Common core

Data & Applications

How software actually stores and moves information — files, databases, APIs, JSON.

What you'll actually learn

Every application, underneath its UI, is really just moving information between three places: a file, a database, and a network request — usually shaped as JSON along the way. This track covers how those three actually connect: what a database genuinely buys you over a file, what an API is doing when your app "talks" to another service, and why JSON became the shape almost everything settles into in between.

What you'll be able to do

You'll be able to look at a real application and trace exactly where a piece of data lives at any given moment — sitting in a database table, in flight as a JSON payload, or written to disk — instead of treating "the backend" as an opaque black box. That mental model is the foundation everything else in software development actually builds on.

Syllabus

1Files vs. Databasescore~8 min

2What Is an API?core~10 min

3JSON: Data Computers Can Agree Oncore~10 min

4API Keys and Tokens: Proving Who You Are Without a Login Formcore~11 min

5Environment Variables: Configuration Without Editing Codeadvanced~18 min

6Command-Line Arguments: Making One Script Do Many Thingsadvanced~18 min

7Webhooks: When the API Calls You Insteadcore~10 min

8Rate Limiting: Protecting an API From Being Loved to Deathcore~10 min

9Caching Basics: Not Doing the Same Work Twicecore~10 min

10Logging: Why print() Stops Being Enoughadvanced~20 min

11Synthesis Mission: From Transistor to APIexpert~35 min

Leads to

Go Automation & Scripting Databases: The Foundations How the Web Works C AI: How It Actually Works Web Security Docker Python

Frequently asked

How long does Data & Applications take to complete?

Roughly 3 hours across 11 hands-on quests — you can go at your own pace and pick up exactly where you left off.

What do I need to know before starting Data & Applications?

You should be comfortable with Shell, Networking first — the skill tree unlocks Data & Applications once you've cleared those.

Is Data & Applications free to learn?

Yes — Data & Applications is fully available on the free tier, starting with a free first quest and no payment method required to sign up. Plus and Elite remove pacing limits but don't gate any of the Data & Applications curriculum behind a paywall.

Start this skill for free

Create a free account and begin your first quest — no card required.

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