EasyPost vs Easyship

EasyPost

Docs written for agents (llms.txt, a Markdown copy of each page, a JSON page index), seven official SDKs and free test keys make the REST API easy to start on. No OpenAPI spec or idempotency keys were found, every key has full account access, and the status page shows a connectivity outage on 23 July 2026 that affected all operations.

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.

EasyPost

1. Use a test API key while building. It buys no postage and contacts no carrier, and test tracking codes simulate each tracking status
2. Don't blind-retry POST /shipments/:id/buy after a timeout. Retrieve the shipment first and check for postage_label, since no idempotency key exists
3. Send the API key as the HTTP Basic username with an empty password on the REST API, and as a Bearer token on the MCP server
4. Handle errors as either an array of objects or an array of strings. The docs say both shapes occur
5. Pass a scoped carrier_accounts list when rating. Only the first 60 accounts are rated and the call doesn't fail when more are enabled

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