What is an API? A beginner's guide to programming

Ever wondered how your bank keeps track of every time you swipe your credit card, or how weather apps can give you an accurate forecast minute-by-minute?

The answer is with APIs or Application Programming Interfaces. An API acts as a digital messenger, carrying requests between different software applications to share data and trigger actions.

Think of an API call as a waiter in a restaurant. You (the client) place an order (make a request), and the waiter (API) delivers your request to the kitchen (server). The kitchen prepares your meal (processes the request) and sends it back through the waiter to your table (response).

Having a solid understanding of how APIs work is essential for almost anyone interested in technology and how our digital world operates. It's often the first step in learning how to program, but we want to provide an overview of APIs for a non-technical audience, so you can get a simple explanation without all the jargon.

For people looking to work with APIs without all the coding involved, we recommend checking out IFTTT. At IFTTT we connect over 1000 APIs together in our easy-to-use Applet builder. We make it simple to connect and automate your favorite apps and services. Get started for free today!

Understanding APIs for beginners

An API (Application Programming Interface) acts as a digital messenger between different software applications.

Physically, they appear as chunks of code within a program, and don't necessarily stand out to undertrained eye. All APIs have the following (which we will cover in detail later): an endpoint, a method, headers, and a request body.

APIs lay out specific rules (protocols) that applications must follow to communicate and share information. These rules create a standardized way for software to request data or actions and to give results as expected.

This to-and-from of data is known as the client server architecture, which is an important concept that defines who receives API calls.

What is client-server architecture

The client-server architecture forms the backbone of API communication. Here's how it works:

The client side: The client is the one that makes requests for specific resources or actions. The client does this by sending data in a format the server understands and waits for the server's response.

This request is known as an API call.

The server side: The server "listens" for incoming requests, processes requests based on defined rules, then returns appropriate responses or error messages.

What is an API call: A real life example

A great example of an API call is the weather app on your smartphone. Because it would be impossible to store millions of gigabytes of weather data on your phone, these apps send out API calls to weather servers every time you access the forecast

Pretend you check the forecast in Cupertino. The weather app will send an API call to a local database. The server processes this request, retrieves the relevant weather data, and sends it back to your app in a format it can understand and display. And the craziest part: it all happens in a fraction of a second.

This client-server relationship enables powerful integrations between different systems. A single application can interact with multiple APIs simultaneously, pulling data from various sources and combining them into the overall user experience. Below are two examples of API calls in the form of our Applets.

Components of an API call

Remember we mentioned the four essential components that work together to create a successful API? Let's break down each component:

1. Endpoint/URI (Uniform Resource Identifier): This acts as the specific address for your API endpoint.

Example: https://api.example.com/users/123

The URI contains the base URL and path. This identifies the exact resource you want to interact with.

2. Method: This defines the action you want to perform.

Common methods include:

• GET: Retrieve data
• POST: Create new data
• PUT: Update existing data
• DELETE: Remove data

Example: GET https://api.example.com/users retrieves a list of users

3. Headers: These contain additional data about your request.

Common header fields include:

• Authorization: Authentication tokens (to make sure data gets transferred securely)
• Content-type: Specifies data format (e.g., application/JSON)
• Accept: Defines expected response format

4. Request: The request carries the data in your request.

The Request body is used primarily with POST and PUT requests and is typically formatted in JSON.

Example: json { "username": "john_doe", "email": "john@example.com", "age": 30 }

How do you start building APIs?

The good news is that you don’t need to be a software engineer with years of experience to understand the basics of setting up an API. At its core, building an API is about clearly defining what information can be requested, how it should be requested, and what gets sent back.

The first step is finding a tool where you can code your API. There are tons of options for absolute newbies all the way to seasoned programmers. Technically, you could even build out your first API with pen and paper!

Then, you're left with deciding what problem your API will solve. Maybe you want to share product data with a website, collect form submissions, or let another app trigger an action. A good API focuses on a small, clear purpose. This keeps it easier to maintain and understand.

Next, you define your endpoints and methods. Choosing the correct HTTP method (GET, POST, PUT, DELETE) ensures that anyone using your API understands exactly what action is happening.

After that comes data structure. Most modern APIs use JSON because it’s lightweight and human-readable. Consistent formatting makes your API easier for other developers to work with. Consider learning more about authentication tokens and using those for added security.

