APIs & JSON Explained — How Systems Talk to Each Other

APIs & JSON

1 min readPublished 22 Jul 2026

Track your progress. Sign in to mark this guide complete and build your Job Readiness Score.

An API (Application Programming Interface) lets systems talk to each other — the backbone of cloud automation and integrations. Most modern APIs are REST and speak JSON.

Interactive explainer

REST APIs & JSON

How systems talk to each other.

Tap or hover a part to learn more.

1. Endpoint & method

URL + verb.

You call an endpoint (a URL) with an HTTP method: GET (read), POST (create), PUT (update), DELETE (remove) — mapping to CRUD over the web.

Check your understanding

1. Which HTTP method creates a resource?

2. What does a 401 status code mean?

Keep learning

APIs & JSON Python AWS Developer Associate

Practise this in AI Interview™

The essentials

REST API — you call an endpoint (URL) with an HTTP method (GET read, POST create, PUT update, DELETE remove).
Status codes — 200 OK, 401 Unauthorised, 404 Not Found, 500 Server Error tell you what happened.
JSON — the lightweight text format ({"name": "Ada"}) APIs use to send structured data.
Authentication — API keys or tokens (e.g. OAuth) prove who's calling.

APIs are how you automate the cloud and integrate tools — call them from Python or PowerShell and parse the JSON response.

Interview Intelligence

How this topic actually shows up in interviews — and how to demonstrate you understand it.

Why employers ask about this

APIs connect everything in the cloud; automating them is a core modern engineering skill.

Technical questions

What do the HTTP methods GET, POST, PUT and DELETE do?+

GET reads, POST creates, PUT updates and DELETE removes — mapping to CRUD over a REST API.

Behavioural questions

Tell me about integrating two systems.+

Show calling one system's API and passing data (JSON) to another, handling errors.

Real-world scenarios

“You need one tool to notify another automatically.”+

Expected answer: Call the target's REST API (POST with a JSON body and a token) when the event occurs — event-driven integration.

Practise in AI Interview™Rehearse these questions, scored.Plan with Career Coach™A personalised path to your goal.Evidence it in Career Passport™Prove this skill to employers.

Employability Intelligence

Where this knowledge takes you — the jobs, skills and certifications it feeds into.

Relevant roles

Automation EngineerCloud EngineerIntegration Developer

Skills you're proving

REST APIsJSONIntegration

Recommended certifications

Microsoft PL-900 / AZ-204AWS Developer Associate

Career progression

Programming Fundamentals → cloud/automation roles.

What employers expect

That you can read, write and debug code/scripts and automate repetitive work.

Frequently asked questions

What is a REST API?

A web API that uses HTTP methods (GET/POST/PUT/DELETE) against endpoints, typically exchanging JSON data.

What is JSON?

JavaScript Object Notation — a lightweight, human-readable text format for structured data used by most APIs.

What does a 401 status code mean?

Unauthorised — the request lacked valid authentication credentials.

Practise what you've learned

Turn this guide into real, evidenced progress

Missiora helps you measure, improve and evidence the capabilities employers actually value — start with the tools best suited to this topic.

Published by

Missiora

Missiora is an AI Employability Intelligence platform. Our resources are researched and reviewed by the Missiora team to help you measure, improve and prove your career readiness.