GCASH Office, W Global Center, 9th Ave. cor. 30th St., Bonifacio Global City, Taguig, Metro Manila - February 20, 2025
Ever wondered how top companies streamline development and boost efficiency? Let’s explore how GCash becomes a successful fintech company by optimizing their development through strategic automation, leveraging OpenAPI and WireMock Testing to streamline operations and drive innovation.
The first Java User Group Philippines meetup of 2025 highlighted how Spring is utilized in Application Programming Interfaces (APIs). GCash, serving as the event's venue sponsor, featured expert speakers from their team who shared insights into their best practices for API development and testing.
Speakers
- Lorenzo Dee, Head of Back-end Engineering at GCash, who presented "Effortless Testing with WireMock", discussing strategies for seamless API testing.
- Roy Donasco, AVP, Head of Technical Transformation Delivery at GCash, who spoke about automation in OpenAPI, focusing on optimizing API workflows through automation.
Opening Remarks
Tristan Mahinay, one of the leaders of Java User Group Philippines (JUGPH), welcomed the attendees and provided an introduction to JUGPH, its dedicated volunteers, current sponsors, and past events. He emphasized the expansive Java ecosystem and its thriving community in the Philippines. Additionally, he highlighted the Java Community Process (JCP) Java in Education initiative, which aims to foster Java education and engagement among developers.
Effortless Testing with WireMock
By Lorenzo Dee, Head of Back-end Engineering at GCash
Introduction to WireMock
During the talk, Mr. Lorenzo Dee introduced WireMock as a tool used for mocking and stubbing downstream services in software development and testing. WireMock enables developers to simulate the behavior of real services, APIs, or dependencies that an application interacts with, facilitating efficient testing and debugging.
Understanding Downstream Services
As a supporting explanation, downstream services refer to external or dependent services that an application interacts with to fetch data, process requests, or perform specific functions. These services are typically those that the system calls, rather than services that call the system.
WireMock vs. Traditional Java Class Mocking
Unlike mocking a Java class, WireMock is specifically designed to mock HTTP requests, allowing developers to replicate real API interactions. This is particularly useful when mocking the downstream of an API request, as it enables testing of various scenarios, including failures, slow responses, and unexpected payloads.
WireMock in GCash: Performance Testing
According to Mr. Dee, GCash utilizes WireMock for performance testing, ensuring that the system can handle high traffic and varying response times efficiently. By leveraging mocks, GCash is able to cover various test cases without relying on actual downstream services, thereby enhancing the speed and reliability of its testing process.
Paid vs. Free WireMock
At the end of the talk, an attendee inquired about the differences between the paid and free versions of WireMock. In response, Mr. Dee explained that the paid WireMock is a hosted service, meaning it runs as a managed cloud-based service, eliminating the need for users to set up and maintain their own WireMock instances. This version offers additional features, scalability, and enterprise-level support, making it particularly beneficial for large-scale projects and teams.
OpenAPI Automation
By Mr. Roy Donasco, AVP, Head of Technical Transformation Delivery at GCash
Introduction to API Design-First Approach
Mr. Roy Donasco began his talk by highlighting the API Design-First Framework, an approach that prioritizes defining an API’s structure and behavior before writing any implementation code. This method ensures clear documentation, better collaboration between teams, and a more maintainable development process.
Advantages of an API Design-First Approach
- Clear Documentation
- Design-First Philosophy
- Collaboration and Communication
- Client and Server Development in Parallel
- Automatic Code Generation
- Testing and Mocking
- Contract-First Signing
- Avoids Over-Engineering
- Easier Versioning and Evolution
The Importance of Schema-First Development
Mr. Donasco emphasized that a best practice in API development is to always design the schema first, as it serves as the blueprint for how APIs will function. By defining the schema early, developers can avoid inconsistencies, enhance security, and improve the overall developer experience. A well-structured schema also helps streamline integration, making it easier for frontend and backend teams to work in parallel without misalignment.
Automating API Development with OpenAPI Generator
Mr. Donasco also introduced the OpenAPI Generator, a powerful tool that automates the creation of API client libraries, server stubs, and documentation from an OpenAPI specification. This significantly reduces manual coding efforts, enforces consistency, and accelerates API development.
By leveraging OpenAPI Generator, teams can ensure that their implementations remain aligned with the API specification, ultimately leading to more robust and reliable applications.
Mr. Roy Donasco discussed the OpenAPI approach using the API Generator in Spring Boot. Details about his practical demo are below:
Networking, Raffle, and Closing Ceremonies
The speaker sessions were followed by a raffle featuring computer mice sponsored by GCash and JetBrains licenses provided by JetBrains. Additionally, food was served, generously sponsored by both the venue and GCash, along with networking sessions among the attendees.
Conclusion
The success of the First Java Meetup of 2025 at GCash is a testament to how strategic development and strong community engagement drive innovation. GCash’s seamless approach to automation, leveraging OpenAPI and WireMock, showcases how technology can be optimized to enhance efficiency, scalability, and reliability—critical factors in the ever-evolving fintech industry.
Their commitment to refining best practices in API development not only benefits their internal processes but also sets a high standard for the broader developer community.
Beyond the technical insights, this event underscored the power of tech communities in shaping the future of software engineering. As a Java User Group Philippines (JUGPH) volunteer, I’ve witnessed firsthand how these gatherings create opportunities for collaboration, mentorship, and growth. Events like this inspire developers to push boundaries, share knowledge, and innovate together.
Attending tech meetups is more than just learning about new tools and frameworks—it’s about being part of something bigger. The synergy between industry leaders like GCash and communities like JUGPH is a reminder that technology thrives when we grow together.
Let’s continue to engage, innovate, and drive the future of tech—one meetup at a time.
Take a look at my video coverage below:
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