> For the complete documentation index, see [llms.txt](https://docs.n8n.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.n8n.io/deploy/host-n8n/configure-n8n/basic-configuration/use-environment-variables/task-runners.md).
# Task runners
{% hint style="info" %}
**File-based configuration**
Unlike the main n8n image, you CANNOT use file-based configuration for secrets in the task runner image. This means that variables with a `_FILE` suffix added will not be recognized.
{% endhint %}
[Task runners](/deploy/host-n8n/configure-n8n/set-up-task-runners.md) execute code defined by the [Code node](/integrations/builtin/core-nodes/n8n-nodes-base.code.md).
## n8n instance environment variables
| Variable | Type | Default | Description |
| ----------------------------------- | ----------------------------------- | --------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `N8N_RUNNERS_ENABLED` | Boolean | `false` | Are task runners enabled. |
| `N8N_RUNNERS_MODE` | Enum string: `internal`, `external` | `internal` | How to launch and run the task runner. `internal` means n8n will launch a task runner as child process. `external` means an external orchestrator will launch the task runner. |
| `N8N_RUNNERS_AUTH_TOKEN` | String | Random string | Shared secret used by a task runner to authenticate to n8n. Required when using `external` mode. |
| `N8N_RUNNERS_BROKER_PORT` | Number | `5679` | Port the task broker listens on for task runner connections. |
| `N8N_RUNNERS_BROKER_LISTEN_ADDRESS` | String | `127.0.0.1` | Address the task broker listens on. |
| `N8N_RUNNERS_MAX_PAYLOAD` | Number | `1 073 741 824` | Maximum payload size in bytes for communication between a task broker and a task runner. |
| `N8N_RUNNERS_MAX_OLD_SPACE_SIZE` | String | | The `--max-old-space-size` option to use for a task runner (in MB). By default, Node.js will set this based on available memory. |
| `N8N_RUNNERS_MAX_CONCURRENCY` | Number | `5` | The number of concurrent tasks a task runner can execute at a time. |
| `N8N_RUNNERS_TASK_TIMEOUT` | Number | `300` | The maximum time, in seconds, a task can run before the runner stops it and restarts. This value must be greater than 0. |
| `N8N_RUNNERS_HEARTBEAT_INTERVAL` | Number | `30` | The interval, in seconds, at which the runner must send a heartbeat to the broker. If the runner doesn't send a heartbeat in time, the task stops and the runner restarts. This value must be greater than 0. |
| `N8N_RUNNERS_INSECURE_MODE` | Boolean | `false` | Whether to disable all security measures in the task runner, for compatibility with modules that rely on insecure JS features. **Discouraged for production use.** |
| `N8N_RUNNERS_TASK_REQUEST_TIMEOUT` | Number | `60` | How long (in seconds) a task request can wait for a runner to become available before timing out. This prevents workflows from hanging indefinitely when no runners are available. Must be greater than 0. |
## Task runner launcher environment variables
| Variable | Type | Default | Description |
| ---------------------------------------- | --------------------------------------------- | ----------------------- | ---------------------------------------------------------------------------------------- |
| `N8N_RUNNERS_LAUNCHER_LOG_LEVEL` | Enum string: `debug`, `info`, `warn`, `error` | `info` | Which log messages to show. |
| `N8N_RUNNERS_AUTH_TOKEN` | String | - | Shared secret used to authenticate to n8n. |
| `N8N_RUNNERS_AUTO_SHUTDOWN_TIMEOUT` | Number | `15` | The number of seconds to wait before shutting down an idle runner. |
| `N8N_RUNNERS_TASK_BROKER_URI` | String | `http://127.0.0.1:5679` | The URI of the task broker server (n8n instance). |
| `N8N_RUNNERS_LAUNCHER_HEALTH_CHECK_PORT` | Number | `5680` | Port for the launcher's health check server. |
| `N8N_RUNNERS_MAX_PAYLOAD` | Number | `1 073 741 824` | Maximum payload size in bytes for communication between a task broker and a task runner. |
| `N8N_RUNNERS_MAX_CONCURRENCY` | Number | `5` | The number of concurrent tasks a task runner can execute at a time. |
## Task runner environment variables (all languages)
| Variable | Type | Default | Description |
| ---------------------------------------- | ------ | ----------------------- | ----------------------------------------------------------------------------------------------------------- |
| `N8N_RUNNERS_GRANT_TOKEN` | String | Random string | Token the runner uses to authenticate with the task broker. This is automatically provided by the launcher. |
