UUID Generator
Generate random v4 UUIDs in bulk
🔒 100% free · no signup · files never leave your device
A UUID (universally unique identifier) is a 128-bit value formatted as 8-4-4-4-12 hexadecimal groups, like 3f2504e0-4f89-41d3-9a0c-0305e82c3301. Version 4 UUIDs are built from 122 random bits, giving roughly 5.3×10³⁶ possible values — the probability of a collision stays negligible even after generating billions of IDs. That's the entire point: systems can mint identifiers independently, on any machine, with no central registry or coordination, and merge them later without conflicts.
This free UUID generator produces standards-compliant v4 UUIDs via crypto.randomUUID(), the browser's cryptographically secure RNG following RFC 4122. Generate one at a time or in bulk for seed data, then copy individual values or the whole list with one click. It runs fully offline in your browser — no server, no logs, no rate limits. Ideal for primary keys in distributed databases, idempotency tokens, file naming, test fixtures and anywhere two systems must assign IDs that can never collide.
Why use UUID Generator
Database primary keys
UUID keys let sharded and multi-writer databases insert rows without coordinating sequences — standard practice in distributed systems.
Seeding test fixtures
Bulk-generate a hundred IDs at once to populate development databases, mocks and API test payloads.
Idempotency keys for API requests
Attaching a fresh UUID per operation lets servers safely deduplicate retried payments and form submissions.
Collision-proof file and asset names
Naming uploads with UUIDs prevents overwrites and removes the privacy issue of sequential, guessable URLs.
Pro tips
- v4 (random) is the right default; only reach for v1/v7 (time-based) when you specifically need sortable, roughly chronological IDs.
- Store UUIDs in a native uuid column type (Postgres) or binary form — 128-bit binary indexes far better than 36-character text.
- Never derive security from UUID secrecy alone: 'unguessable' IDs are not authorization — still check permissions on requests.
- The hyphens are just formatting; comparisons should normalize case and format, since some systems emit uppercase or hyphenless variants.
How to use UUID Generator
- 1Choose how many UUIDs you need
- 2Click Generate
- 3Copy individual UUIDs or the whole list
Frequently Asked Questions
What UUID version is generated?▾
Version 4 (random), generated with crypto.randomUUID() following RFC 4122.
Can UUIDs collide?▾
Practically no — the chance of a duplicate v4 UUID is about 1 in 5.3×10³⁶ for billions of IDs.