Features left ColdFusion for React and TypeScript, one at a time.

A client had a production application running on ColdFusion. The job was to move it onto React and TypeScript without taking it out of production, and I was there as a consultant: Lead Consultant, on an engagement that ran from December 2023 to March 2026.

The client is not named on this page, and nothing here identifies them. The engagement had two parts: the port, and a hiring panel.

I sat on the hiring panel, at both of its stages: the pre-screen, and the technical rounds after it. It is the part of this engagement that was not the port — everything else on this page is code.

Two stages, and they are different jobs: the pre-screen decides who reaches a technical round, and the technical rounds are where the engineering is assessed. I sat on both rather than one.

The port ran feature by feature rather than as one replacement: the feature, not the application, is the unit of the migration, and it crosses to React and TypeScript on its own.

On an application that stays in production, that means both stacks are live at the same time — part of it on ColdFusion, part of it on React and TypeScript — and for as long as that is true, the features that have not crossed still have to work.

The engagement ran to March 2026: two years and three months of moving a production application off ColdFusion onto React and TypeScript one feature at a time, and of sitting on the hiring panel alongside it.

Because the client is not named, what usually carries a case study — the name on the door, the industry, the scale — is not on this page. What is here is the shape of the work: a production application, an old stack, and a port that arrived one feature at a time.