Easyship vs ShipStation API

Easyship

Per-resource read and write scopes, separate sandbox tokens, a 132-operation OpenAPI contract and a 25-tool hosted MCP server with read-only and destructive annotations on every tool. No idempotency keys or Retry-After were found, the MCP server has no test mode, and the API changelog's last entry is dated 30 October 2025.

ShipStation API

A public OpenAPI 3.1 contract with 173 operations, Markdown docs for agents and a free ShipStation API plan with a sandbox make a first rate quote or test label reachable without a contract. One API key carries full account access, with no scopes, read-only mode or idempotency keys on label purchases.

Easyship

1. Use a sand_ token against https://public-api-sandbox.easyship.com for API tests. Production rejects sandbox tokens, and sandbox allows 6 requests a minute
2. The MCP server calls production only. Create the shipment without buy_label first, then call create_label once the user confirms the courier and price
3. Don't retry a timed-out label purchase blindly. There's no idempotency key, so read the shipment's label_state first
4. Give every item a category or an hs_code. The API rejects shipments and rates requests that have neither
5. Stay under 60 requests a minute and 10 a second, and wait for the next window on 429

ShipStation API

1. Send the key in an API-Key header to https://api.shipstation.com/v2. A key that starts TEST_ runs in the sandbox on the same host
2. Call GET /v2/carriers first. Rate and label calls need carrier_ids or a carrier_id and a service_code from that account
3. Don't blindly retry POST /v2/labels after a timeout. List labels first, then void a duplicate with PUT /v2/labels/{label_id}/void
4. Check the errors array on 2XX responses too, and read error_source to tell a carrier fault from a ShipStation one
5. On a platform (Standard or Premium) key every label is real and charged. Ask the owner before buying, and void test labels at once