API libraries
An API (Application Programming Interface) is a set of rules that lets two software systems talk to each other. It defines how one program requests data or actions from another.
- Purpose: APIs allow apps, websites, or devices to share data and functions without knowing how the other system works inside.
- Example: When your app shows weather info, it gets that data from a weather API instead of collecting it itself.
- Common Types:Web APIs (REST or GraphQL): Used over the internet to send and receive data (usually in JSON format).Library APIs: Built into software libraries so developers can use certain features.Operating System APIs: Allow apps to use system resources like files or hardware.
- Benefits:Saves development time.Promotes integration between systems.Improves scalability and automation.
Here are practical examples of how APIs are used in real life:
- Weather apps
- Use APIs like OpenWeatherMap to get live temperature, humidity, and forecast data.
- Example: Your app shows “28°C and cloudy” by fetching data from the weather API.
- Login with Google or Facebook
- Apps use OAuth APIs from Google or Meta to let users sign in without creating a new account.
- The API returns user profile info securely.
- Online payments
- Websites use Stripe or PayPal APIs to handle credit card transactions.
- The API processes the payment and returns confirmation or error messages.
- Maps and location
- Apps use Google Maps API to display maps, routes, and nearby places.
- Example: A delivery app uses it to calculate driving distance and time.
- Messaging and chatbots
- Businesses use WhatsApp or Telegram APIs to send automated messages or alerts.
- Example: A clinic sends appointment reminders through a chatbot.
- E-commerce
- Product catalogs, shipping rates, and stock updates come from APIs.
- Example: Shopify or Amazon APIs help sync inventory with a seller’s app.
- AI and image generation
- Tools like OpenAI or Stability AI provide APIs to generate text or images from prompts.
- Example: Your web app calls an API to create a new image based on user input.
- Finance and crypto
- APIs like CoinGecko or Yahoo Finance supply market prices and stock data.
- Example: A dashboard shows live cryptocurrency prices updated every few seconds.
Where to find some free and public API libraries
exifly
public-apis
Tools for test, debug and work with API
1. Postman
Postman is a complete API development and testing tool. You can send API requests, inspect responses, test endpoints, and document APIs. It supports REST, GraphQL, and WebSocket APIs. Great for developers testing integrations or debugging backend services.
2. Swagger (OpenAPI)
A framework for designing, documenting, and testing APIs. Swagger UI lets you interact with API endpoints through a visual interface, often used in API documentation.
3. Insomnia
Similar to Postman but simpler. It focuses on fast, clean API testing with support for REST and GraphQL. It’s open source and often preferred for its lighter interface and plugin system.
Adam JirounSenior Product Marketing Manager, Kong
4. Hoppscotch
A free, open-source, web-based alternative to Postman. It runs in your browser and supports REST, GraphQL, and WebSocket requests. Good for quick tests without installing software.
