How DNS works
How the Domain Name System turns names like www.example.com into IP addresses, from the tree of domain names and the servers that hold them to caching, record types, message formats and security.
Topic
The web
The protocols and building blocks behind every website, from how a browser finds a server to how pages are requested, delivered and cached.
Articles
How HTTP works
How the Hypertext Transfer Protocol carries the web, from URLs, requests, methods and status codes to caching, cookies and the three versions in use today, HTTP/1.1, HTTP/2 and HTTP/3.How OAuth and OpenID Connect work
How OAuth 2.0 lets an app act on your behalf without your password, from the four roles and the authorization code flow to PKCE, access and refresh tokens, JSON Web Tokens, sign-in with OpenID Connect, and today's security best practices.How QUIC works
How QUIC, the transport protocol under HTTP/3, combines the jobs of TCP and TLS on top of UDP, from its packets, connection IDs and streams to its one-round-trip handshake, loss recovery and connection migration.How Unicode and UTF-8 work
How computers turn text into numbers and bytes, from ASCII to Unicode's code points and planes, how UTF-8 and UTF-16 encode them, why one visible character can be several code points, and why the web settled on UTF-8.How WebSockets work
How WebSockets give a web page a lasting two-way connection to a server, from the HTTP upgrade that opens it to frames, masking, pings and the closing handshake, and how they run over HTTP/2 and HTTP/3.