The “Secret Sauce”: What Makes a NextGen Application Services Tech Lead Unique?

An Interview with Will Li, Tech Lead, Application Services

Continuing our series on what working life is like at NextGen, we sat down with Will, a Tech Lead in Application Services, to discuss some of the aspects in his role you might not normally hear about in the secret sauce of his role.

Q: You own the technical health of a platform that has led the home loan origination market for 30 years. How do you approach the challenge of maintaining technical precision within a mature codebase while simultaneously delivering the transition to next tier technologies? 

Will: The key for us is stability and preferring an incremental approach instead of rewriting everything at once. Because our product is so mature, stability is a huge part of why customers use our system, so we have to be very careful not to break what works well.

It is about thought rigour and maturity in our engineering. We do not just start refactoring technical debt. We run through discussions and formalise the process to deeply understand the existing dependencies.

In practice, we use methods like feature flags, a switch that keeps the existing functions working while we roll out new features. When we transition, we use small-scale testing, taking a broker centre instance as a pilot, a “test bat”, to ensure the new code works before we roll it out to everyone

Q: In Application Services, execution speed is critical when a customer issue arises. How do you navigate the tension between delivering an immediate fix and maintaining long term technical excellence?

Will: The first priority is always to restore the service and reduce customer impact as fast as possible. Sometimes this means putting in a small, safe, temporary workaround or production patch.

However, we do not leave that temporary fix sitting around to become technical debt. Once things are stable, we immediately loop back. We conduct a PPR (post-production review) with stakeholders, such as architects and other Tech Leads to investigate the root cause, determine preventative measures, and raise a follow-up task to implement a robust, long term fix. We are constantly finding the best of both worlds: speed for the customer and quality for the long term.

Q: Many engineers prefer “green field” work. What are the unique rewards of getting into a complex, multi-layered codebase that is a dominant market leader?

Will: I enjoy the social aspect, collaborating with people from different departments and expertise, which is necessary because the system is so complex. NextGen has a very helpful culture.

On the technical side, it is about solving a puzzle. Because the codebase includes a complex, multi-technology ecosystem, every problem requires using your brain properly and being a problem solver from the outset. It requires creativity about solutions because there are always multiple ways to fix an issue, and our decision making is critical because it has a long term impact.

The achievement is refactoring an older piece of code, making it newer and more elegant. You get the same sense of accomplishment as green field work, but from a standing point of already having thousands of customers using and relying on the solution.

Q: When things are critical, how do you balance being a leader (a “multiplier”) versus getting hands-on?

Will: Normally, I try to lead and enable the team to uncover solutions, but if there is a critical customer impact, I will also get a lot more hands-on and dive into the investigation, workaround, fix, testing, and release process as each of us contributes to our overall success.

The most unique part is our customer-first focus. Even if a mistake was made by another team, my goal is to reduce the customer impact, and I take responsibility for that customer rather than debating which team owns what.

My perspective on this changed after speaking with colleagues who were former mortgage brokers, which gave me a much better understanding of their high-stakes work, where time truly is money. A seemingly small technical issue on our side may   force them to stop immediately  and can lead to them losing the loan and the customer they worked hard to win. Because of this real-world impact, I always treat broker issues with a sense of urgency and do my best to resolve them quickly.

While I get involved, I rely on the Business Analyst (BA) to handle the communication loop with the customer, as they have more experience. But I make sure the BA is aware of the technical decisions so they can maintain the context for the customer.
Success at NextGen is built on a blend of technical rigour, customer-first leadership, and the unique satisfaction that comes from solving deep, complex puzzles within a market leading product. If Will’s insights have made you curious to learn more about the people who make NextGen operate, you can read more from our careers blog to find other profiles and stories, or join our online community to learn more about what is going on at NextGen and connect directly with our teams.