---
name: parallelism
description: Parallelism for --all commands.
type: integer
env:
  - TG_PARALLELISM
---

import { Aside } from '@astrojs/starlight/components';

Sets the maximum number of concurrent unit runs when running commands with `--all` or `--graph`. This helps control resource usage and API rate limits when working with multiple units.

By default, there is no limit, and every unit whose dependencies have finished starts immediately.

For details on how runs are scheduled and guidance on choosing a value, see [Tuning Parallelism](/troubleshooting/performance#tuning-parallelism).

<Aside type="caution">
When using `--parallelism` with provider caching, `terraform init` is always executed sequentially if OpenTofu/Terraform provider plugin cache is configured.

To safely run concurrent operations with provider caching, enable the [Provider Cache Server](/features/caching/provider-cache-server/) instead.
</Aside>
