Modern JavaScript applications rarely fail because of a broken function. They fail at the boundaries: APIs, authentication, feature flags, browser APIs, payments and third-party services.

From a real journey at scale with over 1.3 million transactions, Eduardo will explore an outside-in testing strategy that focuses on what matters most: the interactions between your application and the outside world.

You’ll leave with practical techniques to build confidence, reduce brittle tests and ship changes with greater certainty, regardless of your JavaScript framework.

API contracts are the backbone of modern frontend-backend collaboration, but manual integration slows teams down and increases errors. What if we could automate it?

In this talk, we’ll dive into Shift Left API contract development and introduce an approach to automatically generate an NPM package from API contracts. This package provides:
✅ TypeScript types for strict FE & BE consistency
✅ Zod validation for safer forms and API responses
✅ Axios + React Query for streamlined fetching & caching
✅ Automated versioning & observability to ensure API integrity

By shifting API validation, testing, and integration earlier in development, teams can move faster, reduce errors, and improve efficiency. Whether you're a developer, tech lead, or architect, this session will give you practical strategies to automate your API workflows and accelerate your development pipeline.

API contracts are the backbone of modern frontend-backend collaboration, but manual integration slows teams down and increases errors. What if we could automate it? In this talk, we’ll dive into Shift Left API contract development and introduce an approach to automatically generate an NPM package from API contracts. This package provides:

✅ TypeScript types for strict FE & BE consistency

✅ Zod validation for safer forms and API responses

✅ Axios + React Query for streamlined fetching & caching

✅ Automated versioning & observability to ensure API integrity

By shifting API validation, testing, and integration earlier in development, teams can move faster, reduce errors, and improve efficiency. Whether you're a developer, tech lead, or architect, this session will give you practical strategies to automate your API workflows and accelerate your development pipeline.

Client-side navigation has always been the SPA advantage over server-rendered apps - click a link, see the next page instantly, no round trip. Next.js has been closing that gap piece by piece, and its latest rendering model gets it most of the way there without giving up streaming, caching, or Server Components. This talk breaks down how Next.js decides what's static and what's dynamic at the component level rather than the route level, why that shift is what actually makes instant navigation possible, and what's involved in bringing it into an existing production app.