About the UUID Generator
Overview
A UUID (Universally Unique Identifier) is a 128-bit value often represented as 36 characters with hyphens (e.g. 550e8400-e29b-41d4-a716-446655440000). Version 4 UUIDs are random and suitable for unique IDs in databases, API tokens, or distributed systems. This tool generates one or several UUID v4 values instantly using cryptographically secure randomness.
UUIDs avoid collisions in practice and are standardized (RFC 4122). They do not require a central authority, so different systems can generate them independently. Use the Hash Generator when you need a fixed-length digest of data; use the Password Generator when you need human-readable secrets.
When to use it
Use UUIDs when you need globally unique identifiers: primary keys in databases, session IDs, file names, or correlation IDs in logs. They are ideal for distributed systems where multiple nodes generate IDs without coordination. Use this generator to create test data, placeholder IDs in development, or to quickly get a few UUIDs for scripts. For bulk needs (dozens or hundreds), use the UUID Bulk Generator tool.
How to use it
Click Generate to create a single UUID v4. Use "Generate 5" to produce five UUIDs at once in the text area; copy the block or individual lines as needed. Each value is new and random. Copy the result into your code, database seed, or configuration. No input is required; generation is instant and happens in your browser or on the server for the request.
Tips
Store UUIDs as binary (16 bytes) in databases when possible for efficiency; display as canonical string with hyphens when showing to users or in APIs. Do not use UUIDs as security secrets by themselves—they are predictable in structure; for tokens use the Password Generator or proper cryptographic methods. For bulk generation (e.g. 100+), use the UUID Bulk Generator to stay within tool limits and get a clean list.
Common mistakes
Using UUID v1 (time-based) when you need unpredictability can leak timing information; prefer v4 for anonymity. Treating the UUID string as case-sensitive in comparisons can cause bugs—the standard is case-insensitive but storing in lowercase is common. Generating huge numbers of UUIDs in a tight loop on the client may hit browser limits; for large batches use the bulk tool or server-side generation.