Dev Handbook

The developer's field guide

Understand the system.
Build with confidence.

Practical explanations of the software you build.
Follow the mechanics, connect the ideas, and find your next question.

Start with a single request Explore the handbook

Where do you want to go?

136 guides. Pick a topic and follow your curiosity.

01

Backend engineering

Follow requests. Shape APIs. Make the right trade-offs.

Explore this topic
02

System design

Understand how systems scale, and where they break.

Explore this topic
03

Agentic AI

Build a clear model of agents, retrieval, and tools.

Explore this topic
04

Java & Spring

Connect the framework to what happens in production.

Explore this topic
A good place to begin

One request.
The whole picture.

Trace a request from the browser to the database and back. Meet the parts of a backend in the order they actually do their work.

Follow the request
  1. 1
    BrowserSend the request
  2. 2
    Edge & routingFind the destination
  3. 3
    ApplicationMake the decision
  4. 4
    DatabaseRead and write the data
Put the ideas to work

Design walkthroughs

Feeds, crawlers, caches, and the decisions behind them.

Keep the details close

The reference shelf

Terms, status codes, database indexes, and useful resources.