Docs
Firmly Agentic Commerce
Docs
Set theme to dark (⇧+D)
  1. Docs
  2. Resources
  3. Changelog

Changelog

What’s shipped in the API and these docs, most recent first. Non-breaking additions ship continuously; breaking changes are announced ahead of time through Firmly — none ships without notice.

​​ Recent changes

  • September 22, 2026 — 3-D Secure payment challenges documented; merchant-access guides restored behind sign-in. Complete Order and Place Order can return 409 payment_challenge_required when the issuer requires card verification — not a failure, but a step the shopper completes before you call Resume After Challenge. openapi.json carries the envelope on every route that emits it, so generated clients no longer treat a challenge as a dead end. Available to App IDs opted in via supports_payment_challenge; others keep the previous 422 PaymentChallengeRequired. Separately, the merchant allow-listing and payment-provider guides are published again under For Merchants, behind the same sign-in they had before — contact Firmly for access. Search Products by Query moved from Catalog to Discovery; the previous URL redirects.
  • September 15, 2026 — PayPal Express Checkout documented, express checkout grouped by provider. PayPal’s three-call sequence now has reference pages — Start, Authorize and Complete Order — verified against the API. Express checkout is now grouped per provider, so the Klarna and Google Pay pages moved to /express-checkout/klarna/… and /express-checkout/google-pay/…; the previous URLs redirect. Each provider page carries the availability check and host note for its gateway; the endpoint pages stay self-contained. Note for PayPal integrators: a declined PayPal payment returns 422 CreditCardDeclined despite the name — see Complete Order.
  • September 2, 2026 — Merchant fees itemized on the cart. Cart responses now carry an optional fees array plus a fee_total, so merchant-imposed charges (recycle, regulatory, environmental) are itemized with their own descriptions instead of being folded into tax. Both fields are optional and absent when a cart has no fees, and total is unchanged. See Get Cart, the ShoppingCartV2 schema, and Common types → Fee.
  • August 21, 2026 — Reference accuracy pass. Corrected the documented shapes for place-order / complete-order (the response carries submitted_at alongside platform_order_number), Get Product from URL (full product detail, and it can return 412 ProductNotSupported), Discovery search (paginate with cursor; query is optional when you send filters), Add Line Item (flush_cart/fast_mode are the strings "true"/"false", and unknown query parameters are rejected), and Set Fulfillment Type (fulfillment_type enum plus location_id). Cart responses now document the session object and the tax / tax_total pairing. Example identifiers are UUIDs throughout, matching what the API returns, and every example card is the documented sandbox card.
  • August 19, 2026 — Clearer Standard vs Advanced. Both checkout flows now have a runnable, end-to-end guide — the Standard Checkout Guide (/api/v1) and the Advanced Checkout Guide (/api/v2) — plus a chooser on the For Destinations and For Merchants pages, and a which-is-my-store heuristic for merchants. The API Explorer is now grouped by flow: Shared setup, Standard (v1), Advanced (v2).
  • August 18, 2026 — Standard (v1) checkout documented end-to-end. New Standard flow reference (catalog, cart, checkout, order) and the runnable Standard Checkout Guide, verified against the sandbox. The Advanced (v2) endpoint set — cart, shipments, orders, sessions, and ZIP-coverage — is now complete in the reference and the Explorer.

​​ How updates are communicated

  • Breaking changes are announced ahead of time through Firmly; no breaking change ships without notice.
  • Non-breaking additions (new endpoints, optional fields, new guides) ship continuously.
  • Internal refactors that don’t change the public contract are not announced.

​​ Versioning

  • Two flows share the same auth and catalog: Standard (/api/v1) — single-merchant, one-shipment checkout, right for most integrations — and Advanced (/api/v2) — split shipments, add-ons, delivery scheduling, and coverage. See Choose your checkout flow for how to pick.
  • Endpoint-level detail is in the API Reference and the live API Explorer.