UUID Generator

📖 Tool Introduction

The UUID Generator is a free online tool built for developers, testers and product teams who need to produce globally unique identifiers in bulk, in a single click. When you design database primary keys, idempotency keys for APIs, temporary file names, tracing identifiers, device IDs or large sets of test data, you constantly need random strings that will never collide with anyone else's. UUID version 4 is built from 128 bits of randomness, arranged by the standard into groups of eight, four, four, four and twelve characters for a total of thirty-six characters; the third group starts with the digit four to mark the version, and the fourth group starts with eight, nine, a or b to mark the variant. This tool calls the browser's built-in cryptographically secure random source, crypto.getRandomValues, rather than a plain pseudo-random number generator, so every identifier is as unpredictable as the platform allows. You can ask for anywhere from one to five hundred IDs at once, and the tool deduplicates automatically so that you will never see the same value twice. The interface offers two formatting controls: a case toggle between lowercase and uppercase, and a hyphen toggle that keeps the canonical dashes or strips them into a compact thirty-two-character hex string. Database storage usually prefers the lowercase dashed form, while compact tokens often prefer the undashed form. Results render as a list where each row highlights on hover, and clicking any row copies it straight to the clipboard; you can also copy the whole list at once or download it as a plain text file for use in scripts. The whole process runs fully offline, with no network requests and no uploads, which makes it the quickest way to generate data without writing a throwaway script.

✨ Key Features

• Standard v4: version and variant bits are set strictly per RFC 4122
• Crypto-grade randomness: uses crypto.getRandomValues, not a weak generator
• Batch generation: up to 500 at once, auto-deduplicated for uniqueness
• Format options: lowercase or uppercase, hyphens kept or stripped
• Per-row copy: click any row to copy it, or copy the whole list
• Export: save results as a plain text file for pasting into scripts

📝 How to Use

1. Set how many IDs you need with the stepper or by typing a number
2. Choose lowercase or uppercase, and whether to keep the hyphens
3. Click Generate and watch the list fill with random results
4. Click a single row to copy it, or click Copy All for the whole list
5. Click Download to save the results as a text file when needed

⚠️ Notes

• Count limit: at most 500 IDs per run to keep the browser responsive
• Collision odds: v4 has a theoretically negligible collision chance and is treated as globally unique in practice
• Canonical form: the standard form is 8-4-4-4-12 (36 chars); without hyphens it is 32 hex chars
• Random source: quality depends on the browser crypto source, supported by all modern browsers
• Offline and safe: everything is generated locally and nothing is uploaded, even for sensitive data seeding