🔑 UUID Generator
Generate UUID v4, UUID v7, ULID, and Nano IDs. Bulk generation with one click.
Last updated: May 18, 2026 · By Λ
Free UUID & ID Generator
Generate universally unique identifiers instantly. Supports UUID v4 (random), UUID v7 (time-sortable, RFC 9562), ULID (Universally Unique Lexicographically Sortable Identifier), and Nano ID (compact, URL-safe). Generate up to 10,000 IDs at once. Every identifier is minted on your own device with Web Crypto randomness, and creating them fires zero network requests, so the values exist nowhere but your screen until you paste them somewhere. No tracking, completely free.
What is a UUID?
A UUID (Universally Unique Identifier) is a 128-bit value used to identify information in computer systems without requiring a central coordination authority. The most common version, UUID v4, generates identifiers using random or pseudo-random numbers, resulting in a format like 550e8400-e29b-41d4-a716-446655440000. With 2^122 possible values, the probability of generating a duplicate is astronomically small, making UUIDs ideal for distributed systems where multiple machines need to create unique IDs independently.
Beyond UUID v4, modern applications increasingly use newer identifier formats designed for specific needs. UUID v7 (defined in RFC 9562) embeds a timestamp in the first 48 bits, making the IDs time-sortable while remaining unique. ULID (Universally Unique Lexicographically Sortable Identifier) offers similar time-sortability with a compact, case-insensitive representation. Nano ID provides ultra-compact, URL-safe identifiers in just 21 characters. This generator supports all four formats, produces cryptographically secure randomness using the Web Crypto API, and can generate up to 10,000 IDs at once for bulk operations.
How to Use This Tool
- Select your desired ID type from the tabs at the top: UUID v4, UUID v7, ULID, or Nano ID. Each tab shows a brief description of the format.
- Click "Generate" to create a single ID, which appears in the large display area. Click the displayed ID to copy it to your clipboard instantly.
- For bulk generation, set the count (up to 10,000) and click "Generate Bulk." All IDs appear in a scrollable list below.
- Use "Copy All" to copy the entire list of generated IDs, or "Clear" to reset the output.
Key Features
- Four ID Formats - Generate UUID v4 (random), UUID v7 (time-sortable), ULID (lexicographically sortable), and Nano ID (compact, URL-safe) from one tool.
- Cryptographic Randomness - Uses the Web Crypto API (crypto.getRandomValues) for secure random number generation, ensuring IDs are suitable for security-sensitive applications.
- Bulk Generation - Create up to 10,000 IDs at once with a single click, with performance timing shown in the status bar.
- Click to Copy - Click any displayed ID to instantly copy it to your clipboard. No need to manually select text.
- No Server Required - IDs are produced by local JavaScript without any network traffic, so the tool works offline and your IDs remain private.
Frequently Asked Questions
What is the difference between UUID v4 and UUID v7?
UUID v4 is entirely random, with 122 bits of randomness and version/variant bits. UUID v7 encodes a Unix timestamp in milliseconds in the first 48 bits, followed by random data. This means UUID v7 values naturally sort in chronological order, which significantly improves database index performance when used as primary keys. UUID v4 is better when you need no correlation to time.
When should I use ULID instead of UUID?
ULID is a good choice when you need time-sortable IDs with a compact, case-insensitive representation. ULIDs use Crockford's Base32 encoding, resulting in a 26-character string that sorts lexicographically by creation time. They are especially useful in systems that store IDs as strings and benefit from natural sort order, such as DynamoDB or other NoSQL databases.
How collision-resistant is Nano ID?
A default 21-character Nano ID has approximately 126 bits of entropy, which is comparable to UUID v4. You would need to generate roughly 2.5 million IDs to have a 1% probability of at least one collision. For most applications, this level of uniqueness is more than sufficient. The compact, URL-safe format makes Nano IDs ideal for short URLs, session tokens, and file names.
Are these IDs secure enough for authentication tokens?
The IDs generated by this tool use the Web Crypto API, which provides cryptographically strong random values. This makes them suitable for use as session tokens, API keys, and other security-sensitive identifiers. However, for production authentication systems, you should also ensure proper token length, storage, and rotation practices are in place.