": true,
  "data": {
    "from": { "id": "cm", "symbol": "cm", "name": "centimeter" },
    "to":   { "id": "inches", "symbol": "in", "name": "inch" },
    "value": 5,
    "result": 1.9685039370078738
  },
  "meta": { "category": "length", "factor": 0.39370078740157477 }
}

GET/api/v1/convert/base

Convert an integer between number bases (binary / octal / decimal / hexadecimal). BigInt under the hood; any size works.

Request

curl 'https://convertitive.com/api/v1/convert/base?from=decimal&to=hexadecimal&value=255'

Response

{ "ok": true, "data": { "from": { "id": "decimal", "radix": 10 }, "to": { "id": "hexadecimal", "radix": 16 }, "value": "255", "result": "FF" } }

GET/api/v1/convert/color

Convert between HEX, RGB, HSL, and HSV. Returns the formatted output string and the canonical sRGB triple.

Request

curl 'https://convertitive.com/api/v1/convert/color?from=hex&to=rgb&value=%23FF6B35'

Response

{ "ok": true, "data": { "from": { "id": "hex", "name": "HEX" }, "to": { "id": "rgb", "name": "RGB" }, "value": "#FF6B35", "result": "rgb(255, 107, 53)", "rgb": { "r": 255, "g": 107, "b": 53 } } }

GET/api/v1/convert/currency

Convert between currencies at the latest ECB mid-market rate. Cached for 1 hour.

Request

curl 'https://convertitive.com/api/v1/convert/currency?from=USD&to=EUR&value=100'

Response

{ "ok": true, "data": { "from": { "code": "USD", "name": "US Dollar" }, "to": { "code": "EUR", "name": "Euro" }, "value": 100, "result": 92.5 }, "meta": { "rate": 0.925, "rateDate": "2026-05-12", "source": "European Central Bank via Frankfurter" } }

GET/api/v1/currency/rates

Latest FX rate snapshot — full rate table relative to the base currency.

Request

curl https://convertitive.com/api/v1/currency/rates

Response

{ "ok": true, "data": { "base": "EUR", "date": "2026-05-12", "rates": { "USD": 1.08, "GBP": 0.85, ... } } }

GET/api/v1/health

Liveness probe. Returns 200 with uptime in seconds.

Request

curl https://convertitive.com/api/v1/health

Response

{ "ok": true, "data": { "service": "convertitive-api", "version": "v1", "uptime": 12345.6 } }

Error format

When a request fails, the response sets ok: false and returns a structured error.

{
  "ok": false,
  "error": "Unknown unit 'cmm' in category 'length'",
  "code": "UNKNOWN_UNIT"
}

Possible codes:

BAD_REQUEST — missing or malformed query parameter
INVALID_VALUE — value out of range or unparseable
UNKNOWN_CATEGORY — category id not recognised
UNKNOWN_UNIT — unit id not present in the specified category
UNKNOWN_BASE — base id not in (binary | octal | decimal | hexadecimal)
UNKNOWN_FORMAT — color format id not in (hex | rgb | hsl | hsv)
UNKNOWN_CURRENCY — ISO 4217 code not supported

CORS & caching

All endpoints set Access-Control-Allow-Origin: * — you can call them from any browser origin. The deterministic endpoints (unit / base / color) carry a one-day cache header; currency endpoints carry a one-hour cache header matching the upstream rate refresh.

Fair use

The API is intentionally free and unauthenticated. Cloudflare in front of the origin will rate-limit obvious scraping. For high-volume integrations (above a few thousand requests per day), please host your own copy — the Convertitive source is available on GitHub.