Kodigo Labs ToolsHow to use the UUID generator
Pick a version, type how many UUIDs you need (up to 1,000) and press Generate. Turn on Uppercase, No hyphens or Braces to match the format your code or database expects; the list updates straight away. Use Copy all to paste them somewhere, or Download .txt to save one UUID per line.
To check an ID you already have, paste it into the inspector. It tells you whether it is a valid UUID, which version and variant it is, and, for time-based versions, the date and time it was created in UTC and in Philippine time (Asia/Manila).
Example: reading a v7 UUID
Take 0190a4f5-8c2e-7b3a-9f1d-2c4e6a8b0d1f. The first 12 hex digits, 0190a4f58c2e, are the Unix time in milliseconds: 1,720,754,474,030, which is 12 July 2024, 11:21:14 in Manila (03:21:14 UTC). The 7 at the start of the third group is the version. The third group's remaining digits and the whole last group are random, and the 9 that starts the fourth group carries the variant bits 10, which mark a standard RFC 9562 UUID.
UUID v4 vs v7 at a glance
| v4 | v7 | |
|---|---|---|
| Made from | 122 random bits | 48-bit millisecond timestamp + 74 random bits |
| Sortable by time | No | Yes |
| Database index friendly | Poor (random inserts) | Good (appends at the end) |
| Reveals creation time | No | Yes |
Frequently asked questions
Which UUID version should I use?
Use version 4 when you just need a unique random ID. Use version 7 for database primary keys and anything you want to sort by creation time: v7 starts with a timestamp, so new rows are added at the end of an index instead of in random places, which keeps inserts fast. Both have enough randomness that collisions are not a practical concern.
Are these UUIDs really unique?
A v4 UUID has 122 random bits. You would need to generate about a billion UUIDs every second for around 85 years before the chance of a single duplicate reached 50%. v7 has 74 random bits per millisecond, and this tool also keeps values generated in the same millisecond in increasing order, so they never repeat within a batch.
Are the UUIDs generated on a server?
No. They are created in your browser with the Web Crypto API (crypto.randomUUID and crypto.getRandomValues), the same secure random source used for encryption keys. Nothing is sent or logged, so the IDs are known only to you.
Is a UUID the same as a GUID?
Yes. GUID (globally unique identifier) is the name Microsoft uses for the same 128-bit format. Windows and .NET often show GUIDs in uppercase and inside braces, like {3F2504E0-4F89-41D3-9A0C-0305E82C3301}. Use the Uppercase and Braces options to get that style.
Can a v7 UUID reveal when it was created?
Yes. The first 48 bits are the Unix time in milliseconds, so anyone who sees the ID can read its creation time (paste one into the inspector to try it). If that is sensitive, for example in a public URL, use v4 instead.