UUID Generator

What this UUID generator does

This English-language UUID generator creates RFC 4122-compliant version 4 identifiers using crypto.getRandomValues — the same Web Crypto primitive that browsers expose for cryptographic work. Each UUID carries 122 bits of randomness, which works out to roughly 5.3 × 10^36 unique values: the probability of a collision across a trillion generated IDs is astronomically small. Because all generation happens locally, 100% client-side — your data never leaves your browser. No uploads, no tracking, no server logs. You can produce a single UUID or batch up to 1,000 at once, then copy them to your clipboard or download a plain-text file. Optional uppercase and without-dashes variants let you match whatever format your database or API expects. If you also need to encode identifiers for safe transport, the [Base64 encoder & decoder](/en/base64/) handles that without leaving your machine either.

Features

• Cryptographically secure entropy. Uses crypto.getRandomValues rather than Math.random(), so each UUID meets the unpredictability bar required for security-sensitive identifiers like session tokens and idempotency keys.
• Bulk generation up to 1,000. Need a full set of test fixtures or pre-seeded database rows? Generate up to 1,000 UUIDs in a single click and download them as a .txt file.
• Uppercase and no-dash variants. Toggle uppercase for systems that store IDs in CHAR(36) columns expecting capital hex, or strip dashes to get the compact 32-character form — useful for URL slugs or some NoSQL key schemes.
• One-click copy. Copy all generated UUIDs to your clipboard instantly. The button label updates to "Copied!" so you always know the operation succeeded.
• Zero dependencies, fully offline. There is no npm package, no CDN call, and no backend. The tool works on an airplane or in an air-gapped environment — anywhere a modern browser runs.

How to use the UUID generator

Set a count, pick your format options, hit Generate, then copy or download. You can also generate a random UUID programmatically with crypto.randomUUID() in JavaScript, import uuid; uuid.uuid4() in Python, or uuidgen in a Unix shell.

1. Set the count. Enter a number between 1 and 1,000 in the Count field. The default is 1.
2. Choose format options. Check Uppercase if your system expects capital letters. Check Without dashes for the 32-character hex form with no hyphens.
3. Click Generate. The list of UUIDs appears immediately. Each one follows the standard 8-4-4-4-12 format unless you chose the no-dash variant.
4. Copy or download. Click Copy all to send the full list to your clipboard, or Download .txt to save a newline-delimited file for later use.

Common use cases

• Idempotency keys for HTTP requests. Payment processors and job queues use a unique key per request so that retries don't double-charge or re-enqueue. Generate one UUID per call and attach it as a header.
• Distributed primary keys. In microservice architectures spread across multiple data centers — say, one in New York and one on the West Coast — auto-increment integers require coordination. A UUID v4 is assigned client-side with no central counter.
• Trace and correlation IDs. Assign a UUID at the edge of a request and propagate it through every downstream service log. When something breaks, grep for that one ID across your entire observability stack.
• Test fixture seeds. Pre-generate a batch of UUIDs for unit tests or database migrations so your fixtures have stable, realistic-looking IDs. Pair with the [URL encoder & decoder](/en/url-encoder/) if those IDs appear in query strings.
• Ephemeral session tokens. For low-stakes sessions — demo environments, short-lived preview links — a UUID v4 provides enough entropy to be unguessable without standing up a dedicated token service.

Frequently asked questions