UUID / GUID Generator
Generate cryptographically random UUID v4, time-based v1, or Nil UUIDs in bulk. Choose your output format, validate existing UUIDs, and copy — all in your browser, zero server calls.
Generate UUIDs
UUIDs will appear here after you click Generate.
UUID Validator
Paste any UUID to check whether it is properly formatted per RFC 4122.
Free UUID Generator — Bulk, Validated, and Instantly Copyable
A UUID (Universally Unique Identifier) — also called a GUID in Windows/.NET environments — is a standardised 128-bit value defined in RFC 4122. It looks like 550e8400-e29b-41d4-a716-446655440000 and is used everywhere unique, collision-free identifiers are needed: database primary keys, session tokens, file names, request IDs, API keys, and distributed event IDs.
Our generator produces UUID v4 values using crypto.getRandomValues() — the same cryptographic RNG used by browsers for TLS and password managers — so each UUID is genuinely unique. We also support UUID v1 (time-based, useful for sequential indexing) and the Nil UUID (all zeros, a useful sentinel value in specs).
You can generate up to 200 UUIDs in one click, choose from four output formats (standard, uppercase, no hyphens, or braces), copy them one-by-one or all at once, and validate any existing UUID string — all without leaving your browser. Nothing is sent to any server.
How to Use the UUID Generator
- 1
Pick a UUID version
Choose v4 (random) for most use cases, v1 (time-based) if you need sortable/sequential identifiers, or Nil for a zero-value placeholder.
- 2
Set quantity and output format
Enter how many UUIDs you need (up to 200) and select a format: standard lowercase, uppercase, no-hyphens (32-char hex), or curly-brace wrapped (common in .NET GUIDs).
- 3
Click Generate
UUIDs are produced instantly in your browser using the Web Crypto API. No network call is made — results appear in under a millisecond.
- 4
Copy and use
Click "Copy" next to any UUID for single-item copy, or "Copy All" to get all UUIDs as a newline-separated list ready to paste into code, a spreadsheet, or a database seed file.
- 5
Validate an existing UUID (optional)
Paste any UUID string into the validator to instantly check whether it matches the RFC 4122 format. Useful for debugging API inputs or testing UUID columns in your database.
Features
Cryptographically Secure (v4)
UUID v4 is generated via crypto.getRandomValues() — not Math.random() — for true randomness.
Bulk Generation (up to 200)
Generate 1 to 200 UUIDs in a single click. Perfect for seeding test databases or batch imports.
Multiple Versions
v4 (random), v1 (time-seeded), and Nil — all three UUID types supported in one tool.
Output Format Options
Standard, uppercase, no-hyphens (32 hex chars), or brace-wrapped — match your target system's expected format.
Built-in UUID Validator
Paste any UUID string to verify it matches the RFC 4122 pattern. Catches typos and format errors instantly.
One-click Copy
Copy individual UUIDs or all of them at once as a newline-separated list.
100% Client-side
No server. No storage. No telemetry on generated values. UUIDs stay on your device.
Mobile-friendly
Works on any device — iPhone, Android, tablet, or desktop — with no app or plugin needed.
UUID Versions at a Glance
| Version | Generation method | Sortable? | Leaks system info? | Best for |
|---|---|---|---|---|
| v1 | Timestamp + MAC address | Yes (time-ordered) | Yes (MAC address) | Sortable IDs, event logs |
| v4 | Cryptographically random | No | No | Database PKs, API keys, session tokens |
| Nil | All zeros (0x00...) | n/a | No | Sentinel / placeholder value in specs |
Common Use Cases
Database Primary Keys
Use UUID v4 as a primary key in PostgreSQL, MySQL, SQLite, or MongoDB. Avoids integer ID collisions in distributed writes.
REST API Request IDs
Attach a UUID to every API request as a correlation ID for distributed tracing and debugging across microservices.
Session & Auth Tokens
Generate session tokens, CSRF tokens, or one-time link tokens. UUID v4 is unguessable and statistically collision-free.
File & Asset Naming
Rename uploaded files to a UUID before storing in S3 or cloud storage — prevents filename collisions and path traversal attacks.
Test Data & Seed Files
Quickly generate 50–200 UUIDs to populate test databases, fixtures, or CSV seed files for local development.
Webhook & Event IDs
Assign a UUID to each event or webhook payload for idempotency — so receiving systems can deduplicate safely.
Anatomy of a UUID
- xxxxxxxx— 32-bit time_low (in v1) or random bits (in v4)
- xxxx— 16-bit time_mid or random bits
- 4xxx— version nibble (4 = v4 random) + random bits. The leading digit indicates the UUID version.
- yxxx— variant bits (y is always 8, 9, a, or b for RFC 4122) + random bits
- xxxxxxxxxxxx— 48-bit node (MAC address in v1, random bits in v4)
Total: 128 bits = 32 hex characters + 4 hyphens = 36-character string.
Frequently Asked Questions
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