UUID Generator Online (v1, v4, v5) — Free
Runs 100% in your browser — your files never leave your device.
Database keys, trace IDs, idempotency tokens — UUIDs are everywhere. Generate time-based v1, random v4, or deterministic v5 identifiers, with the standard DNS, URL, OID, and X500 namespaces available for v5 hashing. Everything is produced locally with your browser's random source.
How it works
- 1
Choose a version
Pick v1 (time-based), v4 (random), or v5 (name-hashed).
- 2
Add name and namespace for v5
Deterministic v5 UUIDs hash a name inside a namespace like DNS or URL.
- 3
Generate and copy
One click mints the identifier; another copies it.
About this tool
What makes a UUID useful
A UUID is a 128-bit identifier designed to be unique across every machine and every moment — generate two anywhere and they collide with probability so small it never happens in practice. That is why they are the standard identifier for database rows, distributed systems, and anything that cannot coordinate a counter.
The versions and their trade-offs
Version 4 (random) is the default and reveals nothing — but its randomness makes database indexes scatter. Versions 1 and 7 embed time, so they sort chronologically and index friendlier; v1 uses hardware MAC, v7 uses modern random with a time prefix. Pick v4 for anonymity, v7 for ordered identifiers.
Generate as many as you need
Batch-generate UUIDs with one click, each independently random. They are plain strings — paste them anywhere an identifier goes: URLs, JSON, database rows, log lines.
Frequently asked questions
Can two UUIDs ever collide?
Practically no — v4 offers 122 random bits; generating a billion UUIDs a second for a century would still leave collision odds negligible. Coordination-free uniqueness is the entire design.
Which version should I use for database keys?
v4 if index scatter does not concern you, v7 if you want time-ordered identifiers that keep database indexes compact. Avoid v1 unless you need hardware-derived uniqueness.
Are UUIDs safe to expose in URLs?
v4 UUIDs reveal nothing, so they work as public identifiers — but they are not secrets and not access control. Anything gated by a UUID alone is gated by obscurity.