UUID Generator

A UUID, or Universally Unique Identifier, is a 128-bit identifier commonly written as 32 hexadecimal characters grouped in an 8-4-4-4-12 pattern. UUIDs help applications create identifiers independently across databases, services, devices, and processes without requesting a sequential number from one central server.

UUID v4 is the random UUID version. Its version and variant bits are fixed by the format, leaving 122 bits for random data. It is a practical general-purpose choice for record IDs, request IDs, test fixtures, file names, and distributed application identifiers when ordering is not required.

UUID v7 is a time-ordered UUID format that places a Unix timestamp in milliseconds at the beginning and uses random data in the remaining bits. It can be useful for identifiers that benefit from approximate chronological sorting, but the embedded time can reveal when the value was created.

Choose UUID v4 or UUID v7, select a quantity from 1 to 1,000, choose the value and batch format, and select Generate UUIDs. Generation, formatting, validation, and download preparation run locally in the browser.

Yes. The UUID Generator is available without an account or paid API call. You can generate a single identifier or a local batch, copy the output, copy a JSON representation, or download the current result.

The dedicated workspace supports 1 to 1,000 identifiers per batch. The quantity is capped in the browser so the page remains responsive and the output remains reviewable. For very large data fixtures use the UUID Bulk Generator which supports up to 5,000 values with advanced export formats.

The value formatter supports standard lowercase with dashes, uppercase with dashes, compact hexadecimal without dashes, braced UUIDs, and the urn:uuid: form. Batch output can be one per line, a JSON array, comma-separated values, or SQL-quoted values.

Yes. Choose Uppercase with dashes for systems or documentation that prefer capital hexadecimal characters, or Compact without dashes for fields that require exactly 32 hexadecimal characters. The validator accepts normalized standard, compact, braced, and URN forms.

Yes. Select SQL quoted values as the batch format to produce comma-separated single-quoted identifiers that can be adapted into an INSERT statement. Review escaping and the surrounding SQL schema before executing any generated statement.

Yes. Copy JSON creates a JSON array of the current formatted batch. This is useful for test fixtures, seed data, API request bodies, and configuration samples. The JSON output is created in browser memory.

Paste a UUID and select Validate UUID. The validator checks for 32 hexadecimal characters, recognizes standard grouping, braced and URN forms, reads the version nibble, identifies the variant bits, normalizes the canonical form, and reports UUID v7 timestamp metadata when the version is 7.

No. Structural validation proves that a string matches a recognized UUID representation and can report its version and variant. It does not prove who generated the value, whether it already exists in a database, or whether two systems used a safe random source.

No identifier format provides an absolute mathematical guarantee that independently generated values will never collide. UUID v4 is designed to make accidental collisions extraordinarily unlikely when generated with an appropriate random source. Applications should still enforce database uniqueness where uniqueness matters.

No. A UUID is an identifier, not a password, bearer token, session secret, or encryption key. Do not use a UUID as authentication material. Use a dedicated secrets or key-generation design with the correct threat model and rotation policy.

When the browser exposes crypto.getRandomValues, the client uses it to generate random bytes and then sets the UUID version and variant bits. If that API is unavailable, the client displays a warning about its fallback behavior. Review the warning and use a supported cryptographic environment for security-sensitive generation.

No. Generation, formatting, validation, copying, and download preparation run in browser memory. The page does not upload UUIDs to a remote generator API or write them to localStorage or sessionStorage. The optional history is limited to the current page session.

UUID and GUID generally describe the same 128-bit identifier family. GUID is common in Microsoft and .NET contexts, while UUID is the standards-oriented term used across databases, APIs, operating systems, and distributed systems. The representation and version semantics matter more than the label.

Choose according to the database and workload rather than treating one version as universally better. UUID v4 is random and broadly supported. UUID v7 provides time-ordering information that can help some indexes and event streams, but it also exposes approximate creation time. Test index size, insertion behavior, privacy requirements, and native database support.

UUID v7 values are designed to be approximately time-ordered because their leading bits contain a Unix-millisecond timestamp. Sorting can still reflect clock behavior, timestamp precision, random suffixes, and distributed-system timing rather than a guaranteed total order. Use an explicit sequence or event-time field when strict ordering is required.

Yes. The layout stacks controls and output for smaller screens, while buttons and fields remain keyboard and touch accessible. For large batches, a desktop editor may be more comfortable for reviewing the entire output before copying it into a project.

Yes. The current page session keeps a bounded in-memory history of explicit generated batches. Reusing a history item restores its output for copying or downloading, and closing the page clears that history.

Yes. The standalone page includes a local JSON payload preview that replaces {{uuid}} with the first generated value and can show a JSON body, cURL example, or JavaScript fetch-shaped snippet. It does not send a request. Use the UUID Bulk Generator when you need to validate a payload template across an entire batch or export a payload array.

UUID v1 embeds a 60-bit timestamp, so values sort roughly by creation time. This generator uses a random node with the multicast bit set — the RFC 4122 sanctioned way to avoid exposing a real MAC address — and randomizes the sub-millisecond bits since browser clocks are millisecond-precision. For new systems, v7 gives the same time-ordering with a simpler, safer layout.

UUID v5 is deterministic: the same namespace and name always produce the same UUID. It is computed as SHA-1 over the namespace UUID plus your name string, using the browser Web Crypto API locally. Choose the standard DNS, URL, OID, or X.500 namespace — or supply a custom namespace UUID — then enter the name to hash.

That is the point — name-based UUIDs are stable identifiers. Feeding www.example.com into the DNS namespace always yields 2ed6657d-e927-568b-95e1-2665a8aea6a2, the RFC 4122 reference value, which you can use to verify this tool is implementing the spec correctly.

This page is best for generating a handful of UUIDs and for validating, decoding, or choosing between versions 1, 4, 5, and 7. If you need hundreds or thousands of identifiers exported as JSON, CSV, or SQL insert payloads, the dedicated UUID Bulk Generator is built for that workflow.