Overview
A marketplace platform expanding from India into Southeast Asia and the EU needed one integration surface for cards, bank transfers, and local wallets. Each new country previously required a separate engineering sprint and bespoke reconciliation.
Mobintix built a provider-agnostic gateway in Java with Spring Boot, deployed on AWS behind an API gateway. Adapters normalize request and response shapes per acquirer while a routing engine selects providers based on currency, card BIN, and health checks. Kafka streams webhook events to merchant endpoints with signed payloads and retry policies.
Operations teams use an internal console to replay failed webhooks, compare provider settlement files, and toggle routing weights during incidents.
Challenge
Inconsistent error codes across providers caused merchant integrations to break silently. Failover required manual DNS changes. Finance spent days each month matching provider reports to internal ledger tables across forty currencies.
Approach
We defined a canonical payment intent API with idempotency keys, standardized decline reason mapping, and automatic failover when latency or error thresholds trip. Settlement ingestion parsers normalize each provider format into a unified ledger schema. Merchants receive webhooks with HMAC signatures and delivery logs in a self-serve portal. Load tests validated ten thousand requests per minute with headroom for festival spikes.
Outcomes
- New payment method integrations dropped from months to weeks because adapters plug into the shared core.
- Gateway availability met a 99.9% monthly target during the first production year.
- Finance reconciliation cycles shortened with automated exception reports.
Lessons learned
Idempotency and webhook signing are non-negotiable — build them before the first adapter. Provider sandboxes lie; always run shadow traffic in production with small amounts. Document decline code mapping publicly so merchant developers trust your API.
Maintain a provider status page fed by health checks — transparency during outages preserves merchant trust even when transactions fail.