Part I — The Pipes
1 Networking
GoalUnderstand how bytes travel from a server to a pixel, and pick the right API style.
- 1.1 Important Guidelines Watch, then redraw the diagram from memory, then build it — three passes or it does not stick.
- 1.2 Why Networking Matters Most of a page load is waiting, not computing — so most of your wins live in the network.
- 1.3 How the Web Works URL → DNS → TCP → TLS → HTTP → parse → render: six hops, each with a cache in front of it.
- 1.4 Communication Protocols HTTP/1.1 queues, HTTP/2 multiplexes over one TCP stream, HTTP/3 removes TCP's shared queue entirely.
- 1.5 REST APIs Nouns as URLs, verbs as methods, state in the response — and every call stands alone.
- 1.6 GraphQL One endpoint, one round trip, and the client declares exactly which fields it needs.
- 1.7 gRPC Binary contracts over HTTP/2 — call a remote function like a local one, in a fraction of the bytes.
- 1.8 Choosing: REST vs GraphQL vs gRPC Pick by who the clients are and how nested the data is — not by what's newest.
Capstone
Draw the full network path for loading an Instagram post, with every cache hit marked.