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Stop Using Math.random() for IDs — Free UUID v4/v7, ULID & NanoID Generator API

#webdev #javascript #tutorial #api

Every developer has been there: you need a unique identifier for a database row, a session token, or a distributed system event — and you reach for Math.random(). Don't. Math.random() is not cryptographically secure, collisions are possible, and it gives you no useful metadata.

This post walks you through a free UUID Generator API hosted on Cloudflare Workers that supports UUID v4, UUID v7 (time-ordered), ULID, NanoID, and custom ID formats — all in a single REST API, no API key required.

RapidAPI listing: UUID Generator API on RapidAPI

Why UUID v4 Is Not Always the Right Choice

UUID v4 is universally unique and random — perfect for most cases. But once you need to sort records by creation time or debug distributed systems, random IDs become painful. You can't tell which event happened first from a2f3c1d4-... vs b8e7f923-....

That's where UUID v7 and ULID come in:

Format Sortable? Random bits Use case
UUID v4 No 122 bits General purpose
UUID v7 Yes (time-prefix) 74 bits Databases, event logs
ULID Yes (ms precision) 80 bits High-throughput systems
NanoID No Variable Short URLs, tokens

Getting Started — No API Key Needed

Base URL:

https://uuid-generator-api.miccho27-5ojagggbio.workers.dev
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Or via RapidAPI (recommended for production — rate limits included):

https://uuid-generator-api.p.rapidapi.com
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Generate UUID v4

The classic. Cryptographically random, globally unique.

curl:

curl "https://uuid-generator-api.p.rapidapi.com/v4" \
  -H "X-RapidAPI-Key: YOUR_KEY" \
  -H "X-RapidAPI-Host: uuid-generator-api.p.rapidapi.com"
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JavaScript (fetch):

const response = await fetch(
  "https://uuid-generator-api.p.rapidapi.com/v4",
  {
    headers: {
      "X-RapidAPI-Key": "YOUR_RAPIDAPI_KEY",
      "X-RapidAPI-Host": "uuid-generator-api.p.rapidapi.com",
    },
  }
);
const data = await response.json();
console.log(data.uuid);
// "550e8400-e29b-41d4-a716-446655440000"
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Response:

{
  "uuid": "a2f3c1d4-8b7e-4f92-b3c1-9d2e4f8a6b5c",
  "version": 4,
  "timestamp": "2026-04-02T10:15:30.000Z"
}
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Generate UUID v7 — Time-Ordered IDs

UUID v7 (RFC 9562) embeds a millisecond timestamp in the first 48 bits. This means IDs generated later will always sort after earlier ones — perfect for database primary keys.

const response = await fetch(
  "https://uuid-generator-api.p.rapidapi.com/v7",
  {
    headers: {
      "X-RapidAPI-Key": "YOUR_RAPIDAPI_KEY",
      "X-RapidAPI-Host": "uuid-generator-api.p.rapidapi.com",
    },
  }
);
const data = await response.json();
console.log(data.uuid);
// "01956ca4-8f20-7a3b-bc1e-9f2e4f8a6b5c"
// ^ first 8 chars encode the timestamp
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In PostgreSQL, this lets you skip a separate created_at column for ordering:

SELECT * FROM events ORDER BY id; -- works correctly with UUID v7
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Generate ULID — Lexicographically Sortable

ULID (Universally Unique Lexicographically Sortable Identifier) is a 26-character string that sorts correctly as a plain string — great for systems that don't support UUID natively.

curl "https://uuid-generator-api.p.rapidapi.com/ulid" \
  -H "X-RapidAPI-Key: YOUR_KEY" \
  -H "X-RapidAPI-Host: uuid-generator-api.p.rapidapi.com"
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Response:

{
  "ulid": "01HVMK3RZQFP4NTBTK7JMWC9Z0",
  "timestamp": "2026-04-02T10:15:30.000Z"
}
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The first 10 characters encode the timestamp — so "01HVMK3..." < "01HVMK4..." is chronological.

Generate NanoID — Short and URL-Safe

NanoID is a compact, URL-safe alternative to UUID. The default size is 21 characters, but you can customize it.

