---
sidebar_label: uuid
description: The uuid function generates a unique id.
---

# `uuid` Function

`uuid` generates a unique identifier string.

The id is generated and formatted as required by
[RFC 4122 section 4.4](https://tools.ietf.org/html/rfc4122#section-4.4),
producing a Version 4 UUID. The result is a UUID generated only from
pseudorandom numbers.

This function produces a new value each time it is called, and so using it
directly in resource arguments will result in spurious diffs. We do not
recommend using the `uuid` function in resource configurations, but it can
be used with care in conjunction with
[the `ignore_changes` lifecycle meta-argument](../../language/resources/behavior.mdx#ignore_changes).

In most cases we recommend using [the `random` provider](https://registry.terraform.io/providers/hashicorp/random/latest/docs)
instead, since it allows the one-time generation of random values that are
then retained in the OpenTofu [state](../../language/state/index.mdx) for use by
future operations. In particular,
[`random_id`](https://registry.terraform.io/providers/hashicorp/random/latest/docs/resources/id) can generate results with
equivalent randomness to the `uuid` function.

## Examples

```
> uuid()
b5ee72a3-54dd-c4b8-551c-4bdc0204cedb
```

## Related Functions

* [`uuidv5`](../../language/functions/uuidv5.mdx), which generates name-based UUIDs.
