Tejas Kumar
Tejas Kumar is an AI Engineer at IBM, based in Berlin, Germany. He is the best selling author of Fluent React (O'Reilly) and the host of the ConTejas Code podcast. He has been building on the web for over 25 years and has given 80 recorded talks at 64 events since 2012. He speaks on AI engineering, agent harnesses, React and the web platform.
Montreal 2027 sessions
How React Really Works Under the Hood
English session - Intermediate
Most React developers use it daily without knowing what happens after they call setState. This talk explains how React works inside: the virtual DOM, Fiber and reconciliation, why components re-render, how concurrent rendering and Suspense schedule work, and what the React Compiler changes. Attendees leave able to reason about performance problems instead of guessing, based on my O'Reilly book Fluent React.
Your Evals Are Lying to You
English session - Intermediate
Passing evals and rising velocity feel like proof that an AI feature works, but both can mislead. This talk explains 4 ways offline evals deceive teams, including an LLM judge that rewards confident wrong answers, then fixes one live with a small rubric change. Attendees learn what to measure instead: traces, production observability, probe-based evaluation, error budgets and quality indicators beside every velocity number.
