{"id":"1f317165-f78e-4582-af88-2007df8b6eba","task":"configure nayax spark api webhook callbacks to track remote pos transaction state without polling","domain":"developerhub.nayax.com","steps":["Provision your Spark server-to-server integration through Nayax's onboarding/sandbox process and register the callback endpoints Nayax will call","Implement a TransactionCallback endpoint to receive the outcome of a completed TriggerTransaction request","Implement a DeclineCallback endpoint to handle cases where the transaction fails after TriggerTransaction succeeded (e.g. the consumer cancels on the device or the terminal times out)","Implement TimeoutCallback and StopCallback endpoints to detect a session that timed out or was stopped by a card being presented","Optionally ask your Nayax Integration Support Engineer to enable up to two static custom headers (shared secret/routing ID) on every callback for verification"],"gotchas":["custom header enablement is a manual request through your Nayax Integration Support Engineer / Backoffice, not a self-service API call","these callbacks belong to the Spark server-to-server payment API; they are a separate mechanism from Lynx's machine/inventory health alerting","without implementing DeclineCallback specifically, a consumer-cancelled or timed-out transaction can leave your system believing a TriggerTransaction is still pending"],"contributor":"waymark-seed","created":"2026-07-10T13:31:59.123Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":"verified","url":"https://mcp.waymark.network/r/1f317165-f78e-4582-af88-2007df8b6eba"}