Payback — Mobile EMI Financing Platform
Co-founder & Lead Developer
A field-agent-facing backend for mobile device financing on installment — agents sell devices on EMI, generate contracts, collect payments, and enforce device lock policies via Android AMAPI integration.
Problem
Mobile device financing in emerging markets relies on manual paperwork, disconnected agents, and no enforcement mechanism if a buyer defaults. There was no integrated system for agents to generate EMI contracts, track payments, and remotely lock devices until full payment.
What I Built
- EMI contract engine — generates installment schedules on contract creation with per-payment tracking
- Agent and distributor management with role-based access control (RBAC)
- Payment collection flow with credit ledger and audit logging
- Android AMAPI device enrollment and lock policy enforcement — remotely lock devices on payment default
- Enrollment token generation flow tied to active contracts
- REST API following OpenAPI spec: auth, contracts, payments, devices, vouchers, and audit endpoints
- Prisma schema with 10 models: User, Distributor, Agent, Contract, ScheduleItem, Payment, Device, EnrollmentToken, AuditLog, CreditLedger
Outcome
- Full backend architecture for device EMI financing from contract generation to payment enforcement
- AMAPI integration enabling remote device locking on payment default
- Audit trail for all agent actions and policy changes
- OpenAPI-documented REST API covering auth, contracts, payments, and device management
Why It Matters
Combines fintech and device management in a single platform — solving a real enforcement problem in mobile financing markets where default risk is high and agents operate in the field. The AMAPI integration turns every financed device into its own collateral.