Shopify API + MCP vs Spree Commerce

Shopify API + MCP

Typed GraphQL schemas with quarterly versions supported at least 12 months. Closed platform. You can't self-host or change checkout internals.

Spree Commerce

A self-hosted BSD 3-Clause platform with public OpenAPI files for the Store and Admin APIs, scoped secret keys, documented rate limits and idempotency keys on cart and checkout calls. GitHub lists six security advisories between January and July 2026, four rated High, and the default docs describe the 6.0 release candidate while 5.6.1 is the stable release.

Shopify API + MCP

1. Pin an API version in the URL and plan to move at least once a year. Old versions fall forward to the oldest supported one
2. Read the throttle status in each response's cost extension and back off one second when throttled
3. Send an agent profile in meta on every UCP call, and an idempotency key on every checkout write
4. Check userErrors on every mutation. A 200 response can still carry a failed write
5. Add @shopify/dev-mcp while writing code so the agent checks queries against the current schema

Spree Commerce

1. Send a publishable key in X-Spree-Api-Key on every Store API call. Add X-Spree-Token with the cart token for guest carts, or a customer JWT as a Bearer token
2. Send Idempotency-Key with the cart token or a customer JWT on cart, payment and completion calls. A request carrying only the publishable key is never cached
3. Ask for fields and expand explicitly. Relations are left out by default and limit stops at 100
4. Use a secret key with the narrowest scopes for the Admin API. read_all gives a read-only key, and the CLI's auto-minted local key is read-only
5. Read the docs under /docs/v5 for a 5.6 store. The default docs describe 6.0, which renames shipments to fulfilments and splits carts from orders