BuildUtilities
Free Public API

BuildUtilities API

Free REST API for the most common developer tasks. No sign-up, no API key, CORS-enabled.

Quick start

All endpoints live under https://buildutilities.com/api. Methods are GET or POST, all return JSON.

Rate limit: 60 requests / minute / IP, enforced per server instance. Treat it as the ceiling to design against rather than an exact quota, and handle 429 responses.

Auth: none required.

CORS: open to all origins.

Errors: { ok: false, error: "..." } with appropriate HTTP status.

Endpoints

GET/v1/uuid

Generate one or more UUIDs. Query params: ?version=v4|v7 (default v4), ?count=1-100 (default 1).

Request

curl "https://buildutilities.com/api/v1/uuid?count=3&version=v7"

Response

{
  "ok": true,
  "data": ["0192a1b2-c3d4-7890-...", "..."]
}
POST/v1/hash

Hash a string with MD5, SHA-1, SHA-256, or SHA-512.

Request

curl -X POST "https://buildutilities.com/api/v1/hash" \
  -H "Content-Type: application/json" \
  -d '{"input":"hello","algorithm":"sha256"}'

Response

{
  "ok": true,
  "data": "2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824"
}
POST/v1/base64-encode

Base64-encode a string. Optional ?urlSafe=true for URL-safe variant.

Request

curl -X POST "https://buildutilities.com/api/v1/base64-encode" \
  -H "Content-Type: application/json" \
  -d '{"input":"hello"}'

Response

{
  "ok": true,
  "data": "aGVsbG8="
}
POST/v1/base64-decode

Base64-decode a string.

Request

curl -X POST "https://buildutilities.com/api/v1/base64-decode" \
  -H "Content-Type: application/json" \
  -d '{"input":"aGVsbG8="}'

Response

{
  "ok": true,
  "data": "hello"
}
POST/v1/url-encode

Percent-encode a string for use in URLs.

Request

curl -X POST "https://buildutilities.com/api/v1/url-encode" \
  -H "Content-Type: application/json" \
  -d '{"input":"hello world & friends?"}'

Response

{
  "ok": true,
  "data": "hello%20world%20%26%20friends%3F"
}
POST/v1/url-decode

Decode a percent-encoded URL string.

Request

curl -X POST "https://buildutilities.com/api/v1/url-decode" \
  -H "Content-Type: application/json" \
  -d '{"input":"hello%20world"}'

Response

{
  "ok": true,
  "data": "hello world"
}
POST/v1/jwt-decode

Decode a JWT (header + payload only, does NOT verify signature).

Request

curl -X POST "https://buildutilities.com/api/v1/jwt-decode" \
  -H "Content-Type: application/json" \
  -d '{"token":"eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxIn0.xxx"}'

Response

{
  "ok": true,
  "data": {
    "header": { "alg": "HS256" },
    "payload": { "sub": "1" }
  }
}
POST/v1/slug

Convert a string to a URL-safe slug.

Request

curl -X POST "https://buildutilities.com/api/v1/slug" \
  -H "Content-Type: application/json" \
  -d '{"input":"Hello, World! 2026"}'

Response

{
  "ok": true,
  "data": "hello-world-2026"
}
GET/v1/password

Generate a strong password. Query params: ?length=8-128 (default 20), ?symbols=true|false, ?numbers=true|false.

Request

curl "https://buildutilities.com/api/v1/password?length=24&symbols=true"

Response

{
  "ok": true,
  "data": "9K#mT$pL2vQ@wR7nX!hZ4cBk"
}

Using these from an AI coding agent?

There is an MCP server too. It gives Claude, Cursor and anything else speaking the Model Context Protocol direct access to 20 of these utilities — and unlike this API it runs entirely on your own machine, so there is no request, no key and no rate limit.

MCP server setup

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