UUID Generator
Generate UUID v4 values one at a time or in bulk. Toggle uppercase and dashes, then copy or download your list.
When should you use a UUID v4 instead of a sequential ID?
What this tool does
The Kitnax UUID Generator creates RFC 4122 version 4 identifiers — random 128-bit values formatted as standard UUID strings (also called GUIDs on Microsoft platforms). Generate one ID at a time or produce a bulk list with configurable count, then copy individual values or download the full set as a text file. Toggle uppercase letters and hyphen separators to match your database or API conventions. Generation uses cryptographically secure randomness in your browser; IDs are never logged or sent to Kitnax servers.
Why you need it
Distributed systems need identifiers that multiple services can create independently without colliding. Auto-increment integers require a single database authority; UUID v4 values can be assigned on a mobile client, edge node, or microservice before any central store sees them. That makes UUIDs the default choice for primary keys in prototypes, seed scripts, correlation IDs in logs, and file names in object storage. When you need a batch of unique IDs for test fixtures or migration dry runs, bulk generation with download saves manual copy-paste. UUID and GUID refer to the same concept — GUID is simply Microsoft's name for the same standard.
How to use it
- Click Generate UUID for a single value, or set Count and click Generate Bulk for a list.
- Toggle Uppercase if your style guide requires capital hex digits.
- Enable Remove dashes when your schema stores compact 32-character hex strings.
- Copy All to paste into spreadsheets, SQL seeds, or configuration files.
- Use Download to save the current list as a .txt file for scripts that import IDs in bulk.
Practical examples
- Database seeding: generate fifty UUID v4 primary keys for a staging users table before running integration tests.
- Microservice tracing: assign a fresh correlation ID per inbound HTTP request and propagate it through log lines across services.
- Client-side offline apps: create record IDs on device before sync without waiting for a server sequence.
- Storage keys: use hyphen-free uppercase UUIDs as S3 object key suffixes when your bucket policy expects that format.
How it works
UUID version 4 sets six bits to the version nibble (0100) and two variant bits per RFC 4122; the remaining 122 bits come from a secure random source. Kitnax uses crypto.getRandomValues in the browser — the same class of API production servers use for session tokens. Collision probability is astronomically low for practical volumes: generating billions of v4 UUIDs still leaves collision risk negligible compared to hardware failure or human error.
UUIDs are identifiers, not authentication secrets. Knowing a UUID should not grant access; pair public IDs with proper authorization checks. v4 prioritizes randomness over sort order — if you need time-sortable IDs, consider UUID v7 or ULID elsewhere; this tool focuses on classic v4 random IDs. All generation stays client-side for privacy.
Common mistakes
- Treating UUIDs as unguessable secrets — they are random but often exposed in URLs and logs; never use them alone as bearer tokens.
- Assuming hyphenated and compact forms are different IDs — they encode the same value; pick one format and enforce it in validation.
- Choosing UUIDs for every table without considering index size — at very large scale, sequential keys can be more storage-efficient.
- Expecting sortable insertion order from v4 — random IDs fragment B-tree indexes more than sequential integers.
FAQ
Are these UUID v4?
Yes. Version 4 uses random bits per RFC 4122 with the version and variant fields set correctly. Suitable for primary keys, correlation IDs, and most application identifiers.
Can I generate thousands at once?
Bulk mode supports batches up to the browser count limit shown in the tool. Download as .txt for import scripts or seed files when you need many IDs at once.
UUID vs auto-increment integers?
UUIDs generate offline without a central allocator and merge cleanly across databases. Auto-increment integers are smaller and index faster at extreme scale but require coordination.
Should I remove hyphens?
Some systems store 32-character hex without hyphens. Toggle Remove dashes to match your schema — the underlying randomness is the same.
Are UUIDs secret?
No. UUIDs are public identifiers, not secrets. Do not use them alone as session tokens or authorization credentials.