What this tool does
The UUID/GUID Generator creates Universally Unique Identifiers using the version 4 specification, which relies entirely on randomness to ensure uniqueness. UUIDs are 128-bit numbers represented as 32 hexadecimal characters, typically formatted with hyphens for readability. Unlike sequential ID systems that can reveal information about order or scale, UUIDs provide complete randomness while virtually guaranteeing no collisions across different systems and time periods.
Version 4 UUIDs are the standard choice for distributed systems because they don't depend on timestamps, MAC addresses, or centralized coordination. This tool generates them using cryptographically secure randomness, making them suitable for security-sensitive applications. Each UUID is independently random, so you can safely use them for database primary keys, session identifiers, distributed trace IDs, and session tokens without coordination between systems.
The generator supports multiple formatting options to match different system requirements: standard hyphens (8-4-4-4-12 format), uppercase or lowercase, and optional wrapping in braces for systems that expect that format.
How to use
1. **Enter the number of UUIDs** you want to generate in the "Number of UUIDs" field. You can generate 1-100 UUIDs simultaneously.
2. **Configure the format options** using the toggles: Enable "Uppercase" if your system requires UUIDs in uppercase letters, disable it for lowercase. Most modern systems accept either.
3. **Choose whether to include hyphens** using the "Include hyphens" toggle. Standard UUID format is \`550e8400-e29b-41d4-a716-446655440000\`. Disable hyphens for format \`550e8400e29b41d4a716446655440000\` if your system doesn't allow them.
4. **Select "Wrap in braces"** if your system requires UUIDs surrounded by curly braces like \`{550e8400-e29b-41d4-a716-446655440000}\`. Some systems, particularly Microsoft technologies, use this format.
5. **Click "Generate UUID(s)"** to instantly create your random UUIDs with the exact format you specified.
6. **Copy the results** using the copy button. For multiple UUIDs, they're formatted one per line, ready to paste into SQL scripts, configuration files, or batch processing systems.
Who should use this
- **Database engineers** creating primary keys for distributed databases and microservices architectures - **Backend developers** implementing globally unique session tokens, trace IDs, and request identifiers - **DevOps and SRE teams** tracking infrastructure components, containers, and services with unique identifiers - **Distributed systems architects** designing systems where centralized ID coordination isn't possible or desirable - **Game developers** creating unique identifiers for players, sessions, and game instances across multiple servers - **Data warehouse teams** generating unique identifiers for ETL processes, data lineage tracking, and audit trails - **Security professionals** implementing cryptographically unique tokens for authentication and authorization systems - **API developers** creating request IDs and correlation IDs for tracking requests across service boundaries
Practical examples
**Example 1: Database primary keys in PostgreSQL** Generate 100 UUIDs with default settings (lowercase, with hyphens). Copy them and paste into a SQL script: \`INSERT INTO users (id, name) VALUES ('550e8400-e29b-41d4-a716-446655440000', 'User 1');\`. Each user gets a unique, randomly-generated ID that's globally unique and collision-free.
**Example 2: Distributed trace IDs for microservices** Generate a single UUID without hyphens (set length to 1, disable hyphens) for each HTTP request entering your microservices system. Pass this trace ID through all services so you can track a single user's request across 5-10 different microservices. Example trace ID: \`550e8400e29b41d4a716446655440000\`.
**Example 3: Creating 50 test user sessions** For load testing, generate 50 UUIDs with default formatting. Paste them into your test script to create 50 different sessions with unique IDs. Each session gets: \`550e8400-e29b-41d4-a716-446655440000\`, \`6c68e5a0-5d2c-41d9-b825-557766551111\`, etc.
**Example 4: Microsoft SQL Server compatible IDs** For a .NET application using SQL Server, generate UUIDs with uppercase enabled and wrapping braces enabled. Your database receives IDs like \`{550E8400-E29B-41D4-A716-446655440000}\`, which matches the native GUID format in SQL Server and C#.
**Example 5: API request correlation IDs** Generate UUIDs with hyphens and lowercase for your API logging system. When a client makes a request, include one UUID as a correlation ID header. Your logs across all services can then be grouped by this UUID, making debugging distributed requests much easier: \`x-correlation-id: 550e8400-e29b-41d4-a716-446655440000\`.
FAQs
**Q: What's the difference between UUID and GUID?** A: UUID (Universally Unique Identifier) is the standard term used across platforms and languages. GUID (Globally Unique Identifier) is Microsoft's terminology for the same thing. They're functionally identical—a 128-bit identifier. This tool generates both using the same UUID v4 specification.
**Q: Will two UUIDs ever be the same?** A: Theoretically, yes—UUID collision is possible in the way that winning the lottery is possible. Practically, generating one trillion UUIDs per second would give you roughly a 50% chance of collision only after billions of years. For all realistic applications, UUIDs are guaranteed unique.
**Q: Should I use UUIDs for database primary keys?** A: Yes, UUIDs are excellent for primary keys in distributed systems where you can't rely on a central database to assign IDs. However, they're slower than sequential integers and take more storage. Use UUIDs if you need: distributed generation, privacy (sequential IDs reveal scale), or integration between independent systems. Use sequential integers for single-database systems optimized for performance.
**Q: What's UUID version 4?** A: UUID v4 is entirely random. Other versions (v1 uses timestamps, v3/v5 use hashing) depend on external data. Version 4 is ideal for security applications because randomness can't be predicted, making it suitable for security tokens and session IDs. This tool generates only version 4 UUIDs.
**Q: Do I need to store the hyphenated format or can I remove them?** A: Either format represents the same UUID value. Removing hyphens saves 4 characters of storage but makes it slightly harder for humans to read. Databases typically handle both formats seamlessly. Use hyphens for display and logs, remove them for storage optimization if space is constrained.
**Q: Can I use UUIDs in URLs?** A: Yes, absolutely. UUIDs with hyphens are safe in URLs and don't require escaping. However, you'll often see them without hyphens in URLs to save characters: \`/api/users/550e8400e29b41d4a716446655440000\` instead of \`/api/users/550e8400-e29b-41d4-a716-446655440000\`.
**Q: How do I use UUIDs in my application code?** A: Most programming languages have built-in UUID support. JavaScript has Web Crypto API, Python has the \`uuid\` module, Java has \`java.util.UUID\`, .NET has \`System.Guid\`. Typically you parse the string into a native UUID type: \`const id = UUID.parse('550e8400-e29b-41d4-a716-446655440000');\`. Many ORMs and database drivers handle UUID conversion automatically.
**Q: Are UUIDs secure for session IDs?** A: Yes, UUID v4 generated with cryptographically secure randomness is excellent for session IDs. The randomness is completely unpredictable, preventing attackers from guessing valid session IDs. Never use UUID v1 for security (it's based on timestamps and MAC addresses), but v4 is ideal.
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