UUID & ULID Generator - Bulk & Secure
Generate UUIDs (v4) and ULIDs in bulk. Cryptographically secure, browser-based. Generate up to 50 IDs at once. Free online tool.
UUID v4 - Random
122 bits of cryptographic randomness. Standard format: 8-4-4-4-12 hex digits. Collision probability is negligible (1 in 2^122).
Click Generate to create unique identifiers
What are UUIDs and ULIDs?
A UUID (Universally Unique Identifier) is a 128-bit value used to uniquely identify records in databases, API requests, and distributed systems. Version 4 UUIDs are randomly generated using cryptographic randomness, making collisions practically impossible.
A ULID (Universally Unique Lexicographically Sortable Identifier) combines a 48-bit timestamp with 80 bits of randomness. Unlike UUIDs, ULIDs are sortable by creation time, making them ideal for database primary keys where insertion order matters.
Both formats are generated entirely in your browser using the Web Crypto API. No data is sent to any server. Generate up to 50 identifiers at once, toggle between formats, and copy results with a single click.
How the UUID Generator Works
- 01Click Generate to create a new UUID v4
- 02The UUID is generated using cryptographically secure randomness
- 03Generate multiple UUIDs at once if needed
- 04Copy any UUID to your clipboard with one click
When to Use UUIDs
UUIDs (Universally Unique Identifiers) are 128-bit identifiers that are virtually guaranteed to be unique across all systems without coordination. UUID v4 uses random generation and is the most commonly used version. They are ideal for database primary keys in distributed systems, API resource identifiers, and session tokens. The probability of a collision is astronomically low - about 1 in 5.3 billion billion.
When to Use a UUID Generator
Use UUIDs as database primary keys in distributed systems where auto-incrementing integers would collide, as API resource identifiers that don't reveal record counts, as session tokens and correlation IDs for request tracing, and as unique filenames for uploaded content. Use ULIDs when you need the sortability benefit of timestamps combined with uniqueness.
Common Use Cases
- Generate database primary keys for distributed systems where auto-increment would collide → Hash Generator
- Create unique API resource identifiers that don't reveal record counts or creation order
- Generate correlation IDs for request tracing across microservices
- Create unique filenames for uploaded content to prevent collisions and overwrites
- Generate test data identifiers for development and QA environments → Strong Password Generator
Expert Tips
- Use ULID instead of UUID when you need chronological sorting - the timestamp prefix enables ORDER BY without a separate created_at column
- In PostgreSQL, use gen_random_uuid() for server-side UUID generation rather than generating in application code - it is faster and ensures consistency
- When using UUIDs as URL parameters, consider lowercase format without hyphens for shorter, cleaner URLs
Frequently Asked Questions
What is the difference between UUID and ULID?→
Can UUIDs collide?→
Should I use UUIDs as database primary keys?→
Is this generator secure?→
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Link to this tool
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<a href="https://toolforte.com/tools/uuid-generator">UUID & ULID Generator</a> - MD
[UUID & ULID Generator](https://toolforte.com/tools/uuid-generator)