Finally, testing and documentation are what transform a working API into a usable one. You'll probably have to trial a couple sets of code before you find something you're fully happy with.

If all of this sounds technical, don’t worry, you don’t always have to build APIs from scratch to benefit from them. Platforms like IFTTT let you connect services through pre-built APIs using a visual interface. Instead of writing code, you define triggers and actions, and IFTTT handles the communication behind the scenes.

What are REST API calls

Once you've started researching more about APIs, you'll likely run into the term "REST API" soon enough.

The REST (Representational State Transfer) style has transformed web services design since its introduction in 2000. This architecture creates scalable, maintainable web services that follow specific principles and constraints.

Core principles of RESTful APIs

RESTful APIs are built on several principles that guide their design and implementation. By following these rules, you can make a more standardized API that is readily adopted in many different applications. Here are some key fundamentals:

Resource-based: Every resource gets a unique URL.

State management: No client context stored between requests.

Standard HTTP methods: Uses GET, POST, PUT, DELETE.

Multiple data formats: Supports JSON, XML, YAML.

Self-descriptive messages: Each request contains all needed information.

Standard HTTP status codes in REST APIs

REST APIs use standard HTTP status codes to indicate common request outcomes. They are broken up into five categories:

• 1xx - Informational
• 2xx - Success
• 3xx - Redirection
• 4xx - Client Errors
• 5xx - Server Errors

These status codes provide standardized ways to communicate the results of an API request. This makes RESTful APIs more predictable and easier to work with across different services.

Practical uses of API calls

In essence, API calls are how the internet works. They enable apps to provide users with interactive and personalized experiences by connecting various digital services. This allows apps to utilize new features without having to build everything from scratch. Here are some real-world examples of how API calls are used on IFTTT:

Demystifying APIs with IFTTT

Giving IFTTT a try is the best way to use APIs without having to worry about coding them from scratch. With a simple logic-based interface, IFTTT feels intuitive, and allows millions of people across the world to automate their small businesses, smart homes, personal schedules, and more.

Here’s how to get started with IFTTT:

1. Create an IFTTT account: If you don’t have an account, sign up on the https://ifttt.com.

2. Connect services: Use the search bar to find whatever services you are interested in. Click the “Connect” button and link your account by signing in. You can connect unlimited services for free.

3. Browse Applets: Head to the Applets tab in IFTTT and search through our library for an Applet that works for you. Don’t worry, we have over a million (and counting) Applets for you to choose from.

You can also create your own with our easy-to-use Applet builder. Here’s a simple list to guide your Applet creation:

1. Sign in to IFTTT.
2. Connect services.
3. Click “Create” to start a new Applet.
4. Select “If This” trigger.
5. Choose “Then That” action.

For more guidance, check out our full guide to learn how to start building Applets in just a few minutes.

If you find yourself inspired to take the next step in automating your life, trying IFTTT only takes a few minutes and is free. Join millions of others and see why IFTTT is the most trusted platform for automation.

FAQs

What is an API call and why is it significant in software development?

An API call, or API request, is a communication method used by software applications to interact with each other through an Application Programming Interface (API). It plays a huge role in software development by enabling different applications to share data and functionality seamlessly.

What are the main components of an API call?

The main components of an API call include the endpoint, HTTP method (such as GET or POST), headers, and request. Each component serves a specific purpose, such as identifying the resource being accessed, specifying the action to be taken, and providing additional data.

How does the process of making an API call work?

When an API call is made from a client to a server, the server processes the request. It then returns a response that includes status codes indicating success or failure and any requested data. This process allows for effective communication between different software systems.

What distinguishes RESTful API calls from other types of APIs?

RESTful APIs adhere to REST architecture principles, which emphasize stateless communication and resource manipulation using standard HTTP methods. Key characteristics include using URIs for resource identification and supporting formats such as JSON or XML.

What are some common HTTP methods used in REST API calls?

Common HTTP methods used in REST API calls include GET (to retrieve data), POST (to create new resources), PUT (to update existing resources), and DELETE (to remove resources). These methods define the actions that can be performed on the specified endpoints.

What security measures should be considered for API calls?

To secure API calls, developers should implement best practices such as using authorization tokens, encrypting sensitive data during transmission, and regularly updating security protocols.