Free tools, Developers
UUID generator
Generate one or many UUIDs, pick the format and copy. Paste a UUID below to see its version and timestamp.
Questions
v4 or v7: which UUID should I use?
v7 for database primary keys: it starts with a timestamp, so new rows are stored in order and indexes stay fast. v4 is fully random and fine for everything else, like file names, tokens and request IDs.
Can two UUIDs ever be the same?
In practice, no. A v4 UUID has 122 random bits. You would need to generate about a billion per second for 85 years to have a 50% chance of a single duplicate.
Are these UUIDs random enough for security?
They come from your browser’s cryptographic random generator. Even so, don’t use a UUID as the only secret for anything important; use a proper token designed for that.
More developers tools
- JSON formatterFormat, validate and minify JSON, with the exact error position.
- Base64 encoderEncode and decode Base64 text, or turn a file into a data URI.
- URL encoderEncode and decode URL components and break a URL into parts.
- JWT decoderRead the header and payload of a JSON Web Token and its expiry.
- Regex testerTest regular expressions with live highlighting and groups.
- Cron expression helperExplains a cron schedule in plain English and shows the next runs.