UUID Generator
Generate unique UUID v4 identifiers instantly.
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Generating Unique IDs (UUIDs) That Never Collide
Overview
A UUID (Universally Unique Identifier) is a 128-bit value used to label data so that no two records clash, even across different systems that never talk to each other. Developers use them for database keys, API request IDs, file names, and session tokens. This generator creates standards-compliant UUIDs instantly in your browser, so you can copy one — or a whole batch — without any server call.
How to Use (Step by Step)
- 1
Generate a UUID
Open the tool and a fresh version 4 UUID appears immediately.
- 2
Copy or regenerate
Copy the value with one click, or generate a new one — or a batch — as many times as you need.
- 3
Use it as an identifier
Paste it into your database, code, config, or file name wherever a unique key is required.
How It Works
The tool generates version 4 UUIDs, which are built almost entirely from random numbers produced by your browser's cryptographic random generator. The result is formatted in the canonical 8-4-4-4-12 hexadecimal pattern (like 3f2504e0-4f89-41d3-9a0c-0305e82c3301). Because the values are random and 128 bits wide, the chance of two ever colliding is vanishingly small. Everything happens locally, so no ID is logged or sent anywhere.
When to Use This
Assigning primary keys in a database without a central counter. Tagging API requests or log entries for tracing. Naming uploaded files so they never overwrite each other. Creating idempotency keys for safe retries. Generating test fixtures or placeholder IDs. Producing tokens for temporary links or sessions.
Frequently Asked Questions
Version 4 UUIDs are random 128-bit values, so collisions are astronomically unlikely — you'd need to generate billions before the risk becomes measurable. For practical purposes they're unique.
Important Notes
Version 4 UUIDs are unique but not sequential, which can fragment database indexes — if insert ordering matters, consider a time-ordered ID scheme instead.