From the comfort of my couch, I can easily accomplish a variety of tasks – ordering groceries, having food delivered, mapping the drive to Barnes & Noble, and checking the weather to determine if staying indoors is the best option. While some may view this as lazy, I consider it highly convenient. And I owe these conveniences to the power of APIs.

APIs, the crucial enablers of modern conveniences, are the glue that binds diverse applications together. These programming interfaces allow seamless communication and information sharing across different platforms, facilitating the integration that powers our daily lives. Moreover, APIs shoulder much of the complex backend work required for developing new applications, streamlining the creation of innovative digital tools and services.
I have compiled a detailed beginner’s guide and tutorial on how to use APIs.
Table of contents:
- [What is an API?]
- [Why use an API?]
- [Getting started with APIs]
- [How to use an API]
- [REST vs. GraphQL vs. SOAP APIs]
- [Types of APIs]
- [API FAQ]
What is an API?
An API acts as a digital intermediary, allowing different software applications to communicate and share information with one another. It outlines the specific methods, parameters, and data formats that developers can use to access features or retrieve data from an application or online service.

Consider your go-to weather app – it taps into APIs to fetch real-time data from meteorological services and deliver that information straight to your device. Or think about using a social media login (like Facebook) to access another app – there are APIs working behind the scenes to securely authenticate your identity.
Why use an API?
Without APIs, we’d be stuck relying on old-fashioned paper maps to find our way around – and I’d probably get lost all the time. But APIs allow us to tap into existing data sources, rather than having to build everything from the ground up. For example, when you use a navigation app, it’s sending requests through APIs to access real-time location data from cell towers and GPS satellites.
From a developer’s perspective, APIs provide a valuable shortcut – they can leverage pre-built functionalities, allowing them to focus their efforts on creating new and innovative features. Take Planefinder, an app that tracks planes in real-time – rather than having to build their own mapping system from scratch, they used the Google Maps API. This freed them up to devote their time and resources to developing Planefinder’s unique features and capabilities.
Using apidog, you can easily facilitate seamless integration between different systems, enabling smooth data exchange across applications. This integration capability proves invaluable when your business needs to share information across software platforms – like connecting your customer relationship management (CRM) system with your email platform. apidog is built on API technology to provide users with these convenient cross-system collaboration and data sharing capabilities.
Apidog is an API management platform that empowers seamless integration and smooth data sharing across your business systems. Through apidog’s robust API capabilities, you can easily connect applications like your CRM and email platform, simplifying complex workflows and enabling valuable cross-system collaboration.
Getting started with APIs
I’ll be throwing a lot of jargon your way, so before you get started, here are a few API terms you should get to know.
Term | Definition |
---|---|
API key | A unique passcode of letters and numbers that grants access to an API |
Endpoint | The digital location where an API receives requests about its resources |
Request method | Uses HTTP methods (GET, POST, PUT, DELETE) to tell the API what you want it to do |
API call | Process of a client (your computer) making an API request to a server |
Status code | A number code that appears in the body of an API response that tells you if your request was successful or not |
API server | Authenticates and processes API requests before delivering an appropriate response |
API response | A response generated by the API server and returned to the client (your computer) |
API keys
Much like a password, an API key is a unique string of letters and numbers that serves as an access code or authentication token. This key is required to access most APIs, as it is a critical security measure to track and control API usage. Just as you need a password to access your apps, you need a valid API key to access and utilize an API’s data and functionality – ensuring only authorized users or applications can do so.

We’ll cover how to obtain and use these keys in the next section.
API Endpoints
An API endpoint refers to a specific URL or web address that serves as the access point for an API, allowing it to communicate with another application. These endpoints act as standardized locations where requests are received and responses are sent back. They provide a clear and structured way for users to interact with an API’s capabilities, much like the buttons on a vending machine.

Just as you select a particular snack by pressing a button on a vending machine, you can “press” an API endpoint by making a request to that specific URL. The API then knows exactly what information or action you’re looking for and provides you with the corresponding response, delivering the digital “Snickers bar” you need.
Request methods

To communicate what you want to accomplish through an API endpoint, you’ll need to make a request using one of four specific HTTP methods:
- GET: This method is used to retrieve particular data from the API.
- POST: This tells the API you want to add or post new data to the server.
- PUT: This method is for updating existing resources on the API.
- DELETE: As the name implies, this is used to remove existing data from the server.
These request types are also commonly referred to as CRUD – Create, Read, Update, and Delete. Many public-facing APIs will typically only allow GET (Read) requests, to prevent unauthorized parties from modifying their data. After all, you wouldn’t want just anyone accessing a meteorology API and altering weather information.
API calls
An API call is the end-to-end process of making a request, having the API retrieve the data you need, and then receiving the corresponding response. All you have to do is make the request using one of the HTTP methods we covered earlier.

Think of it like ordering a drink at a coffee shop – you tell the barista what you want, they input your order into their system, and then hand you the finished beverage. An API call works in a very similar way, just without the caffeinated result.
Status codes
When you make an API request, you’ll receive a status code – a 3-digit number that tells you if your request was successful or not. Codes starting with 2 mean your request worked. Codes starting with 4 mean there was a problem. These status codes let you know the outcome of your request.
How to use an API
I’ll be using Apidog to show you an example of using an API. Apidog is a pretty accessible way to use APIs, that offer user-friendly interfaces for APIs.
1. Pick an API
There are thousands of public APIs available for use. You can search directories like GitHub or Google’s API Explorer to find ones that interest you. Most sites will list their available APIs under an Advanced settings or Developers section, often at the bottom of the website.

I’ll be using OpenAI API platform.

2. Consult the API documentation
Every API should provide you with documentation to get started. This will typically include a reference section detailing the available objects, parameters, and endpoints you can access. There are also often examples or “quickstart” guides expressed in popular programming languages, which explain:
- What functionalities the API offers
- Any dependencies or requirements for using the API
- How to actually utilize the API
And if the API requires an API key, you’ll find that information in the documentation as well.
3. Write a request
Step 1: Create an OpenAI account
If you haven’t already, go to the OpenAI platform, and create an account.
Step 2: Create a project (optional)
You’re logged in. Before we move to grabbing our API keys, you can organize them by project if you’d like. This lets you collaborate with your team, set custom billing limits, and have better visibility over usage.
If you want to use this feature, on the top left of the screen, click Default project and then Create project. (You can also access the Organization overview page from here.)

Step 3: Create an OpenAI API key
Since the OpenAI API isn’t free, you need to create an API key so the platform knows who you are and who to bill the work to. To generate an OpenAI API key, look to top-right side of the screen, and click Dashboard.

This is the OpenAI Playground that I mentioned before. It has all the tools for testing and developing with the OpenAI API. After you read the welcome message pop-up, you can click Get Started to continue.