Getting Started

Idempotency

Use the Idempotency-Key header to retry safely. LandedFees stores the response for 24 hours and returns the same body on replay.

How it works

Include an Idempotency-Key header (recommended: UUID v4) on any POST request.
The first request runs normally. LandedFees stores the request hash and response for 24 hours.
Retry the same request with the same key: LandedFees returns the cached response and does not re-run the engine or bill quota.
Retry with the same key but a different body: LandedFees returns 409 idempotency_conflict.
After 24 hours, the key expires and a new request runs fresh.

When to use it

Any retry loop over the network. Cron-driven batch imports. Any code path where a partial network failure could otherwise double-persist a calculation or double-bill quota. GET endpoints (/v1/rates/*) do not need idempotency keys because they are already safe.

Idempotent request

curl https://www.landedfees.com/api/v1/calc \
  -H "Authorization: Bearer sk_live_xxx" \
  -H "Idempotency-Key: e4c1d2a0-8f6b-4c9d-a123-2f8b7c5e9d10" \
  -H "Content-Type: application/json" \
  -d @payload.json