November 30, 2023

How to Use an API: Just the Basics

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Key takeaways

  • API documentation must be thorough and understandable for the user and external developers.
  • Business or mission-critical API applications that must remain operational 7/24 can use API monitoring software to alert a designated person within 3 minutes of an API incident.
  • A learning curve will be associated with learning how to use a no-code API platform, which will require patience.

Application Programming Interfaces (APIs) are used daily, particularly if you have a mobile device. The weather application, PayPal, banking apps, Facebook, and Instagram all use APIs. In this article, we will cover how to implement an API, how to use an API, the critical components of an API, and the common types of APIs.

What is an API, and why do they matter?

APIs serve as a software intermediary, allowing two applications to talk to each other. However, they can also do much more. 

APIs allow two software applications to communicate using pre-established rules and protocols. The API serves as a software interface for the two different applications that need to communicate. The API can pass data back and forth between two applications, access the features or services of other applications, or create an application. 

APIs are essential because they allow developers to easily integrate existing services or features from other applications without actually developing the service or feature. APIs increase development speed by not having to develop code from scratch, and the APIs are reusable for routine processes that are available for authorized users. 

They also allow businesses to communicate with external entities or use third-party software easily, including using various business intelligence tools.

Key components of an API 

Building an API requires a set of programming-based instructions that allow software applications to communicate. An API client initiates an API request that goes to a server. The API retrieves the requested data from an external server or program, which is returned to the client. Besides retrieving data, APIs can also trigger functions, transfer information back to a server for management and storage, or return real-time information, such as pricing or availability. To successfully execute an API, the following components are needed:

API client

A user can be an API client that initiates an API request, or a request is automatically activated by an external event or notification from a service or application. The API client can be triggered by a user clicking on a button, application, or service. The API client makes it easier for a person to use while hiding the complexities of the backend details.

API key

A unique passcode containing letters and numbers that grants access to an API

API requests

An API request is a message sent to an application asking a server for information or a service. The Representational State Transfer (REST) APIs are commonly used, so we’ll discuss what is involved in a REST API request. The sub-components or parameters that make up an API requests are:


An endpoint is a dedicated Uniform Resource Locator (URL) that points to the location of a resource on a server. The API endpoint allows different systems and applications to communicate by sending and receiving information with instructions. See Figure 1.

Example of an API endpoint.
Figure 1.

Request method

The request methods are the specific operations the client wants to perform on the URL resource. REST API uses the HTTP method that can perform the following actions:

  • GET – retrieves data from a server; see Figure 2.
Example of a method used in an endpoint.
Figure 2.
  • POST – adds new data saved to a URL resource on a server; See Figure 3.
Example of a method used in an endpoint, POST.
Figure 3.

In the Figure 3 example, the good_comment phrase in the Body field will be posted as a new comment in the URL resource.

  • PUT – replaces an entire resource with new information
  • PATCH – is used to partially update an existing URL resource with additional information
  • DELETE – used to remove data from a database 


Parameters are the variables passed to an API endpoint to provide explicit instructions for the API server to process. The parameters can be included as part of the API request in the URL query string or in the request body field, as shown in Figure 3. In Figure 4, notice how the parameters are included in the HTTP endpoint URL sent to an API server on a web server.

Example of what a typical GET API will resemble.
Figure 4.

Request headers

The request headers provide essential information for a server to process the request, and the header information is in the message body. Headers give the following information:

  • Specifies the format the data will be sent in, such as the JavaScript Object Notation (JSON) format
  • Identifies the API version to call
  • Provides an API key for authentication
  • Dictates the behavior of the server in handling the request
  • Provides metadata information about the request or response
  • Contains information about the request method used
  • Includes information on the content type of the requested payload

API server

The API server is software that resides directly on a server. The API server sits between the client and the data source, so web APIs sit between a user application and the web server. Once an API client creates an API request, the request goes to the appropriate endpoint on the API server for processing. The API server handles authentication, validates the inputted data, retrieves or manipulates the data from a database, and returns the appropriate response to the client. See Figure 5

API server flow.
Figure 5.

API response

The API server generates the API response that returns to the API client. The API response can respond in multiple ways depending on what was in the API request. An API response provides the following information:

Status code

The status code informs the client of the results of the submitted API request. The codes help the client understand what happened with the request. Code 200 signifies the server successfully returned the requested data, and code 201 indicates the server successfully created a new resource. The code 404, which we have probably all experienced, means Not Found, so no action was taken by the server.

Response headers

Response headers provide additional information about the server’s response. Response headers can provide metadata, instructions, and other information about the response back to a client. A cache-control header lets the client know how long the data can be stored in a cache, and the set-cookie header is a cookie in the browser used for session management or authentication.


The response body is the data that is returned by the API server based on the client’s request. The body typically includes structured data objects representing the requested resources, metadata, or possibly an error message indicating what went wrong if the request was unsuccessful. 

Simple Object Access Protocol (SOAP) API

The SOAP API is another popular API used, and it’s more structured using an Extensible Markup Language (XML) schema messaging format. SOAP can only use the XML format, while REST supports XML, JSON, plain text, and Hypertext Markup Language (HTML). The REST API processes are faster due to the smaller messaging and available caching, while SOAP follows a rigid set of rules and messaging patterns, making it slower than REST. Since SOAP is far more secure than a REST API, it is the preferred API to use in online banking and financial institutions. The SOAP API process is similar to the REST API client call:

  • The SOAP client creates a valid XML document
  • The SOAP client sends the XML document to a SOAP server
  • The SOAP request is posted using HTTP to a SOAP request handler running a servlet application on a web server.
  • The API takes a SOAP request from the API caller and uses it to make its request to the SOAP service
  • The response is returned to the SOAP request handler and transferred to the requesting client.

