DT Dev Tools

UUID Generator

Generate UUID v4, v7, v1 and name-based v5/v3 in bulk, then validate and decode any UUID's version and timestamp. Runs entirely in your browser.

πŸ”’ Runs entirely in your browser β€” nothing is uploaded

Validate & decode a UUID

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What UUID Generator does

UUID Generator creates universally unique identifiers in every common flavour defined by RFC 9562. Version 4 is 122 bits of cryptographic randomness and is the default for request IDs, idempotency keys and fixtures. Version 7 puts a 48-bit Unix millisecond timestamp in front of the random bits, so values sort by creation time β€” ideal for database primary keys because inserts stay at the end of B-tree indexes. Version 1 encodes a 100-nanosecond timestamp with a random node ID, and versions 5 and 3 derive a stable UUID from a namespace and a name, so the same URL or DNS name always maps to the same identifier.

You can generate up to 1000 values at once and format them as lowercase or uppercase, with or without hyphens, or wrapped in braces for Windows registry and .NET code. The built-in decoder accepts canonical, braced, URN and 32-digit forms, tells you whether the value is valid, shows the version and variant, and extracts the creation time from v1, v6 and v7 UUIDs β€” handy when you find an ID in a log and want to know when it was minted.

Private browser-based workflow

All processing happens with in-browser JavaScript. The tool does not upload your text, tokens, URLs, snippets, or generated values to a server, and it does not require an account. That privacy model is important because small utilities often receive real API responses, configuration samples, logs, authentication data, or customer-shaped examples during troubleshooting. Keeping the work local reduces risk and also makes the tool feel instant because there is no network round trip.

Practical tips

Random UUID collisions are extraordinarily unlikely for normal development use, but these identifiers are not reserved in a central system, so your application still needs normal uniqueness checks when data is saved. Within one batch, v7 values are strictly increasing even when several are created in the same millisecond. Remember that v1 and v7 reveal when an ID was created; if that leaks business information, prefer v4. Name-based v5 is the better choice over v3 for new code because SHA-1 is stronger than MD5, although neither should be treated as a secret.

How to use

  1. Choose a versionPick v4, v7, v1, or name-based v5/v3 with a namespace and names.
  2. Set count and formatEnter 1 to 1000 UUIDs and choose uppercase, hyphens or braces.
  3. Copy or decodeCopy the list, or paste an existing UUID to validate it and read its timestamp.

Frequently asked questions

Which UUID versions can it generate?
Version 4 (random), version 7 (time-ordered, sortable), version 1 (timestamp + random node), and the name-based versions 5 (SHA-1) and 3 (MD5).
Should I use UUID v4 or v7?
Use v7 for database primary keys: it starts with a millisecond timestamp, so new rows land at the end of the index. Use v4 when the ID must not reveal when it was created.
Can it validate or decode a UUID?
Yes. Paste any UUID into the decoder to see whether it is valid, its version and variant, and the embedded timestamp for v1, v6 and v7.
Are they stored?
No. They are generated locally with the browser's cryptographic random number generator.