UUID Generator
Generate cryptographically secure UUIDs in your browser. Supports both UUID v4 (fully random) and UUID v7 (timestamp-ordered, RFC 9562). Bulk generation up to 1000 at once with multiple formatting options.
How to Use the UUID Generator
- Choose version: Select v4 for fully random, unpredictable identifiers — ideal for API keys and session tokens. Select v7 for time-ordered UUIDs that sort naturally, making them optimal for database primary keys.
- Set quantity: Enter any number from 1 to 1,000. All UUIDs are generated instantly in your browser using the OS-level CSPRNG.
- Pick a format: Standard (8-4-4-4-12 with hyphens), no hyphens (32 hex chars), uppercase, or braces — the C# / Microsoft canonical form.
- Copy or download: Click Copy on any row to copy a single UUID, or use Copy All to grab all results. Download .txt exports one UUID per line.
- Re-format on the fly: Change the Format dropdown at any time — existing results are instantly reformatted without regenerating, so you keep the same set of UUIDs.
Frequently Asked Questions
Are these UUIDs cryptographically secure?
Yes. v4 uses the browser's native crypto.randomUUID(), and v7 uses crypto.getRandomValues() for the random portion. Both draw from the OS-level CSPRNG — the same source used for TLS key generation.
What is the difference between UUID v4 and v7?
UUID v4 is fully random (128 bits of entropy minus 6 version/variant bits), making identifiers unpredictable and unordered. UUID v7 (RFC 9562, 2024) embeds a 48-bit Unix millisecond timestamp in the high-order bits, so v7 UUIDs sort chronologically. This makes v7 far better for database B-tree indexes because inserts cluster at the end rather than fragmenting the index.
Do you store or log generated UUIDs?
No. Generation runs entirely in your browser using JavaScript. Nothing is sent to any server. You can disconnect from the internet and the tool will still work.
Can a UUID v7 leak the creation time?
Yes. The first 48 bits of a v7 UUID encode the Unix millisecond timestamp. If the order or timing of ID creation is sensitive — for example, account creation order — prefer v4 instead.
What if my browser does not support crypto.randomUUID?
The tool automatically falls back to a manual implementation using crypto.getRandomValues(), which is supported in all modern browsers including Chrome 37+, Firefox 36+, Safari 7.1+, and Edge.