# HTTP, JSON, APIs & Streaming

**Track:** The Full-Stack Substrate — AI-Native Full-Stack Development — complete (30)
**Framework / surface:** web dev (HTTP / Fetch / Streams)
**Level:** Intermediate
**Prerequisites:** Server/Client Boundaries & Routing, TypeScript for AI-Native Builders

**In one line:** Requests and responses are the connective tissue of the web — including when the response arrives a piece at a time.

## Theory, aesthetics & inspiration

HTTP is the protocol under everything in this course — pages, JSON APIs, model calls, webhooks, MCP transports — first sketched by Tim Berners-Lee in 1991 as a one-page, GET-only protocol, its request/response grammar stabilized by mid-decade into the shape it still has: method, URL, headers, body over; status, headers, body back. JSON, which Douglas Crockford specified in the early 2000s from a subset of JavaScript, became the lingua franca of the payloads. Students need the working set — GET versus POST, status codes, content types, auth headers, idempotent reads versus consequential writes, timeouts and retries — because most "integrations" are just structured agreements about these. AI adds the pattern that changes interface design: streaming. A model generates over seconds, and the WHATWG Streams API lets both server and browser process data incrementally, so partial results become visible as they arrive. Once HTTP and streams are understood as primitives, every SDK reveals itself as a convenience over a protocol you can inspect with developer tools.

**Builder question:** What exactly crosses the network in this interaction, and what should happen if the connection ends halfway through?