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UUID / ULID / NanoID Generator

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Online batch generator for UUID v4, ULID, NanoID and random hex IDs, using cryptographically secure randomness.

How to Use & FAQ5 steps · 8 Q&A

UUID / ULID / NanoID Generator

Online batch generator for UUID v4, ULID, NanoID and random hex IDs, using cryptographically secure randomness.

How to Use

  1. Choose a typeUUID v4 (general), ULID (sortable), NanoID (short) or random hex — pick by scenario.
  2. Set count and formatEnter the count and, per type, choose uppercase, no hyphens, etc.
  3. Click "Generate"Results are listed for one-click copy and generated entirely locally, with no upload.
  4. Check uniquenessAfter generating, de-duplicate if used in critical contexts; batch to avoid missing any.
  5. Use it in your projectUse the generated ID as a resource identifier or file name; do not embed sensitive info in public IDs.

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Related reading

API Idempotency, Retries and Timeouts: Making Failure PredictableWhich UUID Version? v1, v4, v7 and When Not to Use OneUUIDs and Random IDs: Can They Be Primary Keys

FAQ

What is the difference between UUID v4 and ULID?

UUID v4 is fully random (128 bits). ULID has a 48-bit timestamp prefix and 80 random bits, so lexicographic order roughly reflects creation order, and it is shorter and more readable. ULID is handier when you need time-ordered IDs.

Can generated IDs collide?

They are generated with cryptographically secure randomness and a high number of random bits, so the collision probability is extremely low (far below being hit by a meteor). But in distributed systems, still keep a unique constraint as a safety net.

What are the advantages of NanoID?

NanoID is shorter and URL-friendly, making it great as a front-end short ID or a short code in links; it defaults to 21 characters with sufficient randomness and customizable alphabet/length.

Can the hyphens in a UUID be removed?

Yes. Removing hyphens still represents the same ID in hex, useful for compact storage or format-sensitive fields; restore the 8-4-4-4-12 layout when displaying.

Is there a limit on batch generation?

Generation is instantaneous and local, so you can produce many at once; for very large counts, generate in batches so copying and checking stay manageable and the clipboard is not overwhelmed.

Are these IDs suitable as database primary keys?

All are usable. ULID has a timestamp prefix and is roughly ordered, helping indexing and range queries; UUID v4 is fully random and spreads writes (avoiding hot spots) but may cause random clustering; NanoID is shorter for length-sensitive cases.

Can these IDs be used as keys or tokens?

They work as opaque identifiers (resource IDs, file names) but not as secrets. UUID / ULID / NanoID are publicly predictable random values and cannot replace keys, session tokens or CSRF tokens, which need higher strength and must stay secret.

Why do I sometimes see UUID v1 instead of v4?

v1 encodes a MAC address and timestamp, so it is sortable but may leak machine info; v4 is fully random and more private. This tool generates the more privacy-friendly v4 by default; consider timestamped ULID only when ordering matters.