Chapter 1
Keeping your Functions working
Once it's live, a Function needs two things from you: a look every quarter, and a note that says what it does.
When Scripts stopped running on June 30, 2026, the rules they held moved to Shopify Functions. What's left is three small jobs, and each one needs an owner.
Keeping up with Shopify's updates
Shopify releases a new version of its developer APIs every three months and supports each one for at least 12 months. Every Function is written for one of those versions.
When a version's support ends, Shopify keeps the Function running on the oldest version it still supports. Shopify's own advice is not to rely on that.
Shopify recommends moving to the latest version each quarter. In practice that means someone reads the release notes, tests each Function against the new version, and updates it.
What to ask whoever looks after your Functions:
- Which version is each Function written for?
- Who reads Shopify's release notes each quarter, and when did they last do it?
Spotting a rule that stops working
Shopify records every run of a Function in the developer's Dev Dashboard: when it ran, what it was given and what it returned. It also raises an alert when runs start failing, or when a Function is still on an outdated version.
A Function has a hard limit on how much work it can do each time it runs. If it goes over, Shopify stops it. A larger cart means more work, and Shopify's own guide says a Function that runs close to the limit on a typical cart can fail on a larger one.
What to ask:
- Who checks the run log, and how often?
- Has anything failed in the last quarter?
- Was it tested with a large cart, the kind you see in your biggest week?
The note that saves the next person time
Each Function should have a short note, written while the work is fresh:
- what it does, in plain words
- which Script it replaced
- when it applies, and when it doesn't
- the unusual cases it handles
- the API version it was written for
- what it depends on: product tags, customer tags or metafields
The note is for whoever works on it next. If that's someone new, it saves them reading the code to find out what a discount was meant to do.
If nobody owns the quarterly check, the first sign of a problem can be a customer who didn't get their discount.
One person who knows it's their job can keep on top of this, with a note per Function and a look at the run log each quarter. If a new rule is coming, chapter 2 helps you decide who builds it.