RFC 9562 · Web Crypto · runs in your browser
UUID Generator for v4, v7, v5 & ULID in Bulk
Generate secure UUIDs instantly. This free UUID generator creates random v4, time-ordered v7 and name-based v5 UUIDs, plus ULIDs, up to 10,000 at a time. Choose your format, export to TXT, CSV or JSON, and decode any UUID you paste.
- v4, v7, v5, nil, max and ULID
- Up to 10,000 at once
- UUID decoder
- Nothing sent to a server
UUID decoder and validator
Paste any UUID or ULIDCheck if an ID is valid and see its version, variant and, for time-based UUIDs, when it was created.
- Valid
- –
- Version
- –
- Variant
- –
- Created (UTC)
- –
- 6ID types: v4, v7, v5, nil, max and ULID
- 10,000UUIDs per batch, generated in milliseconds
- 5Export formats: text, CSV, JSON, SQL and copy
- 0Bytes sent to any server
Built for developers
Why use this UUID generator
Most online UUID generators stop at 50 or 100 random v4 IDs. This one covers modern versions, huge batches and decoding in one place.
Time-ordered v7
v7 UUIDs start with a timestamp, so they sort by creation time and keep database indexes fast. Batches stay in order even within the same millisecond.
10,000 in one go
Seed a test database or fixture file in one click, then download it as text, CSV, JSON or ready SQL insert rows.
Decoder and validator
Paste any UUID or ULID to check it, see its version and variant, and read the creation time hidden inside v1, v6, v7 and ULID values.
Deterministic v5
Create stable IDs from a namespace and a name, several at once separated by semicolons, so the same input always maps to the same UUID.
Every common format
Lowercase or uppercase, with or without hyphens, and wrapped in braces, quotes or a URN, to paste straight into code or config.
Secure and private
IDs come from the Web Crypto API, the same source browsers use for encryption keys, and never leave your device.
Takes seconds
How to use the UUID generator
Five steps from zero to a file of IDs.
Choose a version
Use v4 for general IDs, v7 for database keys, v5 for stable IDs from names, or ULID for short sortable strings.
Set how many
Type any number up to 10,000, or tap a quick amount.
Pick the format
Set the case, hyphens and wrapping your code or database expects.
Generate
Press Generate. The first UUID is shown large with its own copy button.
Copy or download
Copy the whole list, or download it as a text, CSV, JSON or SQL file.
Reference
UUID versions explained
All UUIDs are 128 bits, written as 32 hexadecimal characters in five groups: 8-4-4-4-12. The version decides how those bits are made.
| Type | How it is made | Sortable | Best for |
|---|---|---|---|
| v1 | Timestamp plus the machine’s network address | Partly | Legacy systems. It can leak the time and machine. |
| v4 | 122 random bits | No | General IDs, tokens and API resources |
| v5 | SHA-1 hash of a namespace and a name | No | Stable IDs for URLs, emails or domain names |
| v6 | v1 reordered so the time comes first | Yes | Upgrading v1 systems |
| v7 | 48-bit Unix millisecond time plus random bits | Yes | Database primary keys and event IDs |
| Nil | All 128 bits set to 0 | – | A placeholder for “no value” |
| Max | All 128 bits set to 1 | – | An upper bound in ranges |
| ULID | 48-bit time plus 80 random bits, 26 characters | Yes | Short, URL-safe, sortable IDs |
Reading a UUID
In xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx, the digit at M is the version, so a 4 means v4 and a 7 means v7. The first digit at N shows the variant. For standard UUIDs it is 8, 9, a or b.
v4 or v7 for database keys?
Random v4 keys land all over a database index, which slows inserts on large tables. v7 keys grow over time like an auto-increment number, so inserts stay fast, while still being safe to create on any server without coordination.
Can two UUIDs collide?
In practice, no. A v4 UUID has 122 random bits. You would need to create about 2.7 quintillion of them before there was even a 50% chance of one duplicate.
Generate UUIDs in code
// v4 in browsers and Node.js 19+
const id = crypto.randomUUID();
// v7 with the uuid package
import { v7 } from 'uuid';
const sortable = v7();import uuid
print(uuid.uuid4()) # random
print(uuid.uuid5(uuid.NAMESPACE_DNS, 'example.com'))
print(uuid.uuid7()) # Python 3.14+import java.util.UUID;
String id = UUID.randomUUID().toString(); // v4Guid id = Guid.NewGuid(); // v4
Guid sortable = Guid.CreateVersion7(); // .NET 9+import "github.com/google/uuid"
id := uuid.New() // v4
sortable, _ := uuid.NewV7()use Ramsey\Uuid\Uuid;
$id = Uuid::uuid4()->toString();
$sortable = Uuid::uuid7()->toString();-- PostgreSQL 13+ (v4)
SELECT gen_random_uuid();
-- PostgreSQL 18+ (v7)
SELECT uuidv7();
-- MySQL (v1)
SELECT UUID();Answers
UUID generator FAQs
What is a UUID?
A UUID, or universally unique identifier, is a 128-bit value used to label data without a central authority. It is written as 32 hexadecimal characters in five groups, such as 3f2504e0-4f89-41d3-9a0c-0305e82c3301.
What is the difference between a UUID and a GUID?
They are the same thing. GUID, or globally unique identifier, is the name Microsoft uses, while UUID is the standard name. Both use the same format.
Which UUID version should I use?
Use v4 for general-purpose random IDs. Use v7 for database primary keys, because it sorts by creation time and keeps indexes fast. Use v5 when you need the same ID every time for the same name.
Are these UUIDs truly random and secure?
Yes. They are created with the Web Crypto API in your browser, which is a cryptographically secure random source. They are unique, but do not use a UUID on its own as a secret password or access token.
Can two UUIDs ever be the same?
It is possible in theory but not in practice. With 122 random bits, you would need to create about 2.7 quintillion v4 UUIDs before reaching a 50% chance of a single duplicate.
How do I generate many UUIDs at once?
Enter any number up to 10,000 in How many and press Generate. You can then copy the full list or download it as a text, CSV, JSON or SQL file.
What is a UUID v7?
UUID v7, defined in RFC 9562 in 2024, starts with a 48-bit Unix timestamp in milliseconds followed by random bits. New v7 UUIDs sort after older ones, which suits database keys, logs and event streams.
How can I tell which version a UUID is?
Look at the first character of the third group. In 01937f5c-9e4a-7cc5-b7e2-3f1a2b4c5d6e, the 7 means it is a version 7 UUID. Paste any UUID into the decoder above to see its version, variant and timestamp.
What is a ULID?
A ULID is a 26-character sortable identifier made from a 48-bit timestamp and 80 random bits, written in Crockford Base32. It is shorter than a UUID and safe to use in URLs.
Unique IDs, whenever you need them
Bookmark this UUID generator for quick v4 and v7 IDs, bulk test data and decoding IDs from your logs.
Generate UUIDsUUIDs are generated locally in your browser using the Web Crypto API. Nothing you generate or paste is uploaded or stored.