[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [Type](https://evolu.dev/docs/api-reference/common/Type) › UuidV4

```ts
const UuidV4: uuidVersion(4)(Uuid);
```

Defined in: [packages/common/src/Type.ts:10698](https://github.com/evoluhq/evolu/blob/bc4578a260dd15d5bbf94b83765ca05984d194cb/packages/common/src/Type.ts#L10698)

A version 4 [Uuid](https://evolu.dev/docs/api-reference/common/Type/variables/Uuid), made of random bits, as produced by
`crypto.randomUUID()`.

### Example

```ts
import { assertErr, assertOk, UuidV4 } from "@evolu/common";

const value = "20354d7a-e4fe-47af-8ff6-187bca92f3f9";
assertOk(UuidV4.fromUnknown(value), value);
assertErr(UuidV4.fromUnknown("0190a6f4-8c3e-7b2a-9d41-5e6f7a8b9c0d"));
```