APIs & Integration
REST, GraphQL, gRPC, webhooks, and message queues - how systems actually talk to each other.
Watch it animated → Interactive, click-through walkthroughs for APIs & Integration concepts.Basic
What an API Actually Is An API is a defined way for one program to ask another for something - a contract that says what you can ask and what you'll get back - and this guide builds that mental model from the ground up before you touch any code.
HTTP & JSON: the API Building Blocks Every web API is made of two things: HTTP carries the message, JSON carries the data. Learn both well enough to read any API call with confidence.
Reading API Docs & Using Postman How to go from an unfamiliar API docs page to a working request: read the reference, fire the call in Postman or curl, and read the response - without guessing.
Intermediate
REST APIs, Explained The mental model behind the web's dominant API style - things live at URLs, HTTP methods are the verbs you apply to them, and every request stands on its own.
GraphQL, Explained What GraphQL actually is, the REST pain it was built to fix, how its typed schema and single endpoint work, and the real trade-offs that tell you when to reach for it and when not to.
gRPC, Explained What gRPC actually is - a contract-first way for internal services to call each other fast - how the .proto file, code generation, and HTTP/2 streaming fit together, and the real trade-offs versus REST and GraphQL.
Webhooks & Message Queues - Events and Async Integration Beyond Request/Response How services talk to each other when one of them isn't waiting for an answer: webhooks let another system call your URL when something happens, and message queues let your own services hand off work to be done later.
Rate Limits and Retries Calling a flaky or throttled API without melting it or yourself: 429s, exponential backoff with jitter, idempotency, and circuit breakers.
Realtime APIs: WebSockets vs SSE vs Polling How to push live updates: the real tradeoffs between polling, Server-Sent Events, and WebSockets, and which to reach for when.
Advanced
Versioning & Designing APIs That Last An API is a promise to everyone who built on it: what counts as a breaking change, how to evolve without breaking clients (additive-first, then versioning + deprecation), and the durable-API checklist - consistent shapes, pagination, idempotency, rate limits, and great docs.