Mifi Core: A Core Banking System for CEMAC Microfinance

Mifi Core is our core banking platform for microfinance institutions and credit unions operating in the CEMAC region (XAF currency zone), engineered toward COBAC regulatory requirements. Microfinance institutions in Cameroon largely run on spreadsheets, aging desktop software, or imported systems priced and designed for other markets. Mifi Core is currently in beta ahead of institutional pilots.

A core banking system is the hardest category of software to get right: every franc must be accounted for, every action must be attributable, regulators require specific reports and controls, and - uniquely in this market - rural branches lose internet connectivity for hours or days and must keep serving customers anyway. The engineering problem was to build a ledger that cannot silently lose or invent money, a back-office real tellers can operate, a customer mobile experience on par with commercial banks, and an offline story that never permits a double-spend.

The heart of the platform is a double-entry, append-only ledger written in Rust: every transaction balances against system vault accounts, and an automated end-of-day process re-verifies the books daily, accrues interest (Act/365), ages KYC records, and snapshots reconciliation state. Nothing is ever updated in place - corrections are new entries, so history is complete by construction. Around the ledger we built the full suite: a multilingual back-office (Next.js) for admins, branch managers, and tellers; a Flutter mobile app for customers with transfers, savings goals, and loans; and mobile money deposits and withdrawals through MTN and Orange Money via Campay. For rural branches we built Mifi Edge: lightweight branch nodes on SQLite that keep tellers transacting through internet outages and replay their transactions to the core idempotently when connectivity returns - with a zero-double-spend guarantee enforced by the sync protocol.

Rust with Axum for the core banking service; PostgreSQL 16 accessed through SQLx with compile-time-checked queries; Next.js for the back-office; Flutter for the customer mobile app; SQLite for Mifi Edge branch nodes; Campay for MTN and Orange Money integration; Docker for deployment.

Money is never floating point - all monetary arithmetic uses exact decimal representation. The transaction history is append-only, enforced by database triggers, and audit logs are hash-chained so tampering is detectable. High-value operations require maker-checker (four-eyes) approval before execution. Every money-moving endpoint carries idempotency keys backed by database constraints, so retries can never duplicate a movement. Customer PII is encrypted at rest, with keyed blind indexes enabling duplicate detection without decryption. Access is role-based across SuperAdmin, Branch Manager, Teller, and Customer, with Argon2id-hashed credentials and transaction PINs. Mobile money webhooks are signature-verified and reconciled automatically.

Mifi Core stands today as a complete, working banking suite in beta: ledger, back-office, customer app, mobile money rails, and offline branch support, with compliance workflows (AML alerting, prudential reports, KYC aging) built around COBAC requirements from the start rather than retrofitted. Because a pilot is not yet live, we describe it exactly that way - engineered toward COBAC requirements, and proven in production only once institutions run on it.

A long-cycle in-house build by our engineering team, and the deepest expression of our financial-systems security practice. Development is ongoing through the beta program.