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Web and API basics

Module 2 of the System Design Masterclass. Every lesson here is free to read, with no account.

  • 7 lessons
  • 1 h 36 min of reading
  1. 7What happens in one web requestThe steps from typing a web address to seeing the page: DNS, a TCP connection, an HTTP request and response, plus UDP, redirects and cookies.12 minCore
  2. 8DNS: how a request finds your serverHow DNS records turn a name into an address, how the TTL decides how fast a change reaches users, and how geo routing sends each user to a nearby server.12 minDepth
  3. 9REST and CRUD: resources, methods, status codesHow a REST API names things with URLs, what GET, POST, PUT, PATCH and DELETE mean, which are idempotent, and which status code to return.12 minCore
  4. 10API errors and paging through resultsHow to shape an error so a program can read it, why a long list is returned in pages, offset against cursor paging, and how an OpenAPI file documents the API.12 minCore
  5. 11Changing an API without breaking callersWhich API changes are safe, which break callers, and how versions, deprecation dates and a slow move from the old field to the new one keep old apps working.12 minCore
  6. 12REST, gRPC or GraphQLThree ways for one program to call another, what each is good at and what it costs, how JSON and Protobuf differ, and how to pick by who calls whom.24 minCore
  7. 13Cloud basicsWhat the cloud is in plain words: rented compute, storage and network, paid for by use, and the same three blocks at AWS, Azure and Google Cloud.12 minCore

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