What is a UUID generator?

It creates unique identifiers - UUID v4 or v7 (128-bit values in 8-4-4-4-12 hex), plus optional ULID and NanoID - for database IDs, API keys, and session tokens.

What is the difference between UUID v4 and UUID v7?

UUID v4 is mostly random (122 random bits). UUID v7 (RFC 9562) puts a Unix millisecond timestamp in the first 48 bits, then random bits, so IDs roughly sort by creation time - helpful for B-tree indexes and log correlation. Both keep the same dashed hex layout.

What are ULID and NanoID?

ULID is a 26-character Crockford Base32 id with a millisecond timestamp plus randomness - sortable like UUID v7 but shorter. NanoID is a compact URL-safe random string (default 21 characters from A-Z, a-z, 0-9, _ -). Neither uses the UUID hyphenated hex format.

Is UUID the same as GUID?

In practice yes for random v4 values. Microsoft often says GUID; the format matches. Read more in UUID vs GUID.

UUID v4 uses 122 random bits. UUID v7 combines a timestamp with random bits. Collision risk is negligible for normal apps. You would need absurd generation rates for a realistic collision.

Is this cryptographically secure?

Where available, UUID v4 uses crypto.randomUUID(). UUID v7, ULID, and NanoID use crypto.getRandomValues when available. Prefer those APIs in production. Never use Math.random()-based IDs for security-sensitive tokens - use a backend crypto library instead.

Can I generate IDs in bulk?

Yes. Set a count (up to 50) and use Copy All to paste the list into code or a spreadsheet.

Developer Tools

Popular

UUID Generator

Create UUID v4, time-sortable UUID v7, ULID, or NanoID in your browser - nothing is uploaded.

Format

How many?

Output

About UUID Generator

Generate RFC 4122 / RFC 9562 UUIDs (also called GUIDs), plus optional ULID and NanoID, in your browser. Pick UUID v4 for classic random IDs, UUID v7 when you want time-sortable primary keys, ULID for a shorter Crockford Base32 form, or NanoID for compact URL-safe strings. Create a single ID or bulk-generate up to 50 values for database keys, API tests, and distributed systems - nothing is uploaded.

How to Use UUID Generator

Choose a format: UUID v4, UUID v7, ULID, or NanoID.
Set how many IDs to generate (and NanoID length if needed).
Click Generate, then copy one ID or use Copy All for bulk seeds and tests.

UUID Generator Formula

UUID v4: 122 random bits in 8-4-4-4-12 hex (version nibble 4, variant 8/9/a/b). UUID v7: 48-bit Unix ms + version 7 + random + variant. ULID: 48-bit ms + 80-bit random as Crockford Base32 (26 chars). NanoID: URL-safe alphabet, default length 21.

UUID Generator Examples

Single UUID v4

550e8400-e29b-41d4-a716-446655440000

UUID v7 (time-sortable)

0191e6b5-8c3a-7c2d-8f1a-2b3c4d5e6f70 - first 48 bits are Unix ms, so newer IDs sort after older ones.

ULID

01ARZ3NDEKTSV4RRFFQ69G5FAV - 26 Crockford Base32 characters, also time-sortable.

NanoID

V1StGXR8_Z5jdHi6B-myT - default 21 URL-safe characters (A-Z, a-z, 0-9, _ -).

Common Use Cases

Database primary keys without central ID servers
Time-sortable UUID v7 or ULID keys for B-tree friendly inserts
Compact NanoID slugs for public URLs and share links
API and integration test fixtures
Client-side IDs before a record is saved
Correlation IDs in logs and distributed systems
Replace auto-increment integers with UUID primary keys in microservices
Generate unique request IDs for Postman or curl API tests

UUID vs GUID

Read the full guide

How to Use UUID Generator: Complete Guide (2026) - 5 min read

Frequently Asked Questions about UUID Generator

What is a UUID generator?: It creates unique identifiers - UUID v4 or v7 (128-bit values in 8-4-4-4-12 hex), plus optional ULID and NanoID - for database IDs, API keys, and session tokens.
What is the difference between UUID v4 and UUID v7?: UUID v4 is mostly random (122 random bits). UUID v7 (RFC 9562) puts a Unix millisecond timestamp in the first 48 bits, then random bits, so IDs roughly sort by creation time - helpful for B-tree indexes and log correlation. Both keep the same dashed hex layout.
What are ULID and NanoID?: ULID is a 26-character Crockford Base32 id with a millisecond timestamp plus randomness - sortable like UUID v7 but shorter. NanoID is a compact URL-safe random string (default 21 characters from A-Z, a-z, 0-9, _ -). Neither uses the UUID hyphenated hex format.
Is UUID the same as GUID?: In practice yes for random v4 values. Microsoft often says GUID; the format matches. Read more in UUID vs GUID.
Are UUIDs unique?: UUID v4 uses 122 random bits. UUID v7 combines a timestamp with random bits. Collision risk is negligible for normal apps. You would need absurd generation rates for a realistic collision.
Is this cryptographically secure?: Where available, UUID v4 uses crypto.randomUUID(). UUID v7, ULID, and NanoID use crypto.getRandomValues when available. Prefer those APIs in production. Never use Math.random()-based IDs for security-sensitive tokens - use a backend crypto library instead.
Can I generate IDs in bulk?: Yes. Set a count (up to 50) and use Copy All to paste the list into code or a spreadsheet.

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