Developer
UUID Generator and Formatter
Generate UUID v4 batches or format existing UUIDs as lowercase, uppercase, braced GUIDs, compact IDs, or JSON arrays locally in your browser.
Generate a UUID v4 batch or format existing UUIDs without changing their values. Everything stays in your browser.
Up to 100 IDs per batch. Generation creates v4 only. Formatting accepts hyphenated, compact, braced, or urn:uuid: text and preserves the bits, version, order, and duplicates. It checks text shape, not uniqueness or version semantics. Compact and braced output require destination support.
Reference UUIDs
- Nil UUID:
00000000-0000-0000-0000-000000000000 - Max UUID:
ffffffff-ffff-ffff-ffff-ffffffffffff
0Output IDs
Generate v4Task
100Max batch
How to use UUID Generator and Formatter
Best for
- Creating quick test IDs for fixtures, mock data, and examples.
- Generating a small batch of UUID v4 values without installing a package.
- Formatting existing IDs for JSON fixtures or systems that expect uppercase, braces, or compact text.
- Copying nil and max UUID reference values when documenting ID behavior.
Steps
- Choose Generate UUID v4 or Format existing UUIDs.
- Set a batch count, or paste up to 100 IDs as one per line or a JSON array of strings.
- Generate or format, choose the text format and output layout, then copy the batch.
Notes
- UUIDs are designed to make collisions unlikely, not mathematically impossible.
- Formatting preserves the identifier bits and does not convert v4 to v7, remove duplicates, or prove version semantics. Compact and braced formats are destination-specific.
- Do not use UUIDs as passwords, API keys, session secrets, or security tokens.
FAQ
Can I format existing UUIDs without generating new ones?
Yes. Choose Format existing UUIDs and paste hyphenated, compact, braced, or urn:uuid: values. Output keeps the same IDs and order; choose line-separated text or a JSON array. Invalid entries stop the whole batch.
Does UUID Generator upload generated IDs?
No. UUIDs are generated in your browser and are not sent to a server.
Are UUIDs guaranteed to be unique?
No. UUID v4 values have a very large random space, but uniqueness is still probabilistic.