EasyPost vs Ship24

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.

Ship24

The REST API and the hosted MCP server share one public OpenAPI 3.1 spec, numbered rate limits with Retry-After, and tracker creation that is idempotent by payload. No status page, SLA or security certification was found, API keys carry no scopes, and the API agreement and data processing agreement named in the terms aren't published.

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

Ship24

1. Send Authorization: Bearer apik_... to https://api.ship24.com/public/v1. The same key works on the MCP server, which lists tools without a key but answers 401 on calls
2. Store the trackerId or set a unique clientTrackerId. Tracking numbers aren't unique, and any changed field on a repeat POST /trackers creates a second tracker that uses quota
3. Allow up to 60 seconds for the first POST /trackers/track or POST /tracking/search call, since results are fetched from the courier synchronously
4. Cache GET /couriers. It is limited to one request a second and returns the whole courier list, and courier auto-detection usually makes courierCode unnecessary
5. Check for quota_limit_reached and no_active_subscription. POST /tracking/search needs a separate per-call plan, and the free plan blocks at 10 shipments a month