Why Node & NestJS

The server behind the app

In the iOS course you built the PawWalk app. Every screen — the walker list, the booking form, login — worked by asking a server for data over HTTP. This course builds that server in TypeScript on Node.js, using NestJS: the other side of the URL. (Never written Node? Perfect — this course assumes zero backend experience and explains as it goes.)

Node.js runs JavaScript/TypeScript outside the browser on a single-threaded, event-driven, non-blocking I/O model — one thread juggling thousands of connections by never sitting idle waiting on the network or disk. NestJS is the framework on top: it gives that runtime real structure — modules, dependency injection, decorators — the kind of scaffolding a team needs so a codebase stays maintainable past its first ten files.