AJILEYE BOLUWATIFE ISAACSenior Backend Engineer
Profile summary

Senior Backend Engineer and Technical Lead with 7+ years of experience building large-scale, distributed systems across payments and telecom platforms serving millions of users. Specialized in ledger-based financial systems, high-throughput payment processing, and API platforms with strong guarantees around correctness, idempotency, and fault tolerance. Hands-on expertise in Java (Spring Boot), PHP(Laravel) event-driven architectures, cloud-native infrastructure, and deep observability (OpenTelemetry). Proven delivery of multi-currency, compliance-aware payment flows, secure APIs, and resilient data models under high traffic. Known for leading teams, raising engineering standards, and shipping production systems that scale reliably in regulated environments.

SKILLS / Technology stack
Java
Spring Boot
PHP
Laravel
GIT
MySQL
PostgreSQL
KeyCloak
MongoDB
Redis
Linux
Maven
Apache Kafka
RabbitMQ
Docker
Kubernetes
CI/CD
ISO
Socket Programming
Kannel
Smpp Communication
Work Experience

TEAM LEAD (BACKEND ENGINEERING TEAM)

MTN COMMUNICATIONS NIGERIA⁠
Jan 2025 – present | Lagos, Nigeria
  • •Actively contributing to myMTN App and it's Dxl microservices architecture.
  • •Optimized backend services for performance, reliability, and scalability across high-traffic telecom platforms.
  • •Implemented OpenTelemetry (OTEL) logging and tracing in collaboration with DevOps team to enable concise monitoring for OpenShift services, serving as an alternative to Azure Application Insights.
  • •Built and maintained key product features including FibreX, Loyalty Bundles, and other customer-facing service integrations.
  • •Developed and supported an API monetization platform, enabling per-call billing and controlled access for external and internal API consumers.
  • •Integrated headless NPG payment flows for MTN Play, supporting multiple payment channels such as cards, bank transfers, MoMo, and other payment methods.
  • •Designed and implemented a push notification aggregation service, consolidating Google Cloud Messaging (GCM/​FCM) and routing notifications across multiple application channels.

    • SENIOR BACKEND ENGINEER (CONSULTANT)

    Duplo Inc. (YC 22)⁠
    Apr 2025 – present | Lagos, Nigeria
  • •Architected and delivered enterprise-grade, multi-currency payments infrastructure (NGN, KES), supporting bank transfers, mobile money, paybill, and checkout orchestration with country-specific compliance controls (e.g., Nigeria stamp-duty automation).
  • •Designed ledger-centric transaction processing systems with full financial integrity guarantees, accurately handling credits, debits, fees, reversals, negative balances, and parent-child transaction relationships at scale.
  • •Implemented cryptographically secure API payload encryption using AES-256-GCM and per-merchant keys, enabling cross-language interoperability and secure client-side encryption (Postman, backend services, third-party integrators).
  • •Built high-throughput, fault-tolerant asynchronous workflows using queued jobs, retries, idempotency keys, and event-driven webhooks to reliably process inflow and payout lifecycles.
  • •Optimized PostgreSQL financial data models and queries, leveraging enums, JSONB metadata, and precision-safe numeric operations to power real-time balance calculations, reconciliation, and reporting.
  • •Delivered production-ready APIs with strict validation, adaptive rate-limiting, observability (request duration, metrics, structured logging), and clean resource representations aligned with payments and fintech best practices.

    • SENIOR BACKEND DEVELOPER

    TM30 GLOBAL LIMITED⁠
    Mar 2023 – Dec 2024 | Lagos, Nigeria
  • •Played a key role in the development of payment solutions for POS terminals, using ISO8583 and core POS communication Standards and Encryption protocols.
  • •Coordinated the development of features and deployment of backend systems for an Enterprise short messaging platform using KANNEL as sms gateway integrating to all nigerian TELCOS.
  • •Designing and implementing robust backend architectures, leveraging Java (Spring Boot) for a Payment Gateway software system ensuring compliance with industry standards such as PCI DSS..
  • •Utilized containers and modern software engineering practices such as Domain-Driven Design (DDD) and Test-Driven Development (TDD) to streamline development processes and enhance system scalability and availability.
  • •Manage the optimization and adding of key features to an investment technological solution which resulted in increase in user acceptance
  • •Employed various caching and messaging protocols to improve system performance and communication like Redis, RabbitMq, Kafka.
  • •Maintained comprehensive documentation for knowledge sharing and onboarding of team members.

