UUID / ULID Generator

Generate UUID v1, v4, v7, ULID, and Nano ID. Analyze existing IDs — extract timestamps, detect versions. Custom prefixes, formats, batch generation.

Type
Cryptographically random — most common
Count
Format
Prefix

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APIPOST /api/v1/util/uuid
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Key Features

100% Free

No registration required, unlimited checks

Instant Results

Real-time analysis with detailed output

REST API Access

Integrate into your workflow via API

Accurate Data

Live queries to authoritative sources

What is UUID / ULID Generator?

The UUID/ULID generator creates universally unique identifiers in multiple formats: UUID v1 (timestamp + MAC address), UUID v4 (fully random — the most common), UUID v7 (timestamp-ordered random — recommended for database keys), ULID (Universally Unique Lexicographically Sortable Identifier), and Nano ID (compact, URL-safe). The tool also analyzes existing IDs — paste any UUID and it detects the version, extracts embedded timestamps (v1, v7, ULID), and validates the format. You can generate single IDs or batches, add custom prefixes, and choose output format (standard, no dashes, uppercase).

Unique identifiers are fundamental to modern software: database primary keys, distributed system event tracking, API request correlation, session tokens, file naming, and entity references across microservices. This free ID generator runs in your browser with cryptographically secure randomness.

How to Use

  1. 1Select the ID type you want to generate (UUID v4, v7, ULID, etc.)
  2. 2Configure optional settings like prefix, format, or batch count
  3. 3Click generate to create unique identifiers
  4. 4Paste an existing ID to analyze its version and extract embedded data

Who Uses This

System Administrators

Monitor and troubleshoot infrastructure

Developers

Debug network issues and integrate via API

SEO Specialists

Verify domain configuration and performance

Security Analysts

Audit and assess network security

Frequently Asked Questions

What is the difference between UUID and ULID?
UUID (Universally Unique Identifier) is a 128-bit identifier standardized in RFC 4122 with multiple versions for different use cases. ULID (Universally Unique Lexicographically Sortable Identifier) is also 128 bits but designed specifically for sortability — it encodes a millisecond-precision timestamp in the first 48 bits followed by 80 bits of randomness. This means ULIDs generated later are always lexicographically greater than earlier ones, making them ideal for database primary keys where chronological ordering matters. ULIDs are also more compact in string form (26 characters in Crockford's Base32 vs 36 characters for UUID).
Which UUID version should I use for my project?
UUID v4 (fully random) is the most widely used and the safest default choice — it works well for any application that needs unique identifiers without ordering requirements. UUID v7 (timestamp + random) is the recommended choice for database primary keys — its time-ordered nature improves B-tree index performance and allows rough chronological sorting without a separate timestamp column. UUID v1 embeds timestamp and MAC address — largely replaced by v7 which is more private and equally sortable. ULID is best when you need sortable IDs with a compact representation. Nano ID is ideal for short, URL-safe identifiers.
Can UUID values ever collide?
The probability of a UUID v4 collision is vanishingly small — approximately 1 in 2^122 (5.3 x 10^36). To put this in perspective: if you generated 1 billion UUIDs per second, it would take approximately 100 years to have a 50% chance of a single collision. For all practical purposes in any real-world system, UUID v4 collisions will never happen. UUID v7 and ULID have similarly negligible collision probability. The mathematical guarantee of uniqueness without coordination is what makes UUIDs powerful for distributed systems.
What is Nano ID and when should I use it?
Nano ID generates compact, URL-safe unique identifiers using a customizable alphabet (default: A-Z, a-z, 0-9, - _). Unlike UUIDs which are always 36 characters, Nano ID length is configurable — a 21-character Nano ID has roughly the same collision resistance as UUID v4. Use Nano ID when you need shorter IDs for URLs, file names, or user-visible identifiers where a full UUID would be unwieldy. It's particularly popular in JavaScript/TypeScript projects as a lightweight alternative to UUID.
How do I analyze an existing UUID to find its version and timestamp?
Paste any UUID into the analyzer section of the tool. It automatically detects the version (v1, v3, v4, v5, v7) from the version bits encoded in the UUID, and for time-based versions (v1, v7) extracts the embedded timestamp showing exactly when the ID was generated. For UUID v1, it can also extract the MAC address of the generating machine. For ULID, the tool extracts the millisecond timestamp from the first 48 bits. This analysis is useful for debugging, auditing, and understanding when and how identifiers were created.

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API Endpoint

POST /api/v1/util/uuid
View Documentation