Subscription-based software is becoming increasingly popular as more businesses adopt Software as a Service (SaaS) models. However, engineering teams often face challenges when trying to scale their subscription products, especially if they rely on payment systems built on synchronous API polling.
Polling is when a software application repeatedly checks for updates from the payment provider. This method works for a small user base but quickly becomes unsustainable as the number of users grows. Each request from the application adds strain to payment systems, leading to performance issues as transactions increase. This can negatively impact both the business and its customers.
To solve this problem, many SaaS teams are moving away from traditional API polling and adopting event-driven architecture using webhooks. Webhooks reduce strain on payment systems by allowing software applications to receive notifications from the payment provider once a payment is processed. This means the application does not need to constantly check for updates.
As a result, webhooks cut down on unnecessary traffic to payment servers and make payments more reliable for users. They also separate software applications from payment systems, making payment processing smoother as SaaS products grow. With more subscription-based products launching, engineering teams must re-architect their systems to handle events with webhooks. While this approach can be more complex at first, it offers better reliability and flexibility in the long run.
An Engineer Who Has Seen the Transition Firsthand
One engineer who understands this transition well is Kacper Michalik, a software engineer, architect, and product builder with over eight years of experience in developing scalable cloud applications and SaaS products. He began his career in software design, then expanded into full-stack engineering, cloud computing, blockchain, and artificial intelligence (AI).
Working in fast-paced startups has given him insight into how engineering decisions affect product growth, customer experience, and scalability. Michalik is currently co-developing Screen Studio, a macOS screen recording app that topped Product Hunt’s rankings in 2025.
As Screen Studio grew its subscription offerings, Michalik faced many of the same technical challenges as other SaaS companies trying to scale. More customers meant greater strain on the payment infrastructure, highlighting the problems of tightly coupled billing logic and reliability as the platform expanded.
“The standard API integration worked well for low volume, but it tightly coupled billing and application states,” Michalik explained. “Switching to webhooks let us separate those processes, so billing events can be handled independently. This is more resilient, but you must design for idempotency and out-of-order delivery to avoid bigger problems later.”
Throughout the product lifecycle, Michalik has led major architectural improvements and helped launch new features that generate revenue. One of his key achievements was building the Teams feature, which included Stripe-based billing so users could buy and manage team subscriptions.
He also oversaw the move from a standard API integration to a webhook-based Stripe payment system, which improved reliability and made billing easier to scale.
Event-Driven Payment Systems Are the Future
As SaaS businesses grow, more are choosing webhook-based architectures for payment processing instead of traditional polling. Event-driven systems reduce unnecessary API traffic, separate billing from the main application, and help teams build services that can better handle outages and failures. This leads to infrastructure that scales smoothly as customer numbers increase.
Teams planning a similar migration often start with their highest-volume or most critical billing events, like subscription renewals and failed payments. They then move other parts of the integration step by step. This approach limits risk if issues arise and lets teams test the new architecture along the way.
Implementing webhook-based systems takes careful planning. Engineers need to handle challenges like idempotency and out-of-order event delivery to make sure billing is always processed correctly. Dealing with these issues early helps build strong and maintainable payment systems.
AI Is Accelerating Modern Software Engineering
AI is also changing modern software engineering. Engineers now use AI tools to research, write prototype code, find bugs, and test ideas much faster than before. Still, the industry needs skilled engineers like Michalik to create new solutions and ensure strong technical foundations.
“AI has made coding, research, and debugging much quicker,” said Michalik. “But it hasn’t replaced the basics. You still need to understand architecture, design patterns, and performance trade-offs to build lasting systems. AI speeds things up, but you still have to think through the hard parts.”
AI is also changing entrepreneurship by making it cheaper and faster to test new product ideas.
“AI really helps when testing startup ideas,” Michalik said. “Building a prototype or MVP that once took weeks can now be done in days. That means you can test ideas much sooner and at a lower cost.”
For startups with limited budgets, getting quick feedback on prototypes helps improve decision-making and speeds up development.
Final Thoughts
The move from polling to webhooks is more than just a technical choice. It reflects the growing need for scalable, reliable, and flexible payment systems in modern SaaS apps. As subscription businesses grow, teams that use event-driven architecture will be better able to support growth and keep customers happy.
While AI speeds up software development, sound engineering fundamentals are still essential. Building scalable systems requires smart architectural choices, and webhook-based payment processing is one such choice that brings long-term benefits to SaaS businesses.
