UUID Generator

About this tool

The UUID Generator produces RFC 4122-compliant Version 4 (v4) universally unique identifiers directly in your browser. When you open the page, a fresh 128-bit identifier is created immediately without needing to press a button or reload the page. Each UUID v4 contains 122 cryptographically strong pseudorandom bits generated by the browser's built-in Web Crypto API (crypto.randomUUID() and crypto.getRandomValues()), ensuring high entropy and rendering collision probabilities practically zero across distributed environments.

The interface gives you full control over UUID formatting and batch production. You can toggle between standard lowercase characters and UPPERCASE hex digits, or turn hyphens on or off to output compact 32-character hexadecimal strings. When preparing mock records, migrations, or database seed scripts, use the count input or slider to generate up to 100 UUIDs at a time. The single display box includes a one-click copy button, while the batch list offers a dedicated Copy All button to transfer all generated IDs to your clipboard in one tap.

Software engineers, database architects, QA testers, and systems designers rely on UUIDs across everyday workflows. Backend developers use them as distributed database primary keys to prevent ID enumeration vulnerabilities and merge multi-region records without key clashes. QA teams and developers generating mock payloads can format JSON that contains your UUIDs when preparing test fixtures. If you need to store IDs in binary-safe transport or token payloads, pass them through our Base64 Encoder & Decoder. When you need human-readable identifiers for blog posts or search-friendly permalinks instead of random numbers, switch to the Text to Slug Converter.

Privacy and security are built in by default. All random generation, case conversion, and hyphen formatting occur 100% client-side in your web browser. No identifiers, IP addresses, or device data are transmitted to or stored on any server. You can generate IDs safely even in air-gapped environments or while disconnected from the internet, making it entirely safe for production tokens, secure internal session keys, and sensitive database schemas. If you need to transform or evaluate generated ID strings, you can convert UUIDs to upper or lower case, clean up pasted lines with the Whitespace Cleaner, or audit revisions with the Text Diff Checker.

How to use

1. 1Open the page to see a newly generated UUID ready in the top input box. Click Generate whenever you want a fresh ID.
2. 2Adjust the Count box or drag the slider between 1 and 100 to generate multiple UUIDs simultaneously.
3. 3Choose your formatting preferences: toggle between lowercase and UPPERCASE, and turn Hyphens on or off.
4. 4Click the Copy icon next to the single UUID input, or click Copy All below the generated batch to copy all UUIDs to your clipboard.

Example

f47ac10b - 58cc - 4372 - a567 - 0e02b2c3d479
└── 8 ──┘   └ 4 ┘  └ 4 ┘   └ 4 ┘   └──── 12 ────┘
                   │      │
                   │      └─ Variant bits (e.g. 8, 9, a, or b for RFC 4122)
                   └──────── Version 4 indicator (always '4')

F47AC10B-58CC-4372-A567-0E02B2C3D479

f47ac10b58cc4372a5670e02b2c3d479

UUID versions explained

Common uses

• Database primary keys: Generate non-sequential, globally collision-free keys across distributed relational and NoSQL databases without coordination or central counters.
• API request IDs: Assign correlation identifiers (X-Request-ID) to track incoming web requests through distributed microservice architectures.
• Unique file names: Create collision-proof object keys and file upload paths for cloud buckets like Amazon S3 and Google Cloud Storage to avoid accidental overwrites.
• Test and seed data: Generate realistic batches of records for database migrations, QA staging suites, and automated test fixtures. To draw random subsets from a list of generated IDs, try our Random Line Picker.

Frequently asked questions