Graduation

Look how far you came

You started this course never having written a line of backend TypeScript, knowing only that the PawWalk app from Part I asked a server for data. You are now the person who builds that server.

Retrace the climb:

• The language & the runtime (00–03) — TypeScript for the backend, async/await and the event loop, modules and npm. You learned why Node handles thousands of connections on one thread — and why blocking that thread is the cardinal sin.
• HTTP, then Nest (04–06) — a raw node:http server, then NestJS: modules, controllers, providers, dependency injection, DTOs and validation. The three building blocks that make every resource look the same.
• The real PawWalk backend (07–11) — Prisma and a database, the walkers API, JWT auth, bookings with transactions priced in cents, and streams + a job queue.
• Prove it & ship it (12–13) — testing with Jest and Supertest, then hardening (helmet, CORS, throttler), fail-fast config, graceful shutdown, health checks, and a multi-stage Docker image.