---
title: "Set up the Run Function action in Shopify Flow"
description: "Add the Run Function action to a Shopify Flow workflow, select your function, pass input, and use the returned output in later steps."
canonical: "https://docs.workflow-functions.app/set-up-the-run-function-action-in-shopify-flow"
---

# Set up the Run Function action in Shopify Flow

Once you have a saved function, you connect it to a workflow with the **Run Function** action in Shopify Flow. This page covers the action's configuration screen, what it sends to your code, and what it gives back to the rest of your workflow.

## Add the action to a workflow

1. Open **Flow** in your Shopify admin and create or edit a workflow.
2. Set up your trigger as usual, for example *Order created*.
3. Click the **+** to add a step and choose **Action**.
4. Search for **Run Function** and select it.

The action now appears in your workflow and needs to be configured.

## The configuration screen

The Run Function action has two parts.

### 1. Function

Click the action, then open its configuration. You get a **Function** dropdown listing every function in your store.

- Pick the function this step should run.
- Disabled functions still appear in the list, marked `(disabled)`. If you select one, the workflow will report an error at run time. Enable it on the function's Settings tab first.
- Click **Save** in the top bar of the configuration screen. You will see a "Configuration saved" confirmation.

The selection is stored per workflow step. If you use the Run Function action twice in the same workflow, each one has its own function selection.

### 2. Input (JSON)

Back on the action itself, there is an **Input (JSON)** field. This is the data your function receives as `input`.

- It must be a JSON object.
- You can insert Flow variables with Liquid, which is how you get the triggering order, product, or customer into your code.
- Leave it blank to pass an empty object `{}`.

A minimal example:

```json
{ "orderId": "{{order.id}}", "threshold": 100 }
```

See [Passing variables into your function](https://docs.workflow-functions.app/passing-variables-into-your-function.md) for the full picture, including how to insert Flow variables, what happens with invalid JSON, and how to handle lists.

## What your function gets back to Flow

When the run succeeds, the action returns three fields you can use in later Flow steps:

| Field | Type | What it holds |
| --- | --- | --- |
| `status` | Text | `SUCCESS` |
| `output` | Text | Your return value, as a JSON string |
| `durationMs` | Number | How long the run took, in milliseconds |

**`output` is a JSON string, not an object.** Flow cannot index into it, so you cannot write `output.tagged`. If you need a single value in a later step, the practical options are:

- Return a plain string or number from your function instead of an object, so `output` is directly usable.
- Do the branching inside your function and act on the result there.
- Split the work across two Run Function steps, where the second one reruns the logic it needs.

## When a run fails

If the function returns an error, times out, or is disabled, the action fails and the workflow stops on that branch. The error message from your function is what Flow shows. Common causes - expand one to see what to do:

### No function configured for this action

Open the action configuration and select a function.

### The configured function no longer exists

The function was deleted. Select another one.

### A function is disabled

Enable it on the function's Settings tab, or grant the permission it needs.

### Plan limit reached

You have used your rolling 30-day run quota. Upgrade your plan.

### This account has been suspended

Contact support.

Every attempt, successful or not, is recorded in **History** in the Workflow Functions app with its input, output, logs, and error. That is the first place to look when a workflow behaves unexpectedly. See [Run history and troubleshooting](https://docs.workflow-functions.app/run-history-and-troubleshooting.md).

## Retries and duplicate runs

If Flow retries the same action execution, the app returns the result of the earlier successful run instead of executing your code a second time. That means a retry does not double-charge your quota and does not repeat side effects such as creating a discount code twice.

This only applies to Flow's own retry of the same action execution. If your workflow itself triggers again, that is a new run.

## Testing the wiring

The fastest way to verify everything is connected:

1. Turn the workflow on in Flow.
2. Trigger it, for example by creating a test order.
3. Open **History** in Workflow Functions. You should see a run with trigger **Flow**.
4. Open the run to check the input Flow actually sent, your logs, and the output.

If the input is empty or missing fields you expected, the problem is almost always the Input (JSON) field on the action, not your code.

## Turning a function off safely

To stop a function without editing your workflows, open the function and turn **Enabled** off on the Settings tab. Flow keeps running the workflow, but the Run Function step reports an error until you enable it again. To stop the workflow entirely, turn the workflow off in Flow.

## Next steps

- [Passing variables into your function](https://docs.workflow-functions.app/passing-variables-into-your-function.md) - the Input (JSON) field in detail.
- [Creating and using secrets](https://docs.workflow-functions.app/creating-and-using-secrets.md) - API keys used by your code.
- [Run history and troubleshooting](https://docs.workflow-functions.app/run-history-and-troubleshooting.md) - confirm the wiring and debug failures.