UUID Generator
Generate secure UUID v4 or sortable v7 IDs in batches, then copy them in the format your code expects.
- Fewer clicks, keyboard friendly
- Features others lock behind paywalls
- More accurate results
Generated UUIDs and saved options stay in this browser. Nothing is uploaded or sent to a server.
How to use
- Choose v4 for a random identifier, or v7 when millisecond time ordering is useful for database keys or events.
- Enter a quantity from 1 to 10,000 and choose the UUID text format your target system accepts.
- Optionally use uppercase letters, then select one UUID per line or a JSON array for copying.
- Select “Generate UUIDs” or press G outside an input field to create a fresh batch.
- Use “Copy all” to put the entire generated batch on your clipboard.
UUID v4 vs. v7: random IDs or time-ordered IDs
RFC 9562 defines a UUID as 128 bits. UUID v4 fills 122 of those bits with random data; the remaining 6 bits identify version 4 and the RFC variant. Use v4 when an identifier should not reveal when it was created. This tool fills those random bits with the browser Web Crypto API, not Math.random().
UUID v7 stores a 48-bit Unix timestamp in milliseconds at the start, followed by 74 random bits and the required version and variant bits. That timestamp prefix means IDs from different milliseconds compare in time order as ordinary UUID strings, which is useful for database and event keys. UUIDs made in the same millisecond can have a random relative order; RFC 9562 allows, but does not require, a counter for stricter within-millisecond monotonicity.
Four UUID text formats, one underlying 16-byte value
The usual UUID string is 32 hexadecimal characters divided as 8-4-4-4-12, for 36 characters including four hyphens: `550e8400-e29b-41d4-a716-446655440000`. The compact form removes the hyphens for systems that require exactly 32 hexadecimal characters. Brace-wrapped values are commonly accepted by Microsoft-oriented APIs, and `urn:uuid:` is the UUID URN representation defined by RFC 9562.
Changing capitalization, hyphens, braces, or a URN prefix changes only the text representation, not the 128-bit UUID value. Choose the format required by the destination rather than converting it later. For code fixtures and seed data, the JSON array option escapes and wraps the generated values as valid JSON.
Why this batch generator uses Web Crypto
The browser `crypto.getRandomValues()` API supplies cryptographically strong random values, unlike `Math.random()`. This generator draws a fresh 16-byte random value for every UUID, then explicitly writes the RFC 9562 version and variant bits before formatting it. All generation, formatting, and copying happen in this browser; saved settings are stored only in this browser’s local storage.
UUIDs are identifiers, not access-control secrets. Use v4 or v7 to label records, requests, files, and test data, but use an authorization system and dedicated security tokens for password resets, login sessions, or other credentials.
Frequently asked questions
What is the difference between UUID v4 and UUID v7?
UUID v4 contains 122 random bits and does not expose a creation time, while UUID v7 stores a 48-bit Unix timestamp in milliseconds followed by 74 random bits. UUID v7 strings therefore sort by time across different milliseconds; v4 is the common choice when ordering is not needed.
Is UUID v7 sortable?
UUID v7 places the Unix time in milliseconds in its first 48 bits, so ordinary string or byte sorting puts values generated in later milliseconds after earlier ones. UUIDs created during the same millisecond use random remaining bits in this tool, so their internal order is not guaranteed.
How many UUIDs can I generate at once?
This UUID generator creates 1 to 10,000 v4 or v7 values in one batch. Copy them as one UUID per line for a spreadsheet or text file, or as a valid JSON array for test fixtures and seed data.
Is a GUID the same as a UUID?
GUID is Microsoft’s name for the same 128-bit identifier format commonly called a UUID. The normal hyphenated representation has 32 hexadecimal characters arranged as 8-4-4-4-12, and this generator can also add braces for systems that expect that notation.
Are UUIDs generated here sent to a server?
No. This generator calls the browser’s Web Crypto API locally, formats the values in the same browser tab, and stores only your selected options in local storage. Generated UUIDs are not uploaded, logged, or sent to a server by this tool.
Can I use a UUID as a password or session token?
A UUID is an identifier rather than an authorization mechanism. UUID v4 and v7 are useful for record IDs, request IDs, and test data, but password resets, login sessions, and similar credentials should use a dedicated token design with appropriate server-side expiry and access controls.
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Updated 2026-10-16