Freedom Dumlao: What 70 Java Services Taught Me About Focus

Freedom Dumlao (CTO at Vestmark ) joins Robby to explore what it means to maintain software at scale—and why teams sometimes need to unlearn the hype. With two decades of experience supporting financial systems, Freedom shares how his team manages a Java monolith that oversees $1.6 trillion in assets. But what’s most surprising? His story of how a team working on 70+ microservices rebuilt their platform as a single Ruby on Rails monolith—and started shipping faster than ever before. Episode Highlights [00:02:00] Why Respecting Legacy Code Matters Freedom reflects on a lesson he learned at Amazon: "Respect what came before." He discusses the value of honoring the decisions of past developers—especially when their context is unknown. [00:05:00] How Tests Help (and Where They Don’t) Freedom discusses how tests can clarify system behavior but not always intent—especially when market logic or business-specific rules come into play. [00:07:00] The Value of Understudies in Engineering Freedom shares how his team intentionally pairs subject matter experts with understudies to reduce risk and transfer knowledge. [00:09:30] Rethinking Technical Debt He challenges the fear-based framing of technical debt, comparing it instead to a strategic mortgage. [00:17:00] From 70 Services to 1 Monolith At FlexCar, Freedom led an unconventional rewrite—consolidating 70 Java microservices into a single Rails app. The result? A dramatic increase in velocity and ownership. [00:25:00] Choosing Rails Over Phoenix, Laravel, and Django After evaluating multiple frameworks, Rails' cohesiveness, Hotwire, and quick developer ramp-up made it the clear winner—even converting skeptical team members. [00:31:00] How Rails Changed Team Dynamics By reducing dependency handoffs, the new Rails app enabled solo engineers to own complete features. The impact? Faster delivery and more engaged developers. [00:36:30] Why Rails Still Makes Sense at a 20-Year-Old Company Even with a large Java codebase, Vestmark uses Rails for rapid prototyping and new product development. [00:41:00] Using AI to Navigate Legacy Systems Freedom explains how his team uses retrieval-augmented generation (RAG) to surface relevant code—but also the limitations of AI on older or less common codebases. [00:51:00] Seek Feedback, Not Consensus Freedom explains why aiming for alignment slows teams down—and how decision-makers can be inclusive without waiting for full agreement. Links and Resources Freedom Dumlao on LinkedIn Vestmark No Rules Rules Dungeon Crawler Carl series Thanks to Our Sponsor! Turn hours of debugging into just minutes! AppSignal is a performance monitoring and error-tracking tool designed for Ruby, Elixir, Python, Node.js, Javascript, and other frameworks. It offers six powerful features with one simple interface, providing developers with real-time insights into the performance and health of web applications. Keep your coding cool and error-free, one line at a time! Use the code maintainable to get a 10% discount for your first year. Check them out!

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Freedom Dumlao: What 70 Java Services Taught Me About Focus is an episode from Maintainable by Robby Russell.

This episode is 01:03:19 long.

This episode was published on Apr 22, 2025.

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