What is an API in Simple Terms – APIs for Dummies
In this article, I will answer the question “What is an API?” in simple terms, no technical jargon, and no confusion.
Introduction
Unless you’ve been living under a rock, you likely heard about APIs. Either in the context of the ChatGPT API, payment APIs, or even weather APIs. But you are wondering, what in the world is an API? What are its use cases? And how does it work?
Despair no more! I will answer all your questions in easy-to-understand layman’s terms.
What is an API? In Simple Terms
An API, or Application Programming Interface, is a set of rules that allows one software application to access the services and data of another.
It’s a way for programs to communicate with each other. Technically, it consists of a set of operations, inputs, outputs, and underlying types.
For example, when you use a weather app on your phone, it sends a request to a remote server via an API to get the latest weather information.
How Does an API Work? In Simple Terms
An API, or Application Programming Interface, is like a waiter in a restaurant. Just as a waiter takes your order and brings you food from the kitchen, an API takes requests and delivers responses between different software programs.
For example, when you book a flight online, an API communicates between the airline’s database and the website to show you available flights and process your booking.
In other words, the API is the go-between that allows the two systems to ‘talk’ to each other, making sure your request is understood and the correct information is delivered back to you.
What is an API Key?
An API Key is like a special passcode that identifies and allows access to an API. It’s a string of letters and numbers that acts like a key to open the door to a software application’s data and functionalities.
An API key generally looks something similar to the following:
abc123xyz456abc123xyz456abc123xyz456abc123xyz456Think of this key like this: You have a treasure chest (the API) filled with gold coins (data and functions). To open the chest, you need a key (the API Key). This key ensures that only those with permission can access the treasure.
For instance, imagine you have an online shopping app. When a customer selects items and proceeds to checkout, the app uses an API Key to request payment processing from a payment service’s API. The service verifies the key, and if it’s valid, it responds, “Alright, the payment has been processed,” and confirms the transaction back to your app.
This interaction ensures secure and efficient transactions.
Note: It’s important to keep API Keys safe because if they fall into the wrong hands, someone could access all the treasures without permission. That’s why they’re often kept secret and used carefully, much like how you wouldn’t share the key to your house with just anyone.
What is an API Used for?
So, to summarize, APIs are used to let different software applications talk to each other. Think of them as the middlemen that allow your phone apps to grab information from the internet, like fetching your social media updates or bank balance.
Here are a few more examples to better understand what an API is used for:
- Login with Social Media: Websites allow you to log in using social media accounts thanks to APIs that authenticate your identity without sharing your login details.
- Payment Processing: Online stores use payment APIs to handle transactions, so you don’t have to enter your card details every time.
- Travel Booking: Travel websites aggregate flights, hotels, and car rentals from various providers using APIs to give you a one-stop-shop for planning your trip.
What is an API Call?
An API call is like making a phone call to a friend to ask for some information. In the tech world, it’s when one software program asks another for some data or to do a task.
Here’s a simple example with a breakdown:
- The Request: Your app wants to know today’s weather.
- The Call: It sends an API call to a weather service’s API, asking for the info.
- The Response: The weather service’s API checks the request, finds the weather data, and sends it back.
So, an API call is essentially a conversation between two software programs, where one asks for something and the other responds with the requested information.
What is an API Server?
An API server is like a busy restaurant kitchen that prepares various dishes (services and data) upon request. It’s the part of a software system that receives API calls, processes them, and then sends back the requested information or performs the desired action.
Again, let’s use a payment API as an example. Imagine you’re at a cafe, and after enjoying your coffee, you decide to pay with your phone. You tap the payment app, which sends an API call to the API server of your bank.
The server is like the cafe’s cashier—it checks your account, processes the payment, and sends back a confirmation that the transaction is complete.
In technical terms, the API server is the software component that hosts the payment API, handling requests like “charge this amount” or “refund this transaction” and interfacing with the payment processing system to execute these commands.
It ensures that the right amount is charged to the right account and that all the details are in order for a smooth transaction.
So, every time you make an online payment without entering your card details, it’s the API server working in the background, making sure your payment is processed quickly and securely.
What is an API Client?
An API client is like a customer in a store, using a shopping basket to gather items. In technical terms, it’s a tool that helps you make requests to an API server and handle the responses.
For example, when you’re using an online payment service to buy a new book, the website’s API client sends a request to the payment API server with your transaction details. The server processes the payment and sends back a confirmation to the API client (website), which then tells you that your purchase was successful.
When you go to the checkout counter; the cashier (API server) processes your payment and hands you a receipt (confirmation), while your shopping basket (API client) is what you use to carry your chosen book to the counter.
What is an API Payload?
An API payload is the part of the sent data that carries the actual information you want the API to process. It’s like the contents of a letter, while the envelope and address are the rest of the API request.
Imagine you’re buying a concert ticket online. When you enter your payment details and hit ‘pay’, the website’s API client packages up your payment info (like card number, expiration date, and security code) into a payload. This payload is then sent off to the payment API server, which looks inside, confirms everything is in order, and processes your payment. It’s the crucial part of your API ‘letter’ that tells the server what you want to do.
What is an API Endpoint?
An API (Application Programming Interface) endpoint is a specific URL where an API service can be accessed by a client application. It serves as a gateway for interaction with the API, allowing the client to send requests and receive responses.
For example, suppose we have an API for weather data. An endpoint for retrieving the current weather in a specific city might look like this:
https://api.weather.com/current?city=NewYorkIn this example, https://api.weather.com/current is the base URL of the API, and city=NewYork is a parameter indicating that the client wants the weather data for New York City. When a client application sends a request to this endpoint, it will receive a response containing the current weather information for New York.
What is an API Limit?
An API limit refers to the maximum number of requests that a user or application can make to an API within a specified time period, such as per hour, per day, or per month.
API providers impose limits to ensure fair usage, maintain system stability, and prevent abuse or overloading of their servers.
Conclusion
That’s it! You’ve learned what is an API in simple terms, how APIs work, and how API servers and clients communicate.
FAQ
What is an API Specification?
An API specification is a formal document or description that outlines the functionality, endpoints, parameters, data formats, and behavior of an API. It serves as a blueprint for developers to understand how to interact with the API effectively.
What is an API Gateway Used for?
An API gateway is a centralized service that acts as an intermediary between clients and backend services, routing requests, enforcing security policies, managing traffic, and providing features like rate limiting, authentication, logging, and monitoring. It simplifies the client-server interaction and enhances the scalability and security of an API ecosystem.
What are RESTful APIs?
RESTful APIs (Representational State Transfer) are a type of API architecture that follows a set of principles and constraints, such as statelessness, uniform interface, and resource-based interactions. They use HTTP methods (GET, POST, PUT, DELETE) to perform CRUD (Create, Read, Update, Delete) operations.
