UUID Generator

Free UUID generator tool. Instantly generate a single RFC 4122 v4 UUID, bulk generate up to 1000 at once, or validate any UUID string in seconds.

More free online data tools — no install required.

What UUID Generator Does

Takes no input for single generation and outputs one RFC 4122 v4 UUID in standard hyphenated format. In bulk mode, takes a number between 1 and 1000 and outputs that many UUIDs each on its own line. In validate mode, takes one or more UUIDs — one per line — and outputs a per-line VALID or INVALID verdict alongside a total count of valid and invalid entries.

Who Uses This Tool

UUID Generator is built for Backend developers seeding database primary keys, frontend developers generating temporary component keys, DevOps engineers producing unique deployment identifiers, QA engineers populating test fixtures with unique IDs, database architects designing distributed systems, API developers generating request correlation IDs. Whether you are processing data as part of an automated pipeline or need a quick one-off conversion in your browser, the tool requires no installation and no account — paste your input and get your result in seconds.

Primary Use Case

Generating a single cryptographically secure UUID v4 to use immediately as a unique identifier in a database record, API payload, or configuration file.

The Problem It Solves

Generating UUIDs programmatically requires importing a library or writing crypto-based generation code just to get a single identifier during development or testing. Validating externally received UUIDs for RFC 4122 v4 compliance by eye is unreliable — the version bit and variant bit constraints in positions 13 and 17 are invisible without a regex check. This tool provides instant generation and multi-line batch validation without any setup, dependency, or server round-trip.

Example

Input
7
Output
f014f4b9-3f00-4786-924c-78b2e12779f8
32de8719-1664-4a1d-8d1a-6c2d58e325f5
da59682c-2164-4222-ade1-0db25daf155e
71b2d204-b465-4729-bce4-045e617e6e82
7283a887-ba36-48e0-b15d-38dcaa74bd76
8a54a4cf-311f-4b7b-b9e9-e1e45696ee4d
0bc6ed2e-e91c-4092-b4dc-80fca4b3ed94

When to Use This Tool

Use this tool when generating database identifiers, API tokens, session IDs, distributed system identifiers, or unique object references that require low collision probability.

What to Do With the Output

Paste single UUIDs directly into database insert statements, API request bodies, or config files as unique identifiers. Copy bulk output into seed scripts, test fixture files, or spreadsheets. Use validation output to gate UUID acceptance in data pipelines or log audits before processing externally sourced identifiers.

Common Mistakes to Avoid

Bulk mode defaults to 10 UUIDs if the input field is empty or contains a non-numeric value — entering text instead of a number will not throw an error but will silently generate 10. The maximum bulk limit is 1000; requesting more returns an error. Validate mode checks strictly against the RFC 4122 v4 pattern — UUIDs from other versions (v1, v3, v5) will be flagged as invalid since they do not have 4 as the version digit or the correct variant bits. Blank lines in validate input are silently skipped and do not count toward the invalid total.

How It Works

The generator fills a 16-byte Uint8Array using crypto.getRandomValues(), which sources entropy from the operating system's cryptographically secure random number generator. Two bytes are then masked to enforce RFC 4122 v4 compliance: byte 6 is masked with 0x0f and OR'd with 0x40 to set the version to 4, and byte 8 is masked with 0x3f and OR'd with 0x80 to set the variant bits to 10xx. The 16 bytes are converted to lowercase hex pairs and assembled into the standard 8-4-4-4-12 hyphenated format. Validation tests each input line against a strict regex requiring the version digit 4 at position 13 and a variant character of 8, 9, a, or b at position 17.

Pro Tip

When seeding a test database with relational records, use bulk mode to generate matching counts for each table in one session — generate 50 UUIDs for users, copy them, generate 50 more for orders — then reference them cross-table in your seed scripts, guaranteeing no collisions without running any code locally.

Also Known As

UUID Generator is also commonly referred to as UUID generator online, random UUID, GUID generator, generate GUID online, UUID v4 online, unique ID generator, RFC 4122 UUID, bulk UUID generator, UUID checker, UUID format validator. All of these terms describe the same conversion — no matter what you call it, this tool handles it.

Frequently Asked Questions

They refer to the same format. GUID is Microsoft's terminology for the same 128-bit identifier standard defined in RFC 4122. UUIDs generated by this tool are structurally identical to GUIDs and compatible with any system that accepts either term.
UUID v4 uses 122 bits of cryptographic randomness, producing approximately 5.3 undecillion possible values. The probability of a collision across any realistic generation volume is negligibly small for all practical purposes.
The validator checks strictly for RFC 4122 v4 format — the digit at position 13 must be 4 and the character at position 17 must be 8, 9, a, or b. UUIDs from other versions or with incorrect variant bits will fail even if the overall format looks correct.
Bulk mode supports a maximum of 1000 UUIDs per generation. Entering a value above 1000 returns an error. Entering a non-numeric value silently defaults to generating 10.
No. All generation happens entirely in the browser using the native Web Crypto API. No UUIDs are transmitted to or stored on any server.
Yes. Paste one UUID per line into the input field and run validate. Each line receives an individual VALID or INVALID verdict, and a summary count of valid and invalid entries is shown at the end of the output.