# Error

Start a workflow when another workflow fails.

## Start a workflow

### On Workflow Error

Triggers when a watched workflow's run fails. The failure context lands on the trigger’s data.

- **Watch Workflow · Optional**: Which workflow's failures to handle. Choose 'All workflows' to catch every failure. Default: All workflows.

A later step can use its data, such as `{{trigger.failedStep}}`, `{{trigger.run}}`, `{{trigger.workflow}}`. See [Use data from earlier steps](https://docs.gorunner.io/build/use-data-from-earlier-steps).

For a step-by-step guide, see [Start when another workflow fails or finishes](https://docs.gorunner.io/build/react-to-other-runs).

Not in your list? See [When an app isn’t here](https://docs.gorunner.io/apps/when-an-app-isnt-here#q-not-in-list).

## For developers

In the API, which calls apps pieces, Error is `pieceId: "errortrigger"`. Its trigger is `errortrigger` / `on_error`. [Get an app](https://docs.gorunner.io/api/apps/get-app) returns every field.

Source: https://docs.gorunner.io/apps/error-trigger