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UUID generator

Generate RFC 4122 compliant UUID v4 (random) and v1 (time-based) identifiers. Bulk generate up to 1000 at once. Copy to clipboard or download as a CSV file.

Generated UUIDs

What is a UUID?

A UUID (Universally Unique Identifier), also known as a GUID (Globally Unique Identifier), is a 128-bit label used to uniquely identify information in computer systems. The format is xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx, where each x is a hexadecimal digit.

UUID v4 vs UUID v1

UUID v4 is generated using random numbers. It is the most commonly used version for generating database primary keys, session tokens, and API identifiers because it has no correlation to time or machine identity — making it impossible to guess or enumerate.

UUID v1 is generated using the current timestamp combined with a MAC address or random node identifier. It encodes time, which means UUIDs from the same machine in quick succession are related — useful for time-ordered record keeping but potentially a privacy concern if MAC addresses are exposed.

Common uses

API access

Generate UUIDs programmatically: GET /api/v1/network/uuid?version=4&count=100

How unique are UUID v4 values? +
Extremely unique. UUID v4 has 122 bits of randomness (2^122 possible values ≈ 5.3 × 10^36). The probability of generating a duplicate UUID v4 is astronomically small — you would need to generate about 2.7 × 10^18 UUIDs to have a 50% chance of a single collision.
Are UUIDs case-sensitive? +
No. The RFC 4122 standard specifies that UUID strings are case-insensitive. Most systems store them in lowercase but they compare equal regardless of case. This generator outputs lowercase by default.
Can I use UUIDs as database primary keys? +
Yes, and it is a common pattern especially in distributed systems where multiple services need to create records independently without a central ID authority. The trade-off vs auto-increment integers is slightly larger storage (16 bytes vs 4-8 bytes) and less index locality.

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