Ecwid by Lightspeed vs Shopify API + MCP

Ecwid by Lightspeed

The REST API has 40 access scopes, a published limit of 600 requests a minute per token with Retry-After on a 429, field selection through responseFields, and Markdown docs with an llms.txt index. Tokens never expire, there is no test mode or idempotency key, API access needs a paid plan, and carts are built only in the browser.

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.

Ecwid by Lightspeed

1. Send the token as Authorization: Bearer to https://app.ecwid.com/api/v3/{storeId}. Tokens in the query string stopped working in March 2025
2. Use the secret token server-side only. The public token reads enabled products and places orders that are not marked paid
3. Add responseFields, for example total,items(id,name,price), to keep responses small, and page with offset and limit (maximum 100)
4. Stay under 600 requests a minute per token and wait the Retry-After seconds on a 429. Repeated calls with a bad token get the token and IP blocked for longer
5. Work in a separate test store. There is no test mode, and POST /orders writes a real order with no idempotency key
6. After changing an app's scopes, uninstall and reinstall it, then replace the stored tokens. The old ones stop working

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