Frontend
React, Next.js, TypeScript, Tailwind CSS. Component-driven interfaces with server-side rendering where performance demands it.
ReactNext.jsTypeScript
About
A web development practice built on precision, not shortcuts.
Gessli Dev is a Paris-based web development practice run by Konstantin Gessli, building custom websites, web applications, and digital products for businesses that expect things done properly.
What we believe
Most web development problems are not technical — they are process problems. Scope that was never clearly defined. Architecture decisions made on the fly. A handover that never happened. The way a project is managed matters as much as the code that gets written.
How we work
We define scope precisely before starting. We document what we build as we build it. We test on real devices and browsers. We hand over working, documented code the next developer can actually understand — with no dependency on us to keep it running.
Our stack
Modern, stable technologies. No chasing trends.
Technologies with a proven track record and a clear future — a codebase you can maintain, extend, and hand to another developer without a manual.
Backend & Data
Node.js, PostgreSQL. Clean API design with proper error handling, logging, and security built in from the start.
Node.jsPostgreSQL
Infrastructure
AWS, Vercel. Automated deployments with CI/CD pipelines and monitoring set up before go-live.
AWSVercel