| `N8N_RUNNERS_AUTO_SHUTDOWN_TIMEOUT` | Number | `15` | The number of seconds to wait before shutting down an idle runner. |
| `N8N_RUNNERS_TASK_BROKER_URI` | String | `http://127.0.0.1:5679` | The URI of the task broker server (n8n instance). |
| `N8N_RUNNERS_LAUNCHER_HEALTH_CHECK_PORT` | Number | `5680` | Port for the launcher's health check server. |
| `N8N_RUNNERS_MAX_PAYLOAD` | Number | `1 073 741 824` | Maximum payload size in bytes for communication between a task broker and a task runner. |
| `N8N_RUNNERS_MAX_CONCURRENCY` | Number | `5` | The number of concurrent tasks a task runner can execute at a time. |
## Task runner environment variables (JavaScript)
| Variable | Type | Default | Description |
| -------------------------------------- | ------- | ------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `NODE_FUNCTION_ALLOW_BUILTIN` | String | - | Permit users to import specific built-in modules in the Code node. Use \* to allow all. n8n disables importing modules by default. In external mode, set this in the [runners config file](/deploy/host-n8n/configure-n8n/set-up-task-runners.md#configuring-launcher-in-runners-container-in-external-mode) (`/etc/n8n-task-runners.json`) as an `env-override`, not as a container environment variable. |
| `NODE_FUNCTION_ALLOW_EXTERNAL` | String | - | Permit users to import specific external modules (from `n8n/node_modules`) in the Code node. n8n disables importing modules by default. In external mode, set this in the [runners config file](/deploy/host-n8n/configure-n8n/set-up-task-runners.md#configuring-launcher-in-runners-container-in-external-mode) (`/etc/n8n-task-runners.json`) as an `env-override`, not as a container environment variable. |
| `N8N_RUNNERS_ALLOW_PROTOTYPE_MUTATION` | Boolean | `false` | Whether to allow prototype mutation for external libraries. Set to `true` to allow modules that rely on runtime prototype mutation (for example, [`puppeteer`](https://pptr.dev/)) at the cost of relaxing security. |
| `GENERIC_TIMEZONE` | \* | `America/New_York` | The [same default timezone as configured for the n8n instance](/deploy/host-n8n/configure-n8n/basic-configuration/use-environment-variables/timezone-and-localization.md). |
| `NODE_OPTIONS` | String | - | [Options](https://nodejs.org/api/cli.html#node_optionsoptions) for Node.js. |
| `N8N_RUNNERS_MAX_OLD_SPACE_SIZE` | String | | The `--max-old-space-size` option to use for a task runner (in MB). By default, Node.js will set this based on available memory. |
## Task runner environment variables (Python)
| Variable | Type | Default | Description |
| ----------------------------- | ------- | ---------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `N8N_RUNNERS_STDLIB_ALLOW` | String | - | Python standard library modules that you can use in the Code node, including their submodules. Use `*` to allow all stdlib modules. n8n disables all Python standard library imports by default. In external mode, set this in the [runners config file](/deploy/host-n8n/configure-n8n/set-up-task-runners.md#configuring-launcher-in-runners-container-in-external-mode) (`/etc/n8n-task-runners.json`) as an `env-override`, not as a container environment variable. |
| `N8N_RUNNERS_EXTERNAL_ALLOW` | String | - | Third-party Python modules that are allowed to be used in the Code node, including their submodules. Use `*` to allow all external modules. n8n disables all third-party Python modules by default. Third-party Python modules must be [included](/deploy/host-n8n/configure-n8n/set-up-task-runners.md#adding-extra-dependencies) in the `n8nio/runners` image. In external mode, set this in the [runners config file](/deploy/host-n8n/configure-n8n/set-up-task-runners.md#configuring-launcher-in-runners-container-in-external-mode) (`/etc/n8n-task-runners.json`) as an `env-override`, not as a container environment variable. |
| `N8N_RUNNERS_BUILTINS_DENY` | String | `eval,exec,compile,open,input,breakpoint,getattr,object,type,vars,setattr,delattr,hasattr,dir,memoryview,__build_class__,globals,locals` | Python built-ins that you can't use in the Code node. Set to an empty string to allow all built-ins. |
| `N8N_BLOCK_RUNNER_ENV_ACCESS` | Boolean | `true` | Whether to block access to the runner's environment from within Python code tasks. Set to `false` to enable all Python code node users access to the runner's environment via `os.environ`. For security reasons, environment variable access is blocked by default. |
---
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