- Select UUID v4 (random), UUID v7 (time ordered), or Nil (all zeros)
- Set the quantity of UUIDs to generate (1 to 1000)
- Choose format options: uppercase, remove dashes, or add braces as needed
- Click 'Generate UUID' button to create your UUIDs instantly
- Copy individual UUIDs or all at once, or download as a text file
What is the difference between UUID v4 and UUID v7?
UUID v4 has 122 random bits and reveals no creation time. UUID v7 places a Unix millisecond timestamp first and fills the remaining version-specific fields with random data, which improves approximate chronological ordering. Choose v4 when timestamp disclosure is undesirable; evaluate v7 for write-heavy ordered indexes.
Can generated UUIDs collide?
A collision is possible, not mathematically impossible. Correct UUID v4 generation has a very large 122-bit random space, so accidental collisions remain extremely unlikely at ordinary scale. Systems should still enforce a unique constraint and handle a conflict instead of treating probability as a guarantee.
Should I use UUID v7 as a database primary key?
UUID v7 can improve index locality compared with random UUID v4, but results depend on the database, index, generator behavior, clock ordering, write concurrency, and storage format. Keep a separate authoritative created_at field, benchmark the real workload, and use the database's native 16-byte UUID type where available.
Can a UUID be used as a password, API key, or access token?
No. A UUID does not prove identity or authorization, and timestamp-bearing versions expose metadata. Use a purpose-built token generated from sufficient cryptographic randomness, store and transmit it according to the threat model, and enforce authorization separately.
Does uppercase, braces, or removing dashes change the UUID?
These options change the displayed string only. Uppercase and lowercase hexadecimal represent the same bits, while braces and omitted dashes are alternate textual forms. Confirm that the receiving parser accepts the selected form; the canonical RFC form uses lowercase hexadecimal with hyphens.