Random UUID v3 Generator
Generate namespace-based UUID version 3 identifiers using MD5 hashing - deterministic, reproducible UUIDs from namespace and name combinations
Our UUID v3 generator creates namespace-based universally unique identifiers using MD5 hashing per RFC 4122 standards. Generate UUID version 3 from namespace identifiers (DNS, URL, OID, X.500) and custom names for deterministic, reproducible unique IDs. Perfect for generating consistent identifiers from known inputs, content-addressed storage, database migrations, and systems requiring repeatable UUID generation where the same namespace and name always produce identical results.
Related Random Generators
Generate namespace-based UUID version 5 using SHA-1 hashing. More secure alternative to UUID v3 with stronger cryptographic hash.
Generate random UUID version 4 identifiers using cryptographic randomness. Non-deterministic, purely random UUIDs.
What is UUID v3?
UUID v3 (Universally Unique Identifier version 3) is a namespace-based identifier defined in RFC 4122 that uses MD5 hashing to generate deterministic UUIDs. It combines a predefined namespace identifier (such as DNS, URL, OID, or X.500) with a custom name string, then applies MD5 hashing to produce a 128-bit UUID. The key characteristic of UUID v3 is reproducibility: providing the same namespace and name will always generate the identical UUID, making it ideal for content-addressed systems, database migrations, and scenarios requiring consistent ID generation from known inputs.
The format follows the standard 32 hexadecimal digits in 5 groups: 8-4-4-4-12 (e.g., a3bb189e-8bf9-3888-9912-ace4e6543002). The version field (3) indicates MD5-based generation, while the namespace component ensures global uniqueness across different naming contexts. UUID v3 is particularly valuable when migrating data between systems where maintaining consistent identifiers is critical, generating UUIDs for known entities (like domain names or URLs), or creating deterministic identifiers for testing and development environments. While MD5 is considered cryptographically weak for security purposes, it remains perfectly suitable for UUID generation where collision resistance, not cryptographic security, is the primary concern.
UUID v3 Generator Configuration
Namespace Selection
Name Input
Quantity (1-100 UUIDs)
Export Formats
How to Generate UUID v3
[STEP 1] Select Namespace
Choose the appropriate namespace for your use case: DNS for domain names, URL for web addresses, OID for object identifiers, or X.500 for directory names. The namespace prevents collisions between identically-named entities in different contexts.
[STEP 2] Enter Name
Provide the name string to be hashed. For DNS namespace, use domain names (example.com). For URL namespace, use full URLs. The name is combined with the namespace and hashed using MD5 to produce a deterministic UUID.
[STEP 3] Generate & Verify
Click EXECUTE GENERATION to create namespace-based UUIDs. Verify reproducibility by regenerating with the same namespace and name - you'll always get the identical UUID, confirming deterministic behavior.
[STEP 4] Use Consistently
Use UUID v3 for database migrations (maintain same IDs across environments), content-addressed storage (same content = same ID), testing fixtures (predictable test data), and any scenario requiring reproducible identifiers from known inputs.
UUID v3 Best Practices
- _ Namespace Selection - Choose the correct namespace for your data type. Use DNS for domains, URL for web resources, OID for standardized identifiers, and X.500 for directory entries.
- _ Deterministic Benefits - Leverage UUID v3's reproducibility for database migrations, ensuring the same entity gets the same UUID across different environments or migration runs.
- _ MD5 Limitations - UUID v3 uses MD5 hashing, which is cryptographically weak. For security-sensitive applications, use UUID v5 (SHA-1) or v4 (random) instead.
- _ Testing Advantages - Use UUID v3 for test fixtures and development data where predictable, reproducible UUIDs simplify debugging and test assertions.
- _ Content Addressing - Ideal for content-addressed storage systems where the same input data should always produce the same identifier for deduplication.
- _ Migration from Sequential IDs - When migrating from auto-increment IDs, UUID v3 allows recreating the same UUIDs from original data, maintaining referential integrity across multiple migration attempts.
Technical Implementation
UUID v3 follows RFC 4122 specification, using MD5 hashing to combine namespace and name into a deterministic 128-bit identifier:
// UUID v3 Structure (128 bits from MD5 hash) Algorithm: Namespace-Based UUID with MD5 // Predefined Namespace UUIDs (RFC 4122) DNS: 6ba7b810-9dad-11d1-80b4-00c04fd430c8 URL: 6ba7b811-9dad-11d1-80b4-00c04fd430c8 OID: 6ba7b812-9dad-11d1-80b4-00c04fd430c8 X500: 6ba7b814-9dad-11d1-80b4-00c04fd430c8 // Generation Algorithm 1. Convert namespace UUID to 16-byte binary 2. Concatenate namespace bytes + name string (UTF-8) 3. Hash = MD5(namespace_bytes + name_bytes) 4. Set version bits: hash[6] = (hash[6] & 0x0F) | 0x30 5. Set variant bits: hash[8] = (hash[8] & 0x3F) | 0x80 // Format: xxxxxxxx-xxxx-3xxx-yxxx-xxxxxxxxxxxx Example: a3bb189e-8bf9-3888-9912-ace4e6543002