Flow Functions

Run history and troubleshooting

Every time a function runs - from Flow, from a test, or from the API - it is recorded in History. This page is the first place to look when a workflow behaves unexpectedly.

The History page

Open History in the app navigation. Each row is one run, with its function, status, trigger, and time. You can filter by:

  • Function - one or more functions.
  • Status - Success, Failed, Timeout.
  • Trigger - Flow, Manual, or API.

Open any run to see the full detail: the exact input it received, the output it returned, the logs (ctx.log(...) lines with timestamps), the duration, and an error message if it failed.

Statuses

Status Meaning
Success The function returned without throwing. Its output went back to Flow.
Failed The code threw an error, or returned an error to Flow. The message is on the run detail.
Timeout The run exceeded the function's timeout (Settings tab). Usually a slow external call or an endless loop.

Triggers

Trigger Where it came from Counts against quota?
Flow The Run Function action in a Shopify Flow workflow Yes
Manual The Test button in the editor No
API The REST API or MCP No

Only Flow runs count against your monthly plan quota. See Developer API and MCP.

The first thing to check: what input arrived

Most "it works when I test but not in Flow" problems are input problems. Open the failing Flow run and look at the recorded input.

If it is empty ({}) but you expected fields, the Input (JSON) field on the Flow action is producing invalid JSON - almost always an unquoted Liquid variable. Full detail in Passing variables into your function.

Common errors and fixes

What you see Cause and fix
Input is {} in history The action's Input (JSON) is invalid. Quote your Liquid variables. See Passing variables into your function.
Function must export a default async function The code has no export default. Add export default async function (input, ctx) { ... }.
Compile error A syntax error. The message points at the line.
TIMEOUT A slow external API or a loop. Raise the timeout on the Settings tab, or make the call faster.
An access-denied error from ctx.shopify.graphql The query needs a permission you have not granted. See Permissions and store data access.
Function "..." is disabled Enabled is off on the Settings tab, or a permission it needs was revoked.
No function configured for this action The Flow action has no function selected. Open it and pick one.
Plan limit reached (429) You have used your rolling 30-day quota. Upgrade your plan.
This account has been suspended Contact support.

Retries do not double up

If Flow retries the same action execution, the run is recognised as a duplicate and the earlier successful result is returned instead of running your code again. So a retry does not repeat side effects (like creating a discount twice) and does not consume a second quota slot. See Set up the Run Function action in Shopify Flow.

Alerts

Workflow Functions can email you when usage reaches 80% or 100% of your plan, or when your failure rate climbs. Open the bell on the first dashboard stat card to set thresholds and recipients.

Next steps