Invite me to speak

I speak about TypeScript performance, the TypeScript compiler and AI agents built in TypeScript. Talks, workshops, podcasts and meetups, in English or French, on site or online.

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Short bio

I'm a TypeScript developer focused on type-checking performance and TypeScript 7. I measure what makes TypeScript slow, then fix it: I run a public TypeScript Performance Lab with reproducible experiments, and my fixes to TypeScript's DOM types have been merged into Microsoft's TypeScript-DOM-lib-generator. I'm Lead Content Owner for the JavaScript and TypeScript certifications at Certificates.dev, and I've spent seven years building large-scale enterprise applications with TypeScript, Angular and Spring Boot. I also host What's up TypeScript France, an online TypeScript meetup.

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Talks

Talks you can book

Each one can run as a talk, online or on site, in English or French.

  • The DOM Is Lying to Your Types

    Level
    Expert
    Format
    30 to 45 min

    Every TypeScript project trusts lib.dom.d.ts, but it isn't written by hand: a generator turns web specifications into types, and that translation is where bugs hide. Optional parameters that throw, iterables typed as arrays, return types lost on the way. I fix these bugs upstream in Microsoft's generator. In this talk, I show how WebIDL becomes TypeScript, why the spec and not MDN is the source of truth, how to prove a DOM type is wrong, and how a fix travels from a pull request to your editor.

  • Your Types Have a Performance Budget. You're Just Not Measuring It.

    Level
    Expert
    Format
    30 to 45 min, also as a half-day workshop

    A one-line type change can multiply type-checking cost by ten without breaking a test: real projects shipped 23 times more instantiations and CI jobs that crashed. We budget bundle size and page speed, so why not types? The compiler's counters are deterministic: same code, same numbers on any machine, perfect for a CI gate. I show how to measure the cost of your types, find the generic that dominates it, and fail a pull request before your build slows down.

  • Your AI Agent Is Slowing Down Your Compiler

    Level
    Intermediate to expert
    Format
    30 to 45 min

    Typed AI agents are everywhere: tools described with schemas, structured outputs inferred into TypeScript types, SDKs built on deeply generic APIs. Great for safety, but they can quietly crush your type-checker. I'm measuring what schemas, tool definitions and AI SDK types cost the TypeScript compiler as an agent grows from 1 to 50 tools, and which ways of writing them stay fast. You'll see the numbers, why some patterns explode, and how to keep agents fully typed and fast to build.

Past talks

Delivered, newest first.

All speaking
  • WorkshopDelivered

    Pizzeria del Compilator: Building a Type-Safe Configurator with TypeScript

    Speaker, Frontend Nation 2026, TypeScript Day, October 20, 2026, online

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Or write to mferret.pro@gmail.com