--- title: "UUID Generator" description: "Generate UUIDs in your browser. Create random v4, time-ordered v7, time-based v1, or nil UUIDs in batches of up to 100 for databases, APIs, and distributed systems. No signup required." url: https://findutils.com/generate/uuid-generator/ category: generate --- # UUID Generator Generate UUIDs in your browser. Create random v4, time-ordered v7, time-based v1, or nil UUIDs in batches of up to 100 for databases, APIs, and distributed systems. No signup required. **Use this tool:** [UUID Generator](https://findutils.com/generate/uuid-generator/) ## Programmatic access - REST id `uuid-generate`: POST https://api.findutils.com/api/tools/uuid-generate/execute (reference: https://findutils.com/api/uuid-generate/) - MCP tool `uuid_generate` on https://mcp.findutils.com (reference: https://findutils.com/mcp/uuid-generate/) ## Why use UUIDs? UUIDs (Universally Unique Identifiers) provide a way to generate unique identifiers without a central authority. They're essential for distributed systems, databases, and APIs where you need guaranteed uniqueness across systems and time. ## UUID Tips & Best Practices - Use UUID v4 for most applications. Its 122 random bits are generated from a cryptographically secure source and work well as database keys, object IDs, and tokens. - UUID v1 embeds a 100-nanosecond timestamp and a node identifier. Many libraries use the MAC address as the node; this tool uses a random node with the multicast bit set, so nothing about your hardware is encoded. The timestamp is still readable, so avoid v1 where the creation time must stay private. - UUID v7 (RFC 9562, 2024) is a newer time-ordered format designed specifically for database indexing. It preserves chronological sort order while keeping strong randomness, making it more efficient than v4 for B-tree indexes. - Storing UUIDs as 16-byte binary (BINARY(16) in MySQL, uuid type in PostgreSQL) instead of a 36-character string saves storage and improves index performance by up to 50%. - The probability of a collision among UUID v4 values is approximately 1 in 2^122. You would need to generate about 2.7 quintillion UUIDs to have a 50% chance of a single duplicate. ## Frequently Asked Questions ### What is a UUID? UUID (Universally Unique Identifier) is a 128-bit identifier that's practically guaranteed to be unique. It's commonly used in databases, distributed systems, and software development to identify objects. ### What's the difference between UUID versions? This page generates four kinds. Version 4 is random and the usual choice. Version 7 (RFC 9562) starts with a Unix millisecond timestamp, so values sort by creation time. Version 1 (RFC 4122) starts with a 100-nanosecond timestamp and ends with a node id; this tool uses a random node id with the multicast bit set, as the RFC allows, not a MAC address. The nil UUID is all zeros. Name-based versions 3 and 5 (namespace plus a hash) are not generated here. The same four versions are available through the REST API and the MCP server. ### Are UUIDs truly unique? UUIDv4 has 122 random bits, making collisions astronomically unlikely (1 in 5.3x10^36). For practical purposes, you can generate billions of UUIDs without worrying about duplicates. ### What's the difference between UUID and GUID? UUID and GUID are essentially the same thing. GUID (Globally Unique Identifier) is Microsoft's term for UUID. They follow the same format and can be used interchangeably. ### Can I generate UUIDs without hyphens? Yes! Our tool allows you to copy UUIDs with or without hyphens. The 32-character format without hyphens is useful for certain systems that don't accept special characters. ### Does this UUID generator require a signup? No. This UUID generator is available with no signup, no usage limits. All processing happens in your browser using the Web Crypto API, so nothing is uploaded to a server. ### What is UUID v7 and when should I use it? UUID v7 is a time-ordered UUID format defined in RFC 9562 (2024). It puts a 48-bit Unix millisecond timestamp first and random bits after it, so values sort by creation time. Select Version 7 above to generate them. Use v7 when you need both global uniqueness and efficient database indexing, especially with B-tree indexes in PostgreSQL or MySQL. ### How should I store UUIDs in a database? For best performance, store UUIDs as 16-byte binary (BINARY(16) in MySQL, the native uuid type in PostgreSQL). This uses less storage than a 36-character string and improves index lookup speed. If you must use a string column, use CHAR(36) rather than VARCHAR. ### Can I use UUIDs as API keys or secret tokens? UUID v4 values have 122 bits of entropy from a cryptographically secure source, making them suitable as session tokens or nonces. However, for long-lived API keys you may want a dedicated random key generator that provides 256 bits of entropy for an extra safety margin. ### How many UUIDs can I generate at once? You can generate up to 100 UUIDs in a single batch using this tool. Click Generate, then use Copy All to grab the entire list. There is no daily limit -- generate as many batches as you need. ## Related Tools - [Password Generator](https://findutils.com/security/password-generator/) - [Random Key Generator](https://findutils.com/security/random-key-generator/) - [MD5 Hash Generator](https://findutils.com/security/md5-hash-generator/) - [Base64 Encoder](https://findutils.com/developers/base64-encoder/) - [Unix Timestamp](https://findutils.com/developers/unix-timestamp/) - [Cron Expression Generator](https://findutils.com/developers/cron-expression-generator/) - [Hash Comparison Tool](https://findutils.com/security/hash-comparison-tool/)