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Okechukwu Diei

@okechukwudiei

Message

Senior backend engineer building high-throughput payment and banking APIs across Africa.

Nigeria

Message

What I'm looking for

I want to build and scale backend APIs for payment and remittance platforms—high-throughput transaction systems, event-driven microservices, and bank/card scheme integrations—working with teams that value reliability, compliance, and measurable delivery.

I’m a Senior Backend Software Engineer with 5+ years building payment gateways, remittance, and digital banking APIs across Nigeria and Southern/East Africa. I specialize in high-throughput transaction systems, card payments, mobile money, and cross-border payouts, with a focus on reliable bank and scheme integrations.

In my most recent role at Interswitch Group Limited, I lead backend API development for Quickteller Mobility—enabling ride-hailing and transport payments, driver settlements, and wallet top-ups. I also design event-driven microservices with Kafka and AWS SQS/SNS for asynchronous settlement and reconciliation, and I built Relayr’s Merchant Operating System in Rust.

Previously, I delivered NIBSS integration work at Prospa Microfinance Bank, and built card payment microservices at Cellulant with tokenization, 3DS, multi-acquirer routing, and CyberSource integration across multiple African markets. Earlier, at SeerBit, I developed recurring payment APIs and cross-border payout engines (including Visa Direct Pay) while building an idiomatic Go SDK for merchant integrations.

Experience

Work history, roles, and key accomplishments

Current

Senior Software Engineer

Current

Interswitch Group Limited

May 2025 - Present (1 year 1 month)

Led backend API development for Quickteller Mobility, enabling ride-hailing and transport payments, driver settlements, and wallet top-ups. Designed event-driven microservices with Kafka and AWS SQS/SNS for asynchronous settlement and reconciliation, and built a Rust-based Relayr merchant operating system for inventory sync, order orchestration, fulfillment tracking, and analytics while supporting

Backend Development Microservices Event Driven Architecture Apache Kafka Rust PostgreSQL PCI DSS

Senior Software Engineer

Prospa Microfinance Bank

Jan 2025 - Apr 2025 (3 months)

Delivered NIBSS integration for a digital banking backend API to enable instant transfers and account validation. Improved reliability and observability with structured logging and distributed tracing, and aligned message formats and reconciliation logic with the core banking vendor.

NIBSS Integration Message Format Mapping

Senior Software Engineer

Cellulant

Mar 2022 - Dec 2024 (2 years 9 months)

Built card payment microservices supporting tokenization, 3DS, and multi-acquirer routing. Integrated CyberSource, Revio Pay, Peach Payments, and MPGS, optimized authorization flows, and delivered mobile money APIs across Tanzania, Zambia, Kenya, and Ghana via Nsano Mobile Money.

Java Spring Boot Card Payment Microservices Tokenization 3DS CyberSource API MPGS

Senior Software Engineer

SeerBit

Aug 2019 - Feb 2022 (2 years 6 months)

Developed a recurring payment API for subscription billing for merchants and implemented CyberSource card payment flows for auth, capture, void, and refund. Built a Go SDK for merchant integrations with retry logic and webhook verification, and delivered cross-border digital payout/remittance APIs including Visa Direct and multi-currency FX support with idempotent transfers.

Go Payment Integration CyberSource Payments Retry Logic Visa Direct Multi Currency FX Quoting Idempotent Transfers

Junior Software Developer

KSmart Solutions

Jun 2018 - Jul 2019 (1 year 1 month)

Built REST APIs for SME business applications using Java Spring Boot and PostgreSQL. Implemented background job processing with RabbitMQ and supported API documentation and code reviews.

Java Spring Boot REST APIs PostgreSQL RabbitMQ Background Jobs API Documentation Code Review