Fernando – Golang, Golang REST API, Spring Boot

A customer prequalification platform for retail lending that helps stores assess new and existing customers and support credit loan decisions. The product evaluates credit status, ranks customers based on risk profiles, and enables retailers to offer suitable payment plans and loan amounts through a centralized decision-making process.

• Integrated with third-party credit systems to retrieve customer data, credit scores, and calculate appropriate loan amounts to grant;
• Simplified integrations with digital channels by exposing business logic through a universal, country-agnostic, centralized API;
• Designed error validation and handling for edge cases and operational scenarios, applying design patterns to ensure high availability and throughput during peak usage;
• Instrumented tracing and logging across microservices, improving production issue detection, identifying bottlenecks, and supporting mitigation, testing, and future-proofing of error scenarios.

A microservices-based payment gateway that enables customers to make payments on loans and other financial products through web and mobile channels via a centralized API. The platform supports asynchronous transaction processing to improve user experience and reduce wait times while maintaining consistency and reliability across distributed systems operating at scale.

• Led the implementation of a high-traffic payment microservice operating across more than 30 countries, enabling customers to repay existing loans through digital channels and receive transaction status notifications;
• Deployed a webhook API endpoint secured with OAuth authentication to receive status updates for customer transactions;
• Increased transaction visibility and transparency for customer operations;
• Implemented idempotency protocols, eliminating the risk of duplicate transactions and payments in flows where requests could be submitted more than once.

A centralized notification gateway that enables customers to receive transaction-related updates through their preferred communication channels, including SMS, email, and push notifications. The platform provides a unified set of asynchronous APIs that allow digital applications to deliver timely and reliable notifications across multiple countries and messaging providers.

• Led the launch of a multi-country notification service, enabling internal web and mobile applications to send customers updates related to credit transactions and requests, such as loan repayments and new credit applications;
• Integrated Google Cloud Pub/Sub SDK into existing Golang and Java microservices, enabling vendor transaction notifications to be published asynchronously and consumed by internal applications through subscription-based workflows;
• Integrated messaging providers, including Twilio, Mandrill, and Firebase, to deliver notifications through customers’ preferred communication channels.

A high-performance service communication initiative focused on replacing REST and JSON-based interactions with gRPC and Protocol Buffers across payment microservices. The solution improved service-to-service communication efficiency, reduced latency and infrastructure overhead, and enabled more scalable processing of high-volume payment transactions.

• Identified and implemented all required Protocol Buffer message definitions for microservice communication, generating server and client code to efficiently exchange data;
• Reduced response times by more than 40% by eliminating the overhead associated with traditional HTTP-based service communication;
• Increased API gateway throughput, enabling the platform to process a higher volume of requests within the same time frame;
• Leveraged strongly typed message contracts and communication protocols to reduce validation logic in business code and improve code readability, contributing to more than 30% faster development cycles.