UUID Generator
Generate universally unique identifiers — v4 (random), v1 (time-based), v7 (time-ordered), Nil and Max UUIDs. Bulk generation, multiple formats, validation and download.
550e8400-e29b-41d4-a716-4466554400004e034bf6-c3fa-4a18-85f2-eca6784fd07e8e0bfeb7-fd35-4960-a7a4-6a35e1a7bd813388b740-3067-4cd4-afef-36c4063450297baf0a98-30e9-4a17-aab8-d9e91c9fdea563c4d8fa-550f-4d79-9976-d6d5ccf4e21ea0487d1b-2263-4531-9804-623ea701ec582686ec95-3a2f-4e55-b965-443ce0c15f6255fd24c3-c112-4958-ab3b-7a16131eec4b38796da5-de18-4276-a71b-4583c39aa6a4106005d1-29f3-4154-a248-3561164e659eWhat is UUID Generator?
A UUID (Universally Unique Identifier) is a 128-bit identifier standardised by RFC 4122 that is designed to be globally unique — the probability of two independently generated UUIDs being identical is astronomically small (approximately 1 in 5.3 × 10^36 for UUIDv4). UUIDs are formatted as 32 hexadecimal characters in the pattern xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx.
UUIDs are used throughout modern software development as unique identifiers for database records, user sessions, transaction IDs, file names, API request tracking, and distributed systems where a central ID authority is impractical. Unlike sequential integer IDs, UUIDs can be generated by any node in a distributed system without coordination and without risk of collision.
UUID version 4 (the most widely used) generates a random UUID using a cryptographically secure random number generator — making it suitable for security-sensitive contexts. UUID version 1 incorporates the current timestamp and network MAC address, making it temporally sortable. Altairys's UUID Generator creates UUIDs using your browser's 'crypto.randomUUID()' API (for v4) or a compliant timestamp-based algorithm (for v1), entirely in-browser with no server requests.
How to Use UUID Generator
- Choose UUID version
Select v4 (random, most common) or v1 (timestamp-based, sortable).
- Set quantity
Choose how many UUIDs to generate — 1 to 100 at once.
- Generate
Click Generate to create a new set of cryptographically random UUIDs instantly.
- Copy individually or all
Copy a single UUID or click Copy All to get all generated UUIDs for bulk use.
Key Benefits
Uses crypto.randomUUID() — the same secure source used in production systems.
Generate up to 100 UUIDs at once for database seeding and test data.
Standard, uppercase, no-hyphens, and URN format outputs available.
New UUIDs appear immediately — no server round-trip required.
Frequently Asked Questions
UUID v1 is based on the current timestamp and MAC address — it encodes when and where it was created, making it sortable chronologically. UUID v4 is fully random, making it better for security-sensitive use cases.
Theoretically yes, but the probability is so small it's effectively impossible. UUID v4 has 2^122 possible values — about 5.3 × 10^36. Generating a duplicate by chance would take longer than the age of the universe.
Yes — GUID (Globally Unique Identifier) is Microsoft's name for UUID. They follow the same RFC 4122 standard and are interchangeable.
Sequential IDs are faster for indexing and joins. UUIDs are better for distributed systems, public-facing IDs (harder to enumerate), and merging data from multiple sources.
UUID v4 generated with crypto.randomUUID() is cryptographically secure and suitable for non-session-critical tokens. For authentication tokens, use purpose-built cryptographic random byte generators.