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.
- Free, no sign-up
- REST + MCP
- Updated
- Reviewed by Olgun Ozoktas
How to Generate UUIDs Online
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Select the UUID version
Choose the UUID version you need. Version 4 (random) is the most common choice for general-purpose identifiers. Version 7 encodes a millisecond timestamp and sorts by creation time. Version 1 encodes a 100-nanosecond timestamp with a random node id. Nil is all zeros. -
Set the quantity and format
Enter how many UUIDs you need (up to 100 at once for bulk generation). Choose uppercase or lowercase and whether to include hyphens. -
Generate your UUIDs
Click the Generate button to create your UUIDs instantly. All generation happens in your browser using the Web Crypto API, so nothing is sent to a server. -
Copy and use
Click Copy to grab a single UUID, or use Copy All to get the entire batch. Paste them into your database schema, API code, configuration file, or test data.
Common Use Cases
Database Primary Keys
UUIDs are widely used as primary keys in relational and NoSQL databases. Unlike auto-increment integers, UUIDs can be generated on any client or server without coordination, making them ideal for distributed databases and multi-region architectures.
API Request Identifiers
Assign a unique UUID to every API request for end-to-end tracing. Correlation IDs help you track a request across microservices, search logs quickly, and debug production issues without ambiguity.
Session Tokens and Nonces
UUID v4 values generated from a cryptographically secure random source make strong session tokens, CSRF nonces, and one-time-use codes. Their 122 bits of entropy make brute-force attacks computationally infeasible.
Distributed Systems and Event Sourcing
In event-driven architectures, every event, message, or job needs a globally unique identifier. UUIDs let each node generate IDs independently with virtually zero collision risk, removing the bottleneck of a central ID service.
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.
A UUID (Universally Unique Identifier) is a 128-bit value standardized by RFC 4122 and its successor RFC 9562. UUIDs provide a reliable way to create identifiers that are unique across space and time without requiring a central registration authority. This makes them the default choice for primary keys, correlation IDs, and object references in modern software.
The most common versions are UUID v1 (time-based), UUID v4 (random), and the newer UUID v7 (time-ordered random). Version 1 encodes the current timestamp and a node ID, which guarantees uniqueness but can reveal when and where the ID was created. Version 4 fills 122 of the 128 bits with cryptographically random data, making collisions practically impossible while revealing nothing about the source. Version 7, introduced in RFC 9562 (2024), combines a Unix-epoch millisecond timestamp with random bits, giving you both chronological ordering and strong uniqueness -- ideal for database primary keys that need efficient B-tree indexing.
This UUID generator runs entirely in your browser using the Web Crypto API. No data is transmitted to any server, so your generated IDs remain private. You can create UUIDs in bulk, switch between uppercase and lowercase formats, and remove hyphens for systems that require a compact 32-character string. If you also need deterministic hashes for data verification, check out the SHA-256 Hash Generator or the MD5 Hash Generator.
How it compares
Unlike server-side UUID generators such as uuidgenerator.net, this tool creates UUIDs entirely in your browser. Nothing is uploaded or logged, so your identifiers stay private. You can generate up to 100 UUIDs at once with one click, choose between v4, v7, v1 and nil, toggle hyphens and casing, and copy the full batch instantly. There is no signup, no rate limit -- just a fast UUID generator you can bookmark and use whenever you need it.
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.