Crypto Gift Card API for Digital Platforms

Show only brands valid for the user’s eligible market. Cross-border catalog leakage creates failed fulfillments and support debt. Hard-fail checkout if geo-IP and KYC country disagree beyond your policy threshold.

Support open-value products carefully with min/max validation and clear FX disclosure when crypto funding converts to local face value. Round and disclose conversion so users see the exact face value before confirming crypto spend.

Catalogs go stale. Cache with TTLs, handle SKU retirement, and never sell a denomination the supplier already disabled. Run a nightly catalog sync job and auto-disable SKUs that fail a canary purchase in sandbox or prod.

Use partner API keys with IP allowlists where offered. Rotate credentials and segregate production from sandbox. Prefer short-lived tokens over long-lived static keys when the supplier offers OAuth-style auth.

Verify HMAC (or equivalent), reject replays, and make handlers retry-safe. Acknowledge quickly; process asynchronously. Idempotency keys on fulfillment events prevent double-credit when suppliers retry aggressively.

Normalize supplier errors into stable codes your app can explain. Never expose raw supplier payloads to end users. Map timeout vs supplier reject vs catalog miss to distinct user messages and ops queues.

Debiting an internal user balance works best when you already hold value on your ledger. Confirm the debit is final only after supplier accept—or use a two-phase reserve. Emit ledger entries that finance can reverse cleanly if the supplier later marks the order failed.

External crypto payment adds payment windows, under/overpayment rules, and chain confirmation policy. Document these in UX before go-live. Expire unpaid orders automatically and never fulfill on underpayment without an explicit top-up flow.

Disclose fees, FX, expiry, and refund limits in the purchase path. Gift products often carry brand-specific terms you must surface, not bury. Link brand terms of the gift product at purchase time; burying them only in email creates refund disputes.

The order service owns the state machine and idempotency. It is the source of truth for what the user paid versus what the supplier fulfilled. Expose an admin replay that re-drives webhooks without creating a second charge.

The supplier adapter isolates third-party APIs behind your interface so you can dual-source catalogs later. Circuit-break a failing supplier and fail closed on checkout rather than hanging user funds.

Ops consoles let staff replay webhooks, inspect stuck orders, and trigger refunds under policy. Log every manual intervention. Require a ticket ID on manual refunds and export a monthly exception report for finance.