PRPickrack

UUID Generator

Generate cryptographic UUID v4 — single or up to 1000 in bulk. crypto.randomUUID native.

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Generate cryptographic UUID v4 — single or up to 1000 in bulk. Browser crypto.randomUUID.

UUID Generator produces universally unique identifiers — used for database primary keys, distributed systems, API tracking IDs, and anything needing collision-resistant IDs without coordination.

Pickrack uses the browser's native crypto.randomUUID() — cryptographically random, RFC 4122 v4 compliant, and supported in all modern browsers since 2022. Generate a single UUID or bulk-generate up to 1000 at once for testing fixtures.

Free, no signup, no rate limit. Bulk-copy as a list, or download as .txt. Format: xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx where x is random hex and y is from {8,9,a,b}.

Key features

  • crypto.randomUUID() native — Uses CSPRNG — same entropy source as TLS, SSH. Each UUID has 122 bits of randomness. Collision probability is negligible (1 in 2^122).
  • Single or bulk (1-1000) — Generate one for a config file, or 1000 for a test database fixture. Slider or input for bulk count.
  • Multiple formats — Standard hyphenated (default), uppercase, no-hyphen, braced ({uuid}), as URN (urn:uuid:...). Toggle live.
  • Copy + download — One-click copy of single UUID. Bulk: copy all, or download as .txt for import into databases.
  • Browser-side, no logging — UUIDs are not stored or logged. Each refresh generates fresh values.

How to use

  1. Step 1: Click Generate — Default: 1 UUID. Adjust count slider for bulk.
  2. Step 2: Choose format — Standard UUID is the default; toggle for uppercase, no-hyphens, or other variants.
  3. Step 3: Copy or download — Single UUIDs auto-copy. Bulk: Copy all to clipboard or Download as .txt.

When to use

  • Database primary keys — UUID v4 for distributed systems where you can't coordinate sequential IDs
  • Test fixture data — bulk-generate 100 IDs for inserting into a staging database
  • API request tracking — generate a unique ID per request for log correlation
  • Idempotency keys — for retryable POST requests in payment APIs (Stripe, etc.)
  • Session tokens for non-security identifiers (real session tokens need crypto-strength)
  • File names in S3/GCS to avoid collisions — UUID-prefixed paths

Frequently asked questions

Is crypto.randomUUID secure?

Yes. It uses the same CSPRNG as crypto.getRandomValues — sourced from OS-level entropy (hardware noise, kernel pool). 122 random bits. Collision probability after 1 billion UUIDs is ~10^-18.

What's the difference between v4 and v1/v3/v5?

v4 = random (most common). v1 = timestamp-based (leaks generation time). v3/v5 = namespace-based (deterministic from input). Pickrack outputs v4. For v5/3, use a library like uuid npm package.

Are these UUIDs cryptographically random?

Yes — crypto.randomUUID uses the cryptographic RNG (same as TLS). Pickrack does not generate v4 from Math.random which would be insecure.

Can two people generate the same UUID?

Mathematically possible but astronomically unlikely (~1 in 2^122). Generate 1 billion per second on every device on Earth for a million years; collision still unlikely.

What's the maximum bulk count?

1000 per request, capped to keep UI responsive. For larger batches, use a CLI tool (uuidgen on Linux/Mac, [guid]::NewGuid() PowerShell).

Why are some UUIDs lowercase and some uppercase?

RFC 4122 specifies lowercase. Some legacy systems (especially Windows) use uppercase. Pickrack defaults to lowercase; toggle for uppercase.

Are these compatible with PostgreSQL UUID type?

Yes. Postgres accepts both hyphenated and non-hyphenated formats. Insert directly: INSERT INTO t (id) VALUES ('<uuid>').

Can I generate UUIDs without internet?

Yes once the page is loaded. crypto.randomUUID is built into modern browsers (Chrome 92+, Firefox 95+, Safari 15.4+) and runs purely on local entropy.

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