UUID Generator Online Free - Generate Random UUID v4

UUID Generator

100% free · Runs 100% in your browser · No signup needed

Sur UUID Generator

The UUID Generator creates version 4 universally unique identifiers - the 36-character strings like 550e8400-e29b-41d4-a716-446655440000 used as database keys, API request IDs, session tokens and file names. Version 4 UUIDs are randomly generated with 122 bits of randomness, making collisions practically impossible.

How to use: 1) Enter how many UUIDs you need (1 to 100). 2) Click Generate UUIDs. 3) Copy them all at once with Copy All, one per line - perfect for pasting into SQL inserts, seed files or test fixtures.

Why use it: Developers need fresh unique IDs constantly - seeding a database, generating test data, creating idempotency keys for payment APIs, or naming uploaded files to avoid collisions. Generating them by hand is out of the question, and writing a script for a one-off need wastes time. This tool produces properly formatted RFC 4122 version 4 UUIDs in a single click.

Key benefits: Cryptographically secure randomness via the Web Crypto API - suitable for security-sensitive identifiers, not just test data. Batch generation up to 100 at once for bulk seeding. Correct version 4 format with the variant bits set properly. Copy-all output formatted for direct pasting into code and queries. Fully client-side, so generated IDs are never logged or transmitted anywhere.

FAQs: What is a UUID v4? A 128-bit identifier with 122 random bits, displayed as 32 hex digits in 5 groups - the 4 in the third group marks the version. Can two UUIDs collide? Theoretically yes, practically no - you would need to generate billions per second for a century to have a meaningful chance. UUID vs GUID? Same thing - Microsoft calls them GUIDs. Are these safe for security tokens? They use crypto-grade randomness, but for session tokens prefer longer dedicated secrets.

Pro tips: Generate a fresh batch for every seeding run instead of reusing IDs across environments - reused IDs are a classic cause of mysterious test failures. Store the Copy All output directly in your seed scripts or migration files. For database primary keys, check whether your database prefers UUID v4 or v7 (time-ordered) for index performance. FistHost keeps this generator free and unlimited for all your testing and development needs.

Related tools: Generate IDs here, then validate data shapes with the JSON Formatter or hash them with the SHA256 Hash Generator for deterministic fingerprints. FistHost keeps the full developer toolkit free and client-side. For bulk operations, generate 100 at a time and paste the whole list straight into your seed files.

How to Use UUID Generator: Step by Step

1. Select the UUID version if options are available — v4 (random) is the standard default and right for almost every use case.
2. Enter how many UUIDs you need in one batch, or use the default batch size.
3. Click Generate and wait a moment for the list to appear.
4. Scan the list to confirm the format looks right (36 characters with hyphens).
5. Copy a single UUID, several, or the entire batch, then paste them into your database seed, config file, test data, or code.

Pro Tips

• UUID v4 values are random and unique enough for IDs, tokens, and filenames — no central registry needed.
• Generate in bulk when seeding test data instead of one at a time.
• Store UUIDs as a native UUID type in your database when supported; it’s faster and smaller than plain text.