Developer · free
UUID Generator
Generate cryptographically random v4 UUIDs one at a time or in bulk, uppercase optional, with one-click copy and download.
Uses the browser's cryptographically secure random source.
About the UUID Generator
Generate cryptographically random v4 UUIDs one at a time or in bulk, uppercase optional, with one-click copy and download.
UUIDs are generated locally with the Web Crypto API — nothing leaves your device.
How to use the UUID Generator
- Step 1Choose the count (up to 100) and version.
- Step 2Press <strong>Generate</strong>, then copy all or download a .txt file.
- Step 3Toggle Uppercase to switch letter case on the fly.
When people reach for this tool
Fill a column that needs unique identifiers
A batch of v4 values is ready to paste straight into a seed script.
Check that your code copes with unique keys
A run of random identifiers is the quickest way to see whether a conflict path works at all.
Give test data stable, readable references
Referencing a record by a short identifier in a failing test is far easier than by its position.
Practical tips
- Version 4 is the right default. Version 1 exists for systems that need a time component, and it embeds the machine and clock details.
- Generate them in one batch rather than one at a time — it is faster and avoids leaving a half-finished list.
What you get
- UUID v4 (random) and v1 (time-based)
- Cryptographically secure randomness
- Bulk generation up to 100 at once
- One-click copy or download as text file
UUID Generator — FAQ
Are UUIDs generated truly randomly?
v4 UUIDs use crypto.getRandomValues, the browser’s secure random generator. v1 uses the current time and a random node id.
Why have two versions?
v4 is the default choice for almost everything. v1 is helpful when you want sortable, time-ordered identifiers.
What is the difference between version 1 and version 4?
Version 4 is drawn from a cryptographic random source and carries no information about when or where it was made. Version 1 encodes a timestamp and node identifier, which is why it is rarely the right choice today.
Are these values genuinely unique?
Version 4 gives 122 random bits, so a collision is not a practical concern. Still, most databases want a unique index on the column as a safety net.
More developer tools
All 17 other tools in this collection — free, no sign-up, nothing uploaded.
JSON Formatter & ValidatorJSON MinifierBase64 Encoder / DecoderURL Encoder / DecoderHTML FormatterCSS Formatter / MinifierJavaScript Formatter / MinifierXML FormatterSQL FormatterTimestamp ConverterJWT DecoderJWT GeneratorRegex TesterHash GeneratorHTTP Status Code LookupCSV to JSONRoman Numeral Converter