Field Notes · 7 March 2026
When two apps write the same customer field
A field-level conflict pattern we keep finding in storefront customisation reviews — and how to document it.
App stores make it easy to install “just one more” helper. Trouble starts when two helpers believe they own customer.tags, loyalty points, or a discount metafield.
Symptoms
- Tags that disappear overnight
- Loyalty balances that reset after checkout
- Discount codes that apply twice for the same cohort
Documentation habit
During a Customisation Review we build a simple ownership table: field name, writer app, trigger event, and last observed write. Merchants often discover a forgotten trial app still holding credentials.
Remediation order
Remove or reconfigure the lower-value writer first. Re-test the customer path. Only then consider custom scripts. Adding a third writer “to fix” the conflict is how the table grows.
If your admin feels haunted, start with field ownership before another install.