    • Lead Backend Engineer

    OnePurse co.
    Jan 2024 – Oct 2024(Remote) Colorado, USA
  • •Lead the design and implementation of backend architecture using Java (Spring Boot) to craft scalable, high-performance solutions for a large-scale grocery ecommerce platform.
  • •Oversee data management and optimization with PostgreSQL, MySQL, and MongoDB, including designing complex database schemas and optimizing queries for performance.
  • •Implement performance enhancement techniques, such as caching strategies, asynchronous processing, and efficient load balancing, to handle high user interactions and ensure swift response times.
  • •Handle deployment using Docker and Linux-based servers, managing CI/​CD pipelines to automate testing, builds, and deployments, enhancing development efficiency.
  • •Utilize Git for version control, facilitating smooth collaboration and code management, and maintain CI/​CD pipelines for streamlined code quality and deployment.
  • •Collaborate with cross-functional teams, including product managers and frontend developers, to ensure backend solutions meet business objectives and user requirements.
  • •Mentor junior developers, participate in code reviews, and maintain detailed technical documentation for system designs, API specifications, and user guides.
  • •Implement robust security protocols to protect sensitive data and ensure regulatory compliance, identifying and mitigating potential vulnerabilities.
  • •Proactively identify and resolve technical issues, optimizing system performance and ensuring backend reliability.

    • Backend Developer

    Fabany Consulting Limited
    Sep 2020 – Feb 2023 | Lagos, Nigeria
  • •Contributed to designing and implementing server-side logic for web applications and websites, ensuring seamless backend functionality.
  • •Assisted in writing, testing, and debugging code, focusing on delivering clean and maintainable solutions.
  • •Collaborated closely with front-end developers to integrate backend systems with the user-facing side, ensuring smooth, user-friendly application experiences.
  • •Worked with both relational and non-relational databases to manage data storage, ensuring secure and efficient access to data.
  • •Implemented security measures to protect sensitive data and systems, adhering to best practices and organizational security protocols.
  • •Optimized backend performance, ensuring systems could handle high traffic and large amounts of data by incorporating caching and queuing features.
  • •Maintained and updated existing backend systems, providing continuous improvements and support to meet evolving business needs.
  • •Actively participated in code reviews and team meetings, learning from senior developers and contributing to collaborative problem-solving and decision-making processes.

    • Backend Developer (Intern)

    HOTELS.NG⁠
    Remote, Nigeria
  • •Maintained clear and effective communication with the project manager and team to ensure alignment on project goals and timelines.
  • •Worked closely with front-end developers to seamlessly integrate backend APIs with the user interface, enhancing the overall user experience.
  • •Designed and implemented server-side logic for web applications, leveraging the Laravel framework to ensure robust and scalable solutions.
  • •Applied software engineering expertise to translate product requirements into well-defined technical tasks, contributing to efficient product development.
  • •Developed and optimized database schema and migrations using Eloquent ORM, ensuring smooth data handling and system performance.
  • •Finished all modules of the internship and got to the final stage and was certified.
    • Major Projects

    MTN Nigeria Architecture & Engineering

    Actively contributing to the development and enhancement of several MTN Nigeria digital platforms, including the myMTNApp, Notification Aggregator Services, and other high-impact consumer and backend-facing applications. My work spans across building scalable backend systems, optimizing performance, integrating third-party services, and ensuring secure, reliable user experiences for millions of customers nationwide.

    Payment Gateway

    Card payment processing solution

    Developed Microservice architectural design for the User management and payment processor service.

    Developing the payment processor gateway using UPSL payment Interface (Cipa) as well as ISO8583 card processing messaging to payment processor to facilitate card transactions between the Merchant Acquirer and Card Issuer.

    Implemented strong card tokenization using ISO interfaces for managing managing token BINs and BIN ranges.

    Designed and developed strong fraud detection modules to track incosistencies in transactions flow

    Enterprise Short Messaging Platfrom

    Implementated Short messaging standards and encryption protocols to allow SMS communication via smpp to kannel and sms gateway.

    Developed downtime monitoring features to reduce the impact of downtime as the application serves major nigerian banking institution as sms delivery solution

    Improve codebase to reduce request time from the sms partnerr to the telecommunications service partner via their smpp gateway

    Developed middleware to optimize continous accessibility for varios traffic situations from high and low traffic clients.

    Improved system reliability by load balancing the core sms processing platform to allow high volumn traffic

    Education

    Bachelor of Science.

    University of Ibadan
    Feb 2017 – Dec 2021 | Ibadan, Nigeria