Olayinka Huzain Sulaiman

Senior Java backend engineer with 6+ years delivering high-performance financial and enterprise systems. Built and integrated payment infrastructure using ISO 8583 and ISO 20022 switching. Developed backend services with Spring Boot, Spring Security, Hibernate/JPA, and SQL; integrated distributed messaging with Kafka and RabbitMQ.

• Payment & Card Integration Platform, Java, Spring Boot, Mastercard, Visa, Dinero, Tap, Stripe, Payment APIs, Designed and implemented card-payment integrations supporting PCI and non-PCI card-processing environments. Integrated Mastercard, Visa, Dinero, Tap, and Stripe into backend payment-processing flows. Developed backend services for card transaction processing, validation, payment orchestration, and provider communication.
• ISO 8583 Payment Switching & Transaction Processing, Java, Spring Boot, ISO 8583, ISO 20022, NIP, Kafka, RabbitMQ, Developed and integrated ISO 8583 transaction-processing and payment-switching workflows. Implemented transaction routing, request/response processing, banking integrations, and resilient failure-handling patterns. Developed and supported NIP gateway processing for real-time interbank transactions. Contributed to modernization of payment rails toward ISO 20022.
• AWS to Huawei Cloud Migration - Zero Downtime, AWS, Huawei Cloud, Kubernetes, Docker, Java, Spring Boot, Designed and executed migration of production workloads from AWS to Huawei Cloud without service downtime. Planned infrastructure dependencies, application configuration, deployment strategy, and traffic transition. Validated application health, connectivity, functionality, and data consistency throughout the migration. Supported containerized workloads using Kubernetes and Docker.
• High-Efficiency Cross-Database Migration Platform, Java, Spring Boot, PostgreSQL, MySQL, MSSQL, Oracle, MongoDB, Designed and developed a high-efficiency application for migrating large volumes of data across heterogeneous databases. Implemented configurable extraction, transformation, validation, and loading workflows. Used efficient batch-processing strategies to improve migration throughput. Optimized database operations and resource consumption while maintaining data integrity and failure handling.
• Distributed Financial Transaction Platform, Java, Spring Boot, Kafka, AWS SQS, Redis, Kubernetes, AWS, Migrated financial transaction operations toward distributed services with loose coupling and asynchronous processing. Implemented payment gateway routing, POS switching integrations, transaction recovery, retry/backoff, and locking strategies. Supported maker-checker controls and resilient transaction processing.

• 6+ years of professional software engineering experience, with a strong Java/Spring Boot background.
• Hands-on ISO 8583 payment processing and switching experience.
• Direct experience integrating Mastercard and Visa payment services.
• Experience with NIP, banking integrations, POS switching, payment gateways, and card processing.
• Strong understanding of TCP/IP, socket programming, WebSocket, asynchronous messaging, and distributed systems.
• Experience building resilient transaction systems using Kafka, RabbitMQ, Redis, retry, backoff, locking, and recovery mechanisms.
• Production cloud experience across AWS, Azure, and Huawei Cloud, including a zero-downtime cloud migration.
• Strong database and data engineering experience across relational and NoSQL platforms.