# REKOM Loyalty — OnlinePOS Integration

> Integration description, Version 2: OnlinePOS × Nexi Engage × REKOM Loyalty.

- [Integration Description, Version 2](https://docs.loyalty.xeniamoments.com/index.md): OnlinePOS × Nexi Engage × REKOM Loyalty — the REKOM-authored Version 2 of the integration description, for OnlinePOS review.
- [Changes from Version 1](https://docs.loyalty.xeniamoments.com/changelog.md): What changed between OnlinePOS's V1 (28 Aug 2026) / V1-sync (4 Sep 2026) and REKOM's Version 2 (8 Oct 2026).
- [Architecture overview](https://docs.loyalty.xeniamoments.com/architecture/overview.md): The systems involved, the two integration surfaces, and where the REKOM backend sits.
- [Responsibilities](https://docs.loyalty.xeniamoments.com/architecture/responsibilities.md): Who owns what across OnlinePOS, Nexi Engage and the REKOM backend.
- [Phases and activation](https://docs.loyalty.xeniamoments.com/architecture/phases-and-activation.md): Phase 1 (member lookup) and Phase 2 (loyalty basket), and how activation per venue and per module decides what runs.
- [Member identification](https://docs.loyalty.xeniamoments.com/architecture/member-identification.md): How a card becomes a loyalty ID through Nexi Engage, what the loyalty ID is, and what happens when no member is found.
- [Store enrollment](https://docs.loyalty.xeniamoments.com/architecture/store-enrollment.md): How a BAX (terminal setup) is enrolled with Nexi Engage so that Viking terminals can look up members: Option 1, decided 2 Sep 2026.
- [Loyalty basket flow](https://docs.loyalty.xeniamoments.com/architecture/loyalty-basket-flow.md): The synchronous basket call: sequence, latency contract, timeouts and retries, fallback, statuses, the no-change response, the calculation GUID and basket changes after calculation.
- [Basket rules](https://docs.loyalty.xeniamoments.com/architecture/basket-rules.md): What the REKOM backend may change in the basket, how discounts are represented (discount code, note lines, receipt footer), rounding, how existing discounts are kept or swapped, and what OnlinePOS validates.
- [Post-sale and reconciliation](https://docs.loyalty.xeniamoments.com/architecture/post-sale-and-reconciliation.md): The single post-sale event, what is stored on the transaction, the REST sync, receipts, offline sales and how cancellations differ from refunds.
- [Configuration and security](https://docs.loyalty.xeniamoments.com/architecture/configuration-and-security.md): Per-venue activation, webhook registration, request signing, secrets, environments and hosts, limits and timestamps.
- [Decision log](https://docs.loyalty.xeniamoments.com/reference/decision-log.md): Every decision in the integration, with date, status and source, in chronological order.
- [Open points](https://docs.loyalty.xeniamoments.com/reference/open-points.md): Everything still unresolved, with an owner, REKOM's proposal where there is one, and the milestone it blocks.
- [Glossary](https://docs.loyalty.xeniamoments.com/reference/glossary.md): Terms used across OnlinePOS, Nexi and REKOM in this integration.
- [API introduction](https://docs.loyalty.xeniamoments.com/api-reference/introduction.md): Conventions for the REKOM Loyalty Partner API (for OnlinePOS): hosts, headers, money, errors and how the POS treats each response.
- [Calculate loyalty basket](https://docs.loyalty.xeniamoments.com/api-reference/basket/calculate-loyalty-basket.md): Called by the OnlinePOS backend once per basket calculation, after the Nexi Engage lookup returned a loyalty ID and before the amount is authorised.
- [Record sale outcome](https://docs.loyalty.xeniamoments.com/api-reference/sale/record-sale-outcome.md): Sent by the OnlinePOS backend exactly once per `calculationId`, after the transaction is finalised or the payment is abandoned. Never blocks checkout. Replaces Version 1's `loyaltySaleFinalization`, `loyaltySaleCancellation` and `loyaltyOfflineSale`.

## OpenAPI Specs

- [openapi](/api-reference/openapi.yaml)


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