UUID Generator and Validator
Generate, validate and convert UUIDs online: v4, v5, v7, NIL and MAX. Instant and free, in your browser, no upload to any server.
No UUIDs yet. Pick a version above to generate.
What this tool does
Generate, validate and convert UUIDs instantly. Pick a version (v4 random, v5 namespace-based, v7 sortable, NIL or MAX), produce one or many, then copy or download. Everything runs locally in your browser.
For short-lived tokens, pair with Base64 encoder. If you want a URL-friendly version of a UUID, run it through slug generator.
What you can use it for
- Create unique identifiers for database records, with sortable v7 IDs for time-series data.
- Generate deterministic v5 UUIDs from a namespace and a name.
- Validate a UUID coming from logs or an API and detect its version.
- Seed UUID columns in test migrations or fixtures.
How to use it
- Pick the UUID version you need: v4 (random), v5 (deterministic), v7 (sortable), NIL or MAX.
- For v5, choose a namespace and type the name you want to hash.
- Choose how many to generate with the count chips, then copy or download as TXT.
- Switch to Validate to check a UUID and see its detected version.
Everything runs inside your browser. No file is uploaded to any server. See more tools in this field.
When to use UUID v4 and when not to
UUID v4 is the default choice for identifying records, but it's not always the best one. This quick guide helps you decide.
- Primary keys in databasesGood option if you want to generate IDs without coordinating with the database. Watch the index: random UUIDs fragment the index more than autoincrement IDs.
- Session tokensAvoid. For sessions, use signed tokens (JWT) or higher-entropy random bytes. UUID v4 is an identifier, not an authenticator.
- Temporary file namesIdeal. Zero collisions, easy to read in logs, reveals nothing about the contents.
- Event or trace IDsPerfect. Each event carries its own UUID and lets you correlate logs across services.
- Short public URLsBetter not. UUID is long and unreadable. Use nanoid or a short slug if it's meant to be shared.
Pairs well with
Other tools people reach for in the same flow.
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Turn your UUID into a readable slug.
- QR Code Generator (PNG, WiFi)
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- Secure Password Generator
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Frequently asked questions
Which UUID version should I pick?
Use v4 when you just want a random identifier with negligible collision probability. Use v7 when the IDs will be inserted into an index and you care about insertion order. Use v5 when the same input must always map to the same UUID, like deriving an ID from a stable URL or DNS name.
What is UUID v7?
A 128-bit identifier whose first 48 bits encode the Unix timestamp in milliseconds. The rest is random. The practical effect is that v7 UUIDs are lexicographically sortable by creation time, which keeps database indexes much happier than v4.
How is UUID v5 different from v4?
v5 is deterministic. Given the same namespace and the same name, it always returns the same UUID. It is built by hashing the namespace and the name with SHA-1, so you can derive a stable ID from any string.
Is it safe to use UUIDs as tokens?
For opaque identifiers, yes. For session or authentication tokens you should use tokens designed for cryptography (signed tokens, dedicated random bytes). UUIDs are made to identify, not necessarily to authenticate.
Are they generated locally?
Yes. The tool uses your browser's Web Crypto API (crypto.randomUUID, crypto.getRandomValues, crypto.subtle.digest) and runs offline. No UUID ever leaves your device.