Generate UUIDs
Free online UUID generator that runs in your browser. Pick a version (v4 random is the default; v7 if you need sortable IDs; v1 if you need wall-clock time embedded; Nil for sentinels), choose how many you want, pick a format and press Generate. The output is plain text — one UUID per line — copyable individually or all-at-once or downloadable as a .txt file. There is also an inspector that takes any UUID and tells you the version, variant and (for v1/v7) the embedded timestamp decoded to your local time.
How to use
v4 if you do not know — covers 99% of cases.
Choose how many and how they should look.
Copy a single line, copy all, or download as .txt.
Paste an existing UUID to see version, variant, embedded time.
Bulk-generate random or time-ordered UUIDs and inspect existing ones
Inspect a UUID
Features
Typical uses
- Generate a primary key for a database row (v7 is best for indexed inserts).
- Create a session token or correlation ID for tracing.
- Make a unique filename for a generated artifact.
- Inspect a UUID from a log line to see when it was issued (v1/v7).
- Generate test fixtures for unit tests.
Why this one
Most UUID generators give you v4 and stop there. We expose v7 (the modern recommendation for database keys — it sorts by creation time, which keeps B-tree indexes happy) and v1 (still common in older systems with embedded MAC/timestamp), and we let you inspect any UUID to find out what kind it is and when it was made. No signup, no quotas, and the UUIDs themselves are generated by your browser — only anonymous usage telemetry reaches us.
Common questions
Which version should I use?
v4 for general randomness — it is the safe default. v7 if you are using UUIDs as a primary key in an indexed database table, because v7 sorts by time and avoids the random-insert performance penalty v4 has on B-tree indexes. v1 is mostly legacy now (it leaks the MAC address of the machine that generated it). Nil is for sentinel "no UUID yet" cases.
Is window.crypto random enough?
Yes. window.crypto.getRandomValues is a cryptographically secure RNG mandated by the Web Crypto specification. It is the same primitive Node uses for crypto.randomUUID.
Does v7 leak time information?
Yes — that is the point. The first 48 bits are Unix milliseconds. If you do not want the creation time exposed, use v4.
Why is v1 marked legacy?
v1 historically embedded the MAC address of the generating machine, which is a small but real privacy leak. Modern UUIDv1 implementations use a random 48-bit node ID instead, which we also do — but if your project chose v1 for a reason, you should know about the historical concern.
How fast is the generator?
On a 2024 laptop you can generate 10 000 v4 UUIDs in well under a second. The bottleneck is render, not random.
Are these UUIDs unique?
v4 collision probability with 122 bits of entropy is ~1 in 2^61 after a billion UUIDs — practically zero. v7 inherits the same randomness for its last 74 bits, with a time prefix on top.
Mobile?
Yes. Generate, copy, share.
We can — and it's free! Just send us a quick message with your idea. If you'd like to discuss it in detail, leave your email and we'll get back to you. You can stay anonymous.
