Medusa API + MCP vs Vendure

Medusa API + MCP

MIT core you can self-host, with Medusa Cloud running the same APIs and no GMV fee. The official MCP server is docs-only and limited to Cloud accounts.

Vendure

Full cart, coupon, shipping and payment flow in the GraphQL Shop API, with ErrorResult types an agent can branch on. No vendor-hosted API. Vendure Cloud is only partly available.

Medusa API + MCP

1. Send x-publishable-api-key on every /store call. It decides which sales channels and products the agent sees
2. Ask for only the fields you need with fields. Store routes reject relations nested more than three deep since 2.20.0
3. Read the store's regions before creating a cart, since prices and shipping options depend on region
4. Place the order with POST /store/carts/{id}/complete after shipping and payment sessions are set
5. Read the release notes before upgrading a minor version. Breaking changes land there

Vendure

1. Keep the session token from the first Shop API response and send it on every call. It holds the active order
2. Check each mutation result's __typename and errorCode. Expected failures return 200 with an ErrorResult
3. Don't retry addItemToOrder blindly. Read the active order first, since a repeat adds the quantity again
4. For server-side work, enable api-key in authOptions.tokenMethod and give the key one role in one channel
5. Run 3.7.3 or later, and purge old job records, which may still hold session tokens