WarsawJS Talk English

The Hidden Battleground: Engineering High-Conversion Payment Experiences

Presented at Meetup #138 Tue, May 12, 2026
Location Cluster Sienna, ul. Sienna 75 (entrance B1, 8th floor), 00-833 Warszawa

About this Talk

For most products, the checkout is the most critical and fragile part of the funnel. It's where traffic turns into revenue, where small UX regressions compound into large financial losses, and where system failures become immediately visible on the balance sheet.

This talk explores how to build resilient, high-converting payment experiences as systems, not screens. Drawing on hundreds of A/B experiments run on tens of millions of users and lessons from operating a global subscription platform generating tens of millions in annual recurring revenue, we'll look at how payment orchestration evolves as products scale across regions, currencies, and providers.

We'll cover how to design checkout UX that converts consistently even for low-frequency products, how to orchestrate multiple gateways without leaking complexity to the user, and how to test and monitor flows where failure tolerance is extremely low. Along the way, I'll even show a shocking example where adding just two form inputs, implemented correctly, could cost over a million dollars in lost revenue.

This is a practical talk from the trenches about why checkout is a hidden battleground, and how resilient payment engineering protects both conversion and growth.

Faris Aziz

Faris Aziz

Staff Frontend Engineer

Faris Aziz is a Staff Frontend Engineer specializing in React, Next.js, monetization systems, and resilient web architecture. He's led teams in early-stage startups and scaling companies, built career ladders from scratch, and shipped systems used by millions. His work spans greenfield builds and legacy refactors across Fintech, SaaS, Fitness, and Connected TV, with companies like Smallpdf, Fiit, Discovery, GCN, and Navro. He focuses on building performant, user-centric applications with solid observability and maintainability. Faris co-organizes ZurichJS, contributes to tools like Raycast, and spends time contemplating life's great questions, like why the build works on his machine but nowhere else.

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