Where I help
Most custom-build work I take is co-design: I scope the app or Function, make the architecture choices, write the spec, and stand up the first working slice. Your team or build partner takes it from there. This keeps custom code small, owned, and auditable.
You probably want a Plus-Fit Assessment first if any of these are true:
- You’re about to commission a custom Shopify app to solve a problem that a Function would handle in a fraction of the code.
- You’re paying per-event for an off-the-shelf app whose pricing has stopped matching your volume.
- You need cart, delivery, discount, or payment customisation at checkout but nobody has confirmed it can be done with native Functions.
- The brief says “custom app” without specifying who owns it post-launch.
What the Plus-Fit gives you for custom work
- Build-vs-buy decision for each piece of custom code — written, with criteria.
- Function-first scoping — what can run inside Shopify’s checkout before any external service exists.
- Architecture for the app if one is genuinely needed: bounded service, single database, Polaris admin UI, hand-back-able.
- Ownership plan — who maintains it, what the runbook says, what the exit looks like.
See Custom Shopify apps — scoping three single-purpose tools for a build-vs-buy advisory engagement.