Reference

Changelog

Every breaking change ships as a new API version. The current version is v1; old versions remain operational for at least 12 months after a successor ships.

Versioning policy

The API version is in the URL: /api/v1/... today. A future /api/v2/... will not affect v1 integrations.
Additive changes (new fields on responses, new optional fields on requests, new endpoints) ship inside the existing version. Existing integrations continue to work without any change.
Breaking changes (renamed fields, dropped fields, changed semantics) only ship in a new major version. You opt in by changing the URL prefix in your client.
Old versions stay live for at least 12 months after a successor ships. We announce sunsets in this changelog + via email to every active API account at least 90 days in advance.

Webhooks carry the API version

Every webhook delivery includes the API version of the event it represents in the apiVersion field on the envelope. If you stay on v1 in your client, every webhook delivery to your registered URL stays on v1 too.

v1 — current

2026-06-26 — Platform fee surfaced on API responses

Every /labels/quote rate now returns a platformFeeCents field broken out from customerPriceCents. The platform fee defaults to $0.08 per API-created label.
GET /labels/{id} now returns platformFeeCents + source fields. source is "api" for labels created via this API.
Additive: existing fields unchanged.

2026-06-21 — Initial public release

POST /api/v1/labels/quote — multi-carrier rate fetch.
POST /api/v1/labels/create — buy a quoted rate.
GET /api/v1/labels/{id} — fetch a label.
GET /api/v1/labels — list labels with cursor pagination.
POST /api/v1/labels/{id}/refund — refund a purchased label.
POST /api/v1/addresses/verify — verify + standardise an address.
Webhook subscriptions at /api/v1/webhooks with HMAC-SHA256 signatures.

Deprecation policy

We announce field-level deprecations here at least 90 days before removal. Deprecated fields stay populated during the notice window so existing clients keep working. A field that has been deprecated will be tagged with a JSDoc @deprecatedin any SDK we ship, and we'll email the API account contact when a field they actively read starts emitting deprecation telemetry.

Stay in sync

Subscribe to the developer announcements list at devs@shiponline.app and we'll email changelog entries the same day they ship. Or just bookmark this page — it's the canonical source of truth.