Every practical version
Random v4, time-ordered v7, classic v1, reordered v6, deterministic SHA-1 v5, and the nil and max sentinels defined by RFC 9562.
All tools
Developer identifier utility · Free
UUID Generator
Generate UUID and GUID values in bulk (random v4, time-ordered v7, classic v1, reordered v6, or deterministic v5), then format, export, and decode them without leaving your browser.
Generated with Web Crypto in this browser
Version
Pick a UUID version
Random. The default for database keys, request ids, and anything that needs no ordering.
Batch size
How many
Formatting
Output shape
Letter case
Wrapping
Separator
Generated locally
0 V4 identifiers
Choose a version and select Regenerate to create identifiers.
Web Crypto randomness · nothing uploaded · nothing stored
Inspector
Decode an existing UUID
Paste any UUID or GUID (braced, quoted, unhyphenated, or urn-prefixed) to read its version, variant, and embedded timestamp.
Continue the workflow
Identifiers, digests, and secrets.
Hash Generator
Produce MD5, SHA-1, SHA-256, SHA-384, and SHA-512 digests for text or files, and verify a published checksum.
Password Generator
When you need an actual secret rather than an identifier, generate a high-entropy password or passphrase.
JSON Formatter & Validator
Format and validate the payloads your generated identifiers end up inside.
How it works
128 bits, arranged five different ways.
Every UUID here is the same width; what changes is what the bits mean. Random, time-ordered, or hashed from a name: pick the arrangement that matches how the identifier will be used.
- 01
Choose a version
Version 4 for opaque random keys, version 7 when identifiers should sort by creation time, version 5 when the same input must always produce the same UUID.
- 02
Set the batch and format
Generate up to 1,000 at once, then switch case, hyphens, braces, quotes, or the urn:uuid prefix to match your language or database.
- 03
Copy, download, or decode
Copy one value or the whole list, download it as TXT, JSON, or CSV, then paste any existing UUID into the inspector to read its version and timestamp.
Built for real systems
Bulk generation, exact formatting, and a decoder.
Formatting that matches your target
Lowercase or uppercase, hyphenated or compact, plain, braced, quoted, or urn-prefixed, emitted as lines, a comma list, a JSON array, or CSV.
A decoder, not just a generator
Paste any UUID or GUID to read its version, variant, embedded creation time, clock sequence, and node identifier.
Cryptographic randomness
Random bits come from the Web Crypto API, and the node identifier is randomly generated with the multicast bit set, never your MAC address.
Monotonic inside a millisecond
Version 1, 6, and 7 draws use a per-tab counter, so a fast loop still produces ordered, unique identifiers.
No uploads, no storage
Generation, formatting, and decoding all happen in this browser. Nothing is transmitted and nothing is retained.
UUID questions
Versions, collisions, privacy, and GUID formatting.
Which UUID version should I use?+
Use version 4 when the identifier should reveal nothing and ordering does not matter. Use version 7 for database primary keys, because its leading Unix timestamp keeps inserts sequential and reduces index fragmentation. Use version 5 when the same name must always map to the same identifier.
Are these UUIDs safe to use as security tokens?+
A version 4 UUID has 122 random bits, which is ample for unguessable identifiers. Even so, a UUID is an identifier rather than a secret: do not use one as a password, session token, or API key where a purpose-built token generator is the right tool.
Does a version 1 UUID expose my MAC address?+
Not here. The original specification allowed a real network card address in the node field. This tool generates a random node identifier with the multicast bit set, which is the RFC 9562 recommendation for a random node, so nothing about your hardware is embedded.
What is the difference between a UUID and a GUID?+
None in practice. GUID is Microsoft's name for the same 128-bit identifier. Microsoft tooling often renders it uppercase and inside braces, which is why this tool offers both formats.
Why can two version 5 UUIDs be identical?+
Version 5 is deterministic by design: it is the SHA-1 hash of a namespace and a name. Feeding the same namespace and name always returns the same UUID, which is exactly what makes it useful for stable, reproducible identifiers.
Is the nil UUID a real UUID?+
Yes. The all-zero value is explicitly defined as a sentinel meaning "no identifier", and RFC 9562 added a matching all-ones max UUID as an upper bound. Neither carries a version or variant.
Is anything uploaded to a server?+
No. Random bytes come from your browser's Web Crypto implementation, version 5 hashing uses the browser's SHA-1, and decoding is local parsing. No identifier ever leaves this device.
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