A UUID (Universally Unique Identifier) is a 128-bit label used to uniquely identify objects in distributed systems without a central authority. UUIDs are essential for database primary keys, API tokens, session identifiers, and anywhere collision-free unique IDs are needed. This tool generates RFC 4122-compliant UUID v4 (random) and UUID v7 (time-ordered) values entirely in your browser with no data sent to any server.
Format Options
Bulk Generation
UUID Validator
History (Last 10)
How to Use This UUID Generator
A UUID (Universally Unique Identifier) is a 128-bit value used to identify information in computer systems without requiring a central registration authority. UUIDs are formatted as 32 hexadecimal digits displayed in five groups separated by hyphens, following the pattern xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx. This free UUID generator creates standards-compliant identifiers directly in your browser.
Step 1: Choose Your UUID Version
Click Generate UUID v4 for a completely random identifier — the most common choice for database primary keys, API tokens, and general-purpose unique IDs. UUID v4 uses 122 bits of cryptographic randomness, making collisions virtually impossible. If you need time-ordered identifiers that sort chronologically (ideal for database indexing), click Generate UUID v7 instead. UUID v7 embeds a millisecond-precision Unix timestamp in the first 48 bits. You can also generate a Nil UUID (all zeros) for use as a placeholder or default value.
Step 2: Customize the Format
Use the format options to adjust the output. Toggle between lowercase and UPPERCASE depending on your system's conventions. The With Hyphens button switches between the standard hyphenated format and the compact 32-character format without separators. Your format preferences are applied to all subsequent generations, including bulk output.
Step 3: Generate in Bulk
When you need multiple UUIDs at once — for database seeding, test fixtures, or batch operations — use the bulk generation buttons. Click any quantity (5, 10, 25, 50, or 100) to instantly generate a batch. The results appear in a text area that you can copy with one click using the Copy All button. Each UUID appears on its own line for easy pasting into spreadsheets, SQL scripts, or configuration files.
Step 4: Validate Existing UUIDs
Paste any string into the UUID Validator section to check whether it is a valid UUID. The validator verifies the format, checks the version nibble and variant bits, and tells you which UUID version the string represents (v1 through v7, or nil). This is useful when debugging APIs, inspecting database records, or verifying that an identifier conforms to the UUID specification.
Step 5: Copy and Use
Click the Copy button next to the generated UUID to place it on your clipboard instantly. The button provides visual feedback confirming the copy succeeded. Your last 10 generated UUIDs are kept in a session history below the tool, so you can quickly click any previous UUID to copy it again. All processing happens locally in your browser — no UUIDs are ever sent to a server, making this tool safe for generating sensitive identifiers.
Frequently Asked Questions
Is this UUID generator completely free?
Yes, this UUID generator is 100% free with no limits. You can generate single UUIDs or bulk batches of up to 100 at a time, as many times as you need. There are no premium features, no signup, and no restrictions.
Are my generated UUIDs private and secure?
Absolutely. All UUIDs are generated entirely in your browser using JavaScript's cryptographic random number generator (crypto.getRandomValues). No data is ever sent to any server, stored, or logged. Your UUIDs exist only on your screen.
What is the difference between UUID v4 and UUID v7?
UUID v4 is completely random — all 122 bits of data are randomly generated, making collisions virtually impossible. UUID v7 embeds a Unix timestamp in the first 48 bits followed by random data, so UUIDs sort chronologically by creation time. Use v4 when you need pure randomness, and v7 when you need time-ordered identifiers for databases.
What is a UUID and why should I use one?
A UUID (Universally Unique Identifier) is a 128-bit identifier formatted as 32 hexadecimal digits in five groups separated by hyphens (e.g., 550e8400-e29b-41d4-a716-446655440000). UUIDs are used as primary keys in databases, session tokens, API keys, and anywhere you need a globally unique identifier without a central authority.
Can UUID v4 values collide?
While theoretically possible, a UUID v4 collision is extraordinarily unlikely. With 122 random bits, you would need to generate approximately 2.71 quintillion UUIDs before having a 50% chance of a single collision. For all practical purposes, every UUID v4 you generate is unique.
What is a nil UUID?
A nil UUID (also called a null UUID) is the special UUID where all 128 bits are set to zero: 00000000-0000-0000-0000-000000000000. It is defined in RFC 4122 and is commonly used as a placeholder or default value in databases and APIs to represent 'no value' or 'not set'.
Should I use UUIDs with or without hyphens?
The standard format includes hyphens (8-4-4-4-12 pattern), and most systems expect this format. However, some databases and APIs prefer the compact 32-character format without hyphens to save storage space. Our tool lets you toggle hyphens on or off and switch between uppercase and lowercase to match your system's requirements.
How do I validate if a string is a valid UUID?
A valid UUID must be exactly 32 hexadecimal characters (with or without the four standard hyphens), following the 8-4-4-4-12 grouping pattern. The version number appears in the first nibble of the third group, and the variant bits appear in the first nibble of the fourth group. Our validator checks all of these rules and tells you the UUID version.