Lead Software Engineer · Robi Axiata
Eight years on telecom billing, mobile financial services and utility platforms — the kind of software where a dropped message means someone is not billed, or is billed twice. Currently leading a team of four on a pipeline that generates around two million invoices per cycle.
Most of this work is under NDA, so there are no screenshots or repositories here. What there is instead: the architecture, the decisions, and the alternatives I turned down.
Event-driven postpaid billing at national scale
A chain of Spring Boot services that turns bulk billing XML into ~2 million customer invoices per cycle — parsed, priced, rendered to PDF and delivered — where a single dropped message means someone does not get billed.
An MFS and payment-service platform decomposed into ~32 services
A digital wallet and payment-service platform built as a genuine microservice estate — wallet, payments, cash-out, merchant, KYC, loyalty, ISO 8583 card rails — with Apache Fineract as the core banking system underneath it.
A mobile banking core on Cyclos 3, and the agent hierarchy above it
The bank's mobile financial services product: a Cyclos-based core where every customer, agent, distributor and merchant is a wallet, and a single cash-in decomposes into a principal transaction plus its fee and commission children.
ECDH key agreement, encrypted payloads, and a reactive trust boundary
A reactive API gateway built from nothing in front of subscriber verification services — elliptic-curve key exchange per client, AES-GCM encrypted request bodies, HMAC-signed and timestamped handshakes, and JWT identity, all decided in one place.
One system, three state utilities, and the full life of a gas connection
The billing and revenue platform used by three of Bangladesh’s state-owned gas distribution companies — customers, meters, bills, disconnections, vigilance and litigation, in one long-lived system.
The worst production failure I have owned did not throw. A Kafka producer stalled silently and a billing run simply stopped. Anything that can hang needs a clock on it, so an invisible wedge becomes a loud, catchable failure.
A boolean tells you where something is. It cannot tell you how it got there or who authorised it. In billing, ledgers and utility connections, that history is the part auditors, courts and customers actually ask about.
Six services drifting apart on message shape is how an event-driven system rots quietly. One shared library owning topic names, encoding and DTOs turns a breaking change into a compile error instead of a 3am incident.
Reactive where the work is I/O and back-pressure is real. A monolith where one team shares one database. Complexity is a budget — spend it where the problem is, and be able to say why you did not spend it elsewhere.
Things I have shipped and operated in production — not a list of everything I have read about.