Random UUID Generator
Generate universally unique identifiers (UUIDs) in multiple versions and formats
Our random UUID generator creates standardized 128-bit universally unique identifiers that are globally unique across space and time. Generate random UUIDs in multiple versions including v4 (random), v7 (time-ordered), v5 (name-based SHA-1), v3 (name-based MD5), and v1 (time-based). Perfect for database primary keys, distributed systems, API development, session identifiers, and any application requiring unique identifiers without central coordination. All UUIDs are generated using cryptographically secure random number generation and comply with RFC 4122 and RFC 9562 standards. Export your generated UUIDs as text, CSV, or JSON for easy integration into your projects.
Related Random Generators
Generate random UUIDs (v4) - the most common format for general-purpose unique identifiers.
Generate time-ordered UUIDs (v7) - recommended for database primary keys and optimal index performance.
Generate time-based UUIDs (v1) with MAC address - legacy format for backward compatibility.
Generate deterministic UUIDs using MD5 (v3) - legacy name-based format.
Generate deterministic UUIDs using SHA-1 (v5) - recommended for reproducible identifiers.
Generate Minecraft UUIDs for online (v4) and offline (v3) modes.
What is a UUID Generator?
A UUID (Universally Unique Identifier) generator creates standardized 128-bit identifiers that are globally unique across space and time. UUIDs are defined by RFC 4122 and RFC 9562, providing a standardized way to generate unique identifiers without requiring a central coordinating authority.
UUIDs are widely used in distributed systems, databases, API design, and software development to ensure uniqueness across different systems, databases, and applications without collision risks. Our random UUID generator API supports all major UUID versions for different use cases.
UUID Version Configuration Options
UUID Version 1 (Time-based)
- Uniqueness: Guaranteed unique per MAC address + timestamp combination
- Ordering: Sortable by generation time (with caveats)
- Privacy: May expose MAC address (hardware identifier)
- Use Cases: Legacy systems, transaction logs, audit trails
- Format: {time_low}-{time_mid}-{time_hi_version}-{clk_seq}-{node}
UUID Version 3 (Name-based MD5)
- Deterministic: Same input always produces same UUID
- Hash Algorithm: MD5 (128-bit output)
- Namespace Required: Predefined (DNS, URL, OID, X500) or custom UUID
- Use Cases: Content-addressable storage, deduplication, idempotent operations
- Security Note: MD5 collisions possible; use v5 for better security
UUID Version 4 (Random)
- Randomness: 122 random bits (6 bits reserved for version/variant)
- Collision Probability: ~1 in 2.7 quintillion for 1 billion UUIDs
- Privacy: No embedded timestamps or hardware identifiers
- Use Cases: General purpose identifiers, session IDs, object IDs, API keys
- Performance: Fast generation, no coordination required
UUID Version 5 (Name-based SHA-1)
- Deterministic: Same input always produces same UUID (reproducible)
- Hash Algorithm: SHA-1 (more secure than MD5)
- Namespace Required: DNS, URL, OID, X500, or custom namespace UUID
- Use Cases: Content addressing, cache keys, data deduplication, migration IDs
- Preferred: Use v5 over v3 for better security and collision resistance
UUID Version 7 (Time-ordered)
- Timestamp: 48-bit Unix epoch milliseconds (sortable until year 10889)
- Randomness: 74 random bits for uniqueness within same millisecond
- Database Optimized: Better B-tree index locality than v4
- Use Cases: Database primary keys, event IDs, distributed tracing, logs
- Recommended: Preferred over v1 for time-ordered UUIDs (no MAC address leak)
Format Options
- With Hyphens (Standard): 8-4-4-4-12 format (e.g., 550e8400-e29b-41d4-a716-446655440000)
- Without Hyphens: 32-character hex string (e.g., 550e8400e29b41d4a716446655440000)
- Uppercase: UPPERCASE hex characters (A-F)
- Lowercase (Default): lowercase hex characters (a-f)
Bulk Generation (1-100 UUIDs)
- Quantity Range: Generate 1-100 UUIDs in a single operation
- Independent Generation: Each UUID properly generated per specification
- Batch Export: Download as TXT, CSV, or JSON
- Use Cases: Database migrations, test data, bulk provisioning
How to Generate UUIDs
[STEP 1] Select UUID Version
Choose v4 for general use, v7 for databases, v5 for deterministic generation, or v1 for legacy support. Each version serves different use cases with specific characteristics and trade-offs.
[STEP 1] Configure Format
Choose whether to include hyphens and select uppercase or lowercase formatting. Standard format includes hyphens for readability, while compact format omits them for storage efficiency.
[STEP 1] Generate & Copy
Click generate, then copy UUIDs to clipboard or export to file. Use bulk generation for database seeding or testing scenarios requiring multiple unique identifiers.
UUID Best Practices
- _ Use UUID v4 for general purpose unique identifiers - Perfect for session IDs, object identifiers, and distributed systems where ordering is not required.
- _ Use UUID v7 for database primary keys - Better index performance and locality than v4 due to time-ordered structure, reducing database fragmentation.
- _ Use UUID v5 when you need deterministic/reproducible identifiers - Same input always produces the same UUID, useful for content-addressable storage and caching.
- _ Never use UUIDs as security tokens or secret keys - UUIDs are identifiers, not cryptographic secrets. Use dedicated token generation for authentication.
- _ Store UUIDs as binary (16 bytes) in databases, not strings (36 bytes) - Binary storage saves space and improves index performance. Most modern databases support native UUID types.
Technical Implementation
Our UUID generator implements RFC 4122 and RFC 9562 standards using cryptographically secure random number generation for random-based versions (v4, v7) and standard hashing algorithms for name-based versions (v3, v5). Time-based versions (v1, v7) use high-precision timestamps with proper entropy.
Algorithm: UUID Generation (RFC 4122/9562) UUID v4 Structure (122 random bits): xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx where 4 = version, y = variant (8,9,A,B) UUID v7 Structure (timestamp + random): tttttttt-tttt-7xxx-yxxx-xxxxxxxxxxxx t = Unix epoch ms, 7 = version Version bits: 4 bits (identifies UUID version) Variant bits: 2 bits (RFC 4122 compliance) Randomness Source: CSPRNG Timestamp Precision: Milliseconds (v7) or 100ns (v1) Hash Functions: MD5 (v3), SHA-1 (v5)