Carrier or app-calculated rates are configured, but missing at checkout?
A September 2026 Shopify Developer Community report reproduced this during Market-driven shipping feature-preview testing. Shopify staff said carrier rates should remain compatible and pointed first to carrier prerequisites rather than a known Market-driven incompatibility.
WHAT SHOPIFY CURRENTLY SUPPORTS
Carrier-calculated shipping remains part of the Markets model.
Shopify’s Market-driven shipping Admin API explicitly supports carrier-calculated shipping options through DeliveryCarrierCalculatedOptionDefinition. Shopify’s July 2026 rollout guidance also says app-provided rates continue to appear alongside merchant rates.
That means a missing carrier rate in a preview shop should not automatically be classified as a migration incompatibility.
FIRST-PASS FAILURE MATRIX
Check the conditions that can suppress a calculated rate.
- Confirm the carrier service is active and associated with the location used for the checkout.
- Verify the shop and location have complete addresses.
- Confirm product and package weights are greater than zero.
- Check whether the target market has shipping enabled and whether its shipping configuration inherits from a parent market.
- Verify the carrier-calculated option is active for the market and applicable product/location conditions.
- Capture the carrier callback request and response for the same checkout attempt.
- Compare a normal development-store checkout with the Market-driven shipping feature preview using the same cart and address.
WHEN IT MAY BE YOUR MIGRATION
Separate rate generation from merchant shipping configuration reads.
Your CarrierService callback can be healthy while the app still has Market-driven shipping migration exposure elsewhere. If your app also reads or writes merchant-owned delivery profiles, audit those code paths separately because merchant-owned shipping configuration is moving into Markets.
Do not rewrite working carrier-rate logic merely because a merchant-owned delivery-profile read is deprecated; isolate the two dependencies and regression-test both.
SHIPREADY
Find the migration dependency before changing rate logic.
The free checker separates merchant-owned profile exposure, app-owned profiles, market/country dependencies and feature-preview readiness.
SOURCES
Shopify Developer Community: carrier-calculated rate follow-up in feature preview ↗
Shopify: Market-driven shipping Admin API ↗
Shopify: Market-driven shipping feature preview ↗
Shopify: CarrierService requirements and rate callbacks ↗
Community reports describe specific environments. Verify current Shopify documentation and reproduce the issue before changing production behavior.