// Default size (21 chars)
const r1 = await fetch("https://uuid-generator-api.p.rapidapi.com/nanoid", {
  headers: { "X-RapidAPI-Key": "YOUR_KEY", "X-RapidAPI-Host": "uuid-generator-api.p.rapidapi.com" }
});

// Custom size (10 chars for short URLs)
const r2 = await fetch("https://uuid-generator-api.p.rapidapi.com/nanoid?size=10", {
  headers: { "X-RapidAPI-Key": "YOUR_KEY", "X-RapidAPI-Host": "uuid-generator-api.p.rapidapi.com" }
});

const short = await r2.json();
console.log(short.nanoid); // "V1StGXR8_Z"
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Bulk Generation — Up to 1000 IDs at Once

Need to seed a database or generate test fixtures? Use the /bulk endpoint.

const response = await fetch(
  "https://uuid-generator-api.p.rapidapi.com/bulk?type=v4&count=5",
  {
    headers: {
      "X-RapidAPI-Key": "YOUR_KEY",
      "X-RapidAPI-Host": "uuid-generator-api.p.rapidapi.com",
    },
  }
);
const data = await response.json();
console.log(data.ids);
// ["3f2504e0-...", "6ba7b810-...", "6ba7b811-...", "6ba7b812-...", "6ba7b813-..."]
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Supported types: v4, v7, ulid, nanoid. Max count: 1000.

Custom IDs — Prefixed and Charset-Controlled

Need usr_abc123 style IDs for your SaaS app? The /custom POST endpoint has you covered.

const response = await fetch(
  "https://uuid-generator-api.p.rapidapi.com/custom",
  {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "X-RapidAPI-Key": "YOUR_KEY",
      "X-RapidAPI-Host": "uuid-generator-api.p.rapidapi.com",
    },
    body: JSON.stringify({
      prefix: "usr",
      separator: "_",
      length: 12,
      charset: "alphanumeric",
      count: 3,
    }),
  }
);
const data = await response.json();
console.log(data.ids);
// ["usr_aB3xK9mP2qRt", "usr_7fGhJ4nV1wZs", "usr_cDeLo5pQ8yUv"]
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Available charsets: alphanumeric, numeric, hex, lowercase, uppercase.

UUID Validation

Paste in any UUID string to check if it's valid and detect its version.

const uuid = "550e8400-e29b-41d4-a716-446655440000";
const response = await fetch(
  `https://uuid-generator-api.p.rapidapi.com/validate?uuid=${uuid}`,
  {
    headers: {
      "X-RapidAPI-Key": "YOUR_KEY",
      "X-RapidAPI-Host": "uuid-generator-api.p.rapidapi.com",
    },
  }
);
const data = await response.json();
console.log(data);
// { uuid: "550e8400-...", valid: true, version: 4 }
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Real-World Integration Pattern

Here's a pattern for generating IDs on the server side via an API call, useful when your runtime doesn't have a native UUID implementation (e.g., some edge environments):

// id-service.js
const RAPIDAPI_KEY = process.env.RAPIDAPI_KEY;
const BASE_URL = "https://uuid-generator-api.p.rapidapi.com";
const HEADERS = {
  "X-RapidAPI-Key": RAPIDAPI_KEY,
  "X-RapidAPI-Host": "uuid-generator-api.p.rapidapi.com",
};

export async function generateId(type = "v7") {
  const res = await fetch(`${BASE_URL}/${type}`, { headers: HEADERS });
  if (!res.ok) throw new Error(`ID generation failed: ${res.status}`);
  const data = await res.json();
  return data.uuid || data.ulid || data.nanoid;
}

export async function generateBulkIds(count = 100, type = "v4") {
  const res = await fetch(
    `${BASE_URL}/bulk?type=${type}&count=${count}`,
    { headers: HEADERS }
  );
  const data = await res.json();
  return data.ids;
}

// Usage
const sessionId = await generateId("nanoid");    // short URL-safe token
const recordId  = await generateId("v7");        // sortable DB primary key
const testIds   = await generateBulkIds(50, "v4"); // test fixture data
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Summary

Endpoint Method Returns
/v4 GET UUID v4
/v7 GET UUID v7 (time-ordered)
/ulid GET ULID
/nanoid?size=N GET NanoID
/bulk?type=X&count=N GET Array of IDs
/custom POST Prefixed custom IDs
/validate?uuid=X GET Validation result

Free tier: 100 requests/day. Upgrade on RapidAPI for higher limits.

If you found this useful, check out the full collection of 40+ free APIs I've built on Cloudflare Workers — all with free tiers, no credit card required.

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