JSON Formatter
Format, validate, minify and explore JSON with precise error locations. Runs locally.
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UUID Generator
Generate random UUID v4 or time-ordered UUID v7 identifiers, one at a time or up to 1,000 in bulk, in the exact format your code needs.
RFC 9562 compliantCryptographically randomGenerated locally
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Options
Version
Bulk UUIDs
Validate & inspect a UUID
UUID versions explained
- Version 4 is 122 bits of randomness plus 6 fixed bits marking the version and variant. It's the most widely used UUID.
- Version 7 (RFC 9562, 2024) starts with a 48-bit Unix timestamp in milliseconds followed by random bits. UUIDs sort by creation time, which makes them ideal primary keys in PostgreSQL, MySQL and other B-tree indexed databases.
- Within the same millisecond this generator increments a counter, so bulk v7 UUIDs stay strictly ordered.
All randomness comes from crypto.getRandomValues, the browser's cryptographically secure generator, and no identifiers are sent anywhere.
FAQ
What is a UUID?
A UUID (universally unique identifier), also called a GUID, is a 128-bit value usually written as 36 characters like 3f2b8c1e-9d4a-4f6b-8e21-5a7c9d0b1e2f. UUIDs can be generated anywhere without coordination and are practically guaranteed to be unique.
Should I use UUID v4 or v7?
Use v7 for database primary keys: it begins with a timestamp so new rows insert in order, which keeps indexes efficient. Use v4 when you want identifiers that reveal nothing about when they were created.
Can two UUIDs ever collide?
In theory, yes; in practice, no. A v4 UUID has 122 random bits. You would need to generate about a billion UUIDs per second for 85 years to have a 50% chance of a single collision.
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