I led the technical design and development of a complete rebuild of Postscript's popup editor, replacing a legacy tool that had become a significant customer pain point. The original editor had been in use since the company's founding and had scaled far beyond its intended capacity—its extremely limited feature set made anything beyond basic customization nearly impossible, forcing customers to pay for third-party popup solutions. This resulted in churn and lost deals. The technical challenge was clear: we needed a modern, flexible tool that would maintain the performance standards critical to our SDK, which was being loaded hundreds of millions of times per month on our customers' Shopify sites. I began by prototyping different rendering technologies on my own time to navigate known technical constraints. Our SDK needed to remain lightweight to avoid degrading site performance, which meant minimizing bundle size while maximizing configurability. After testing both Lit and a React/Preact dual pipeline approach, I validated that Lit would meet our needs without unnecessary complexity. With the rendering backend decided, I designed the underlying data structures for popup representation, drawing inspiration from Notion's block architecture. I wanted to create an arbitrarily composable system using block-like primitives that would map to HTML elements—headers, form inputs, media—while remaining efficient to transmit and render. After about a month of experimentation, I validated that the system could support complete configurability without sacrificing performance. The most critical design challenge was abstracting the complexity of HTML and CSS into intuitive, user-friendly controls that didn't require customers to learn web development to create effective popups. Once the project was sufficiently de-risked, additional team members were brought on, and I continued building large portions of the rendering code while overseeing the editor's development. I served as the primary interface with Product and Design throughout the project, ensuring all stakeholders remained aligned. The results were significant: in the first full quarter after releasing to early customers, we saw a 2x increase in opt-in rates and a measurable jump in GMV adoption. Because our popups serve as the top of Postscript's subscriber funnel, we leveraged existing analytics pipelines to gain full visibility into these improvements. The new editor eliminated the need for third-party solutions, reduced customer churn, and dramatically expanded the customization capabilities available to Postscript's customers. Some data: Increased aggregate opt-in rate by 2x, going from ~2% to ~4% on the new editor. Increased adoption of PS popups from ~45% of merchant GMV to ~70% of merchant GMV.