An API (application programming interface) is a defined way for one piece of software to request data or actions from another. Your app sends a request to an endpoint, often with an API key for permission, and receives a response, usually in JSON format. APIs let apps, automations and AI tools work together.
The restaurant analogy
Imagine a restaurant. You do not walk into the kitchen and cook. You read the menu, tell the waiter what you want, and the waiter brings your food. An API is the waiter: it takes your request to another system (the kitchen) in an agreed format (the menu) and brings back the result.
How an API request works
- Endpoint: the address you send the request to, such as
https://api.example.com/weather. - Method: what you want to do. Common methods are
GET(read data),POST(create something),PUTorPATCH(update) andDELETE. - Parameters or body: the details, such as
city=Lahore. - Authentication: usually an API key or token that proves you are allowed to use it.
- Response: the data you get back, plus a status code such as
200(success),401(not authorised) or404(not found).
JSON: the language of APIs
Most modern APIs send data as JSON, a simple text format of keys and values:
{ "city": "Lahore", "temperature_c": 31, "condition": "Sunny" }Learning to read JSON is one of the most useful skills for anyone working with automation or code.
Everyday examples
| You do this | An API does this behind the scenes |
|---|---|
| Pay online | The shop's site calls a payment provider's API |
| See a map on a website | The site calls a maps API |
| Log in with Google | The site uses Google's sign-in API |
| Ask an AI chatbot in an app | The app sends your message to an AI model's API |
| A form updates a spreadsheet | An automation tool calls the spreadsheet API |
API keys and safety
API keys are like passwords. Never share them publicly, paste them into public code repositories or put them in front-end code that anyone can view. Store them in environment variables or the credential manager of your automation tool. Many API services charge per use, so a leaked key can cost money.
REST, and other styles
Most web APIs follow REST conventions: resources at clear URLs and standard methods. You may also meet GraphQL (where you request exactly the fields you want) and webhooks, which work in reverse; see webhooks explained.
Why APIs matter for your skills
- Automation: connecting apps that have no ready-made integration requires calling APIs directly.
- AI apps: every AI application calls a model's API.
- Web development: front ends fetch data from back-end APIs.
Our AI automation and web development courses both teach working with APIs hands-on.
Frequently asked questions
Do I need to code to use APIs?
Not necessarily. Automation tools like n8n and Make have HTTP request modules that call APIs without full programming.
Are APIs free?
Some are free, many have free tiers, and others charge per request.
What is API documentation?
The instructions that explain an API's endpoints, parameters and responses. Learning to read docs is an essential skill; see how to read documentation.
