terraform/website/docs/configuration/functions/uuid.html.md

---
layout: "functions"
page_title: "uuid - Functions - Configuration Language"
sidebar_current: "docs-funcs-crypto-uuid"
description: |-
  The uuid function generates a unique id.
---

# `uuid` Function

-> **Note:** This page is about Terraform 0.12 and later. For Terraform 0.11 and
earlier, see
[0.11 Configuration Language: Interpolation Syntax](../../configuration-0-11/interpolation.html).

`uuid` generates a unique identifier string.

The id is a 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
pseudo-random 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](../resources.html#ignore_changes).

In most cases we recommend using [the `random` provider](/docs/providers/random/index.html)
instead, since it allows the one-time generation of random values that are
then retained in the Terraform [state](/docs/state/index.html) for use by
future operations. In particular,
[`random_id`](/docs/providers/random/r/id.html) can generate results with
equivalent randomness to the `uuid` function.

## Examples

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

## Related Functions

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