We are looking for an experienced Payments Integration Engineer to stabilize, enhance, and extend our live production system, specifically across: Admin dashboard functionality Multi-provider routing (MID orchestration) Callback/webhook reliability Merchant onboarding and provider configuration tools This is a hands-on, production-critical role requiring strong debugging, payments experience, and the ability to work within an existing deployed ecosystem. Key Responsibilities 1. Admin Dashboard & Login Fixes Diagnose and fix issues in the admin login and dashboard pages Ensure: Authentication works reliably Session handling is stable Dashboard loads without errors Debug frontend-backend interactions for admin panel 2. MID / Terminal Orchestration (Core Task) Ensure 10 MID terminals (merchant provider accounts) are: Properly configured Actively routing transactions Respecting priority/fallback logic Validate: Routing engine selection Provider failover behavior Daily limits and capacity handling 3. Multi-Layer Callback Orchestration Implement and stabilize callback/webhook orchestration Ensure: Provider → SentinelGate → Merchant callback chain works end-to-end Both SUCCESS and FAILURE events are handled Transactions move from PENDING → SUCCESS/FAILED correctly Fix: Missing callbacks Incorrect signature validation Incorrect status mapping Ensure merchant receives final transaction status reliably 4. Merchant Setup & Provider Integration Configure and onboard 10 merchant accounts, including: Provider selection API credential setup Currency configuration MID mapping Ensure: Providers are active and functional Routing is correctly assigned per merchant Fallback providers exist where required 5. Callback URL Validation & Approval Configure and validate approved callback URLs Ensure: HTTPS endpoints are used Callback signature verification works Merchant systems correctly receive POST callbacks Debug: missing callbacks invalid signatures incorrect endpoints 6. Backend Patch — Provider & Merchant Configuration Tools Implement a production-ready patch to allow internal staff/admin users to: Select providers per merchant Enter and manage provider credentials securely Configure callback URLs per merchant Assign MIDs and routing priority Enable/disable providers dynamically This must: Integrate seamlessly into existing Node.js backend Be compatible with current database schema (Prisma or equivalent) Include validation and error handling Avoid breaking live processing 7. Production Debugging & Stability Investigate live transaction failures Trace full payment flow: API → PaymentIntent → Provider → Callback → DB → Merchant Fix: stuck transactions missing records provider failures Ensure system is stable under real payment traffic Technical Environment Backend: Node.js (TypeScript) Architecture: API Gateway (/services/api-gateway) Core services (svc-rails, svc-routing) Database: PostgreSQL (Prisma ORM likely) Deployment: VPS (Linux) Payment Providers: Paystack Seerbit Emergent Hubtel Others (multi-rail orchestration) Required Skills Core Technical Skills Strong Node.js / TypeScript backend development Experience with REST APIs and service orchestration Experience working with Prisma or SQL databases Debugging production systems (logs, DB, APIs) Payments / Fintech Experience (MANDATORY) Experience integrating payment gateways (e.g. Paystack, Stripe, Flutterwave, etc.) Understanding of: payment flows (auth, capture, settlement) webhooks/callbacks transaction states (pending, success, failed) Experience with: multi-provider routing failover systems merchant account/MID management Backend Systems & Architecture Experience with: microservices or service-based architecture API gateways environment-based configs Ability to trace and debug: async workflows callback chains race conditions Security & Best Practices Understanding of: API key management webhook signature validation secure credential storage Ability to avoid: exposing sensitive payment data unsafe DB queries Frontend (Basic — helpful but not required) Ability to debug admin/dashboard UI issues (React/Next.js likely) Fix API integration issues from frontend to backend Preferred Experience PSP / payment orchestration platform experience Experience with: multi-currency systems global payment rails gaming / high-risk merchant flows Experience deploying to VPS (Linux, PM2/systemd) Experience with payment link / hosted checkout systems Success Criteria The role is successful when: Admin dashboard is stable and fully functional All 10 MID terminals are working and routing correctly Callbacks: are received validated update transactions notify merchants 10 merchants are fully onboarded and processing Staff can: configure providers manage credentials assign routing manage callbacks No transactions remain stuck in PENDING without resolution Work Style Independent, proactive problem solver Comfortable working on live production systems Able to read and understand existing codebase quickly Communicates clearly about: issues fixes risks