UUID Generator

Generate random UUID/GUID identifiers instantly

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    How to Use the UUID Generator

    1. Generate a single UUID — Click "Generate One" to instantly create a random UUID v4.
    2. Generate in bulk — Set the count (1-100) and click "Generate Bulk" to create multiple UUIDs at once.
    3. Copy your UUIDs — Click the copy button next to any UUID to copy it, or use "Copy All" to grab them all at once.

    What is a UUID?

    A UUID (Universally Unique Identifier), also known as a GUID (Globally Unique Identifier), is a 128-bit identifier that is guaranteed to be unique across space and time. UUIDs are formatted as 32 hexadecimal digits displayed in five groups separated by hyphens, for example: 550e8400-e29b-41d4-a716-446655440000. They are widely used in software development for database keys, session tokens, file names, API identifiers, and anywhere a unique reference is needed without a central authority.

    Frequently Asked Questions

    Are UUIDs unique?

    Yes, for all practical purposes. UUID v4 uses 122 random bits, giving approximately 5.3 x 1036 possible values. The probability of generating two identical UUIDs is astronomically low — you would need to generate about 2.7 quintillion UUIDs to have a 50% chance of a single collision.

    What is UUID v4?

    UUID v4 is the most common UUID version. Unlike other versions that incorporate timestamps or hardware addresses, v4 UUIDs are generated entirely from random or pseudo-random numbers. The only fixed bits are the version indicator (4) and the variant bits, making them ideal for most applications that need unique identifiers.

    Is this generator secure?

    Yes. This tool uses the browser's built-in crypto.randomUUID() API, which relies on a cryptographically secure random number generator (CSPRNG). All UUIDs are generated entirely in your browser — nothing is sent to any server, and your generated UUIDs remain completely private.

    UUID vs GUID: Are They the Same?

    Yes — UUID and GUID refer to the exact same thing. UUID (Universally Unique Identifier) is the term defined by RFC 4122, used predominantly in Linux, Java, JavaScript, and most open-source ecosystems. GUID (Globally Unique Identifier) is Microsoft's terminology, common in .NET, SQL Server, and Windows development. The format is identical: 32 hexadecimal digits in 8-4-4-4-12 grouping. This online UUID generator produces values that work as both UUID and GUID interchangeably.

    UUID Versions Explained

    RFC 4122 defines several UUID versions, each generated differently:

    • UUID v1: Based on MAC address and timestamp. Predictable but unique per machine.
    • UUID v2: DCE Security version, rarely used.
    • UUID v3: Generated via MD5 hashing of a name and namespace. Deterministic.
    • UUID v4: 122 bits of randomness. The most common version and what this tool generates.
    • UUID v5: Like v3 but uses SHA-1 hashing. Also deterministic.
    • UUID v6/v7/v8: Newer time-based variants (RFC 9562) for better database performance.

    This tool generates UUID v4, which is the recommended choice for most applications that need a random, unique identifier without leaking metadata.

    What is a 128-bit UUID?

    A "128-bit UUID" is just another name for a standard UUID. The 128 bits are split into 32 hexadecimal characters (each character represents 4 bits), formatted as xxxxxxxx-xxxx-Mxxx-Nxxx-xxxxxxxxxxxx. The "M" indicates the version (4 for random UUIDs), and "N" represents the variant. With 128 bits, there are 2128 ≈ 3.4 × 1038 possible values, making collisions practically impossible.

    UETR Generator (SWIFT Payments)

    A UETR (Unique End-to-end Transaction Reference) is a 36-character UUID v4 used to identify SWIFT GPI international payments. UETRs allow banks and treasury systems to track wire transfers in real time. Since UETRs are simply UUID v4 values, you can use this online UUID generator to create valid UETR codes for testing, mock data, or development of payment systems integrating with SWIFT GPI.

    Common Use Cases for Random UUIDs

    • Database primary keys — UUIDs let you generate keys client-side without a central database, perfect for distributed systems.
    • Session tokens — Used for tracking user sessions in web applications.
    • API request IDs — For tracing requests across microservices.
    • File names — Avoid collisions when storing user-uploaded files.
    • Distributed system event IDs — Kafka, EventStore, Kinesis events.
    • Mocking and testing — Generate sample data for unit tests and demos.

    How do I generate a UUID in different programming languages?

    Most modern languages have built-in UUID generation. In JavaScript: crypto.randomUUID(). In Python: import uuid; uuid.uuid4(). In Java: UUID.randomUUID(). In C#: Guid.NewGuid(). In SQL Server: NEWID(). In PostgreSQL: gen_random_uuid() (with pgcrypto extension). This online UUID generator gives you the same result without needing to write code.

    Can I generate multiple UUIDs at once?

    Yes. Set the "Count" field to any number from 1 to 100 and click "Generate Bulk". You will get a list of unique UUIDs that you can copy individually or all at once with the "Copy All" button. This is useful for seeding databases, generating test fixtures, or creating sample data.

    Are random UUIDs really unique?

    For practical purposes, yes. UUID v4 has 122 bits of entropy (122 truly random bits — the other 6 are fixed). To have a 50% chance of generating two identical UUIDs, you would need to produce about 2.71 × 1018 values — approximately 2.7 quintillion. Even at a billion UUIDs per second, you would need 85 years to reach that probability. For all real-world applications, treat them as guaranteed unique.