NETWORKING FUNDAMENTALS: WHAT ACTUALLY HAPPENS WHEN YOU VISIT A WEBSITE
NetworkingJan 8, 2026
Understanding networks is essential for every developer. Follow the journey of a single HTTP request from browser to server and back.
Every time you visit a website, an intricate chain of events unfolds in milliseconds. Understanding this chain makes you a fundamentally better developer.
The journey of an HTTP request:
1. DNS Resolution: Your browser asks a DNS server to translate a domain name to an IP address. This involves recursive queries through a hierarchy of DNS servers.
2. TCP Handshake: A three-step process (SYN, SYN-ACK, ACK) establishes a reliable connection between your browser and the server.
3. TLS Handshake: For HTTPS, an additional negotiation encrypts the connection. The server presents its certificate, and both parties agree on encryption methods.
4. HTTP Request: Your browser sends headers (including cookies, accepted formats, and caching information) and optionally a request body.
5. Server Processing: The server receives the request, routes it, executes application logic, queries databases, and constructs a response.
6. HTTP Response: The server sends back status codes, response headers, and the response body (HTML, JSON, etc.).
7. Rendering: Your browser parses HTML, constructs the DOM, applies CSS, downloads additional resources, and executes JavaScript.
Key protocols to understand:
- TCP: Reliable, ordered delivery. Used for web browsing, email, file transfers.
- UDP: Fast, connectionless. Used for gaming, video streaming, DNS queries.
- HTTP/2 and HTTP/3: Modern protocols that multiplex requests and reduce latency.