The SOAP API prevents unauthorized users from accessing critical data.

Step-by-step guide on how to use an API

To implement an API, the two applications must follow the established rules and protocols so they can communicate with each other. The client-server relationship requires both entities to fulfill their respective responsibilities. The API developed by a company must understand the goal of the API and how customers submit API requests to get the desired response back to the client. 

The endpoint, headers, data format, and any associated parameter values all must be clearly defined in the API documentation. For each HTTP method, the client must correctly submit specific parameters and headers in the API request for the server-side application to respond to the API request successfully. API development starts with API documentation, and the created API is tested multiple ways before it goes into production.

To implement a successful API application, you need to follow a similar step-by-step process:

1. Develop an API strategy to deliver business profit or value 

What is the goal of the purported API application a business wants to develop? Will the API increase revenues, enhance operational efficiency, or use existing data or technology to generate additional revenue?

2. Designate a data source for the API and create an API diagram

Create a data model and the activity required to interact with the data sources. To develop the API, the developers must know the requirements, what parameters must be included in the endpoint with the HTTP methods, and the data the API needs to retrieve the database results. You will also want to discuss error handling.

3. Assess your business network

Assessing your business network will help you select an API solution that can easily integrate within your network and software resources. You can seek an integration specialist to ensure your chosen API solution works well with your existing business hardware and software resources.

4. Define API requirements

The expectation of what the API should do must be clearly defined. The API requirement must be tied back to the original API strategy. Will the API improve business operations, enhance customers’ experiences, leading to more satisfied customers, or increase revenues? 

5. Select an API data exchange architecture

There are multiple types of APIs, but this article only covered the two most popular, REST and SOAP. This article focuses on the REST API. The REST API can meet typical business needs because it requires less coding to complete a task, and the structure and logic are less rigid than a SOAP API. The REST API is easy to use, faster than typical web services, and can return results using different data formats. REST APIs are scalable due to their ability to cache data, which reduces the server load, and they can use SSL encryption for data transmission, which removes the threat of being compromised in transmission.

6. Choose an API authentication method

REST APIs’ typical authentication method are API keys, which can be sent in a query string or request header. Another option is OAuth 2.0, and it’s best to use this security option when accessing user data in applications like Facebook and Google. The username and password are options, but they’re considered the least secure.

7. Creating an API specification and developing API documentation 

An abundance of API tools are available to help keep your API application updated and documented. As the specifications for your API change to meet requirements, so does the documentation that can automatically get updated using an API documentation tool. You want your API documentation to be easily interpreted and understood by developers, allowing them to quickly onboard API developers and users without assistance from your development team.

8. Keeping the latest API updated with API versioning 

You want your users and developers to know when a new API is released. The easiest way to do this is to make it a part of your endpoint with a “ver1” or “ver2” added on the end of the URL path. As your API app is updated, the documentation needs to reflect a new version has been released. Showing a new version has been released in the API documentation can be done by adding a simple v2 or v3 at the end of the documentation title.

9. API deployment and development

A good API tool will minimize some of the challenges of developing an API app. An API tool will reduce development time and cost, identify problems early, add external features without writing new code, and make it easier to integrate with existing systems. Using a Continuous Integration/Continuous Delivery process to automate application deployment gets API apps deployed faster without human intervention.

10. Monitoring an API app

You have created an API application that is properly functioning and meeting the expected metrics, indicating the API has met the initial goal outlined in the API strategy. To ensure your API application is continuously working, you can invest in API monitoring software to detect power or network outages, see spikes in traffic, track API error rates, scan for latency issues, and measure API availability.

The goal of monitoring API software is to minimize downtime by addressing issues before they escalate, identifying issues that may impact the API’s performance, and resolving any problematic issues that could affect the customer negatively or cause potential revenue loss.

The full implementation of a successful API involves multiple steps that become the foundation for your API app. Even though the development and deployment processes are undoubtedly critical in building and running an API, you want to ensure that as long as the API is online, it’s performing optimally. Therefore, implementing an API entails constant monitoring and applying practical updates as business processes evolve. The automated API tools that help with API creation and monitoring are essential in ensuring the API developed in the API implementation process constantly meets the intended goals outlined in the API strategy.

Also read: 5 Capabilities an API Management Tool Should Have

Guidelines on how to use an API

Using an API can save you development time if you know an application that can provide the information you require already exists. 

If you are not sure an application already exists, you do a search on GitHub that provides links to all the public APIs available. Once you have found an API that meets your needs, you must review the API documentation. The documentation will provide examples and list the objects, parameters, and endpoints needed to execute an API call successfully, so thoroughly reading the API documentation is necessary. 

EXPERT TIP: You can use multiple programming languages to develop and execute an API. But if you are not a programmer, you should consider an API hub platform like RapidAPI that offers several categories of already-created API products or a no-code API builder like Xano or Zapier that allows you to build an API from scratch.

The typical steps involved in using an API are:

  • Look for an API that will meet your needs
  • Understand the API terms for using
  • Read the API documentation so you can test the API
  • Request an API key
  • Using the API documentation to make an API request
  • Interpret the API response to see if it meets your needs.

In this example, a sports fan wants to catch up on all the sporting events during the weekend of November 11th. The fan must request an API key that will be appended at the end of an HTTP method. Once the fan has an API key he must thoroughly read the API documentation. See Figure 6.

API documentation.
Figure 6.

The documentation lets the user know how to select a country and a specific category, like business or sports. After thoroughly reading the API documentation, the sports fan created this API request. See Figure 7.

API request creation.
Figure 7.

The results of the Get method return seventy different sports articles in the United States that include possible trades in baseball, National Football League (NFL) game results on November 11th, and college basketball and football results. See Figure 8.

GET method results.
Figure 8.

Once you understand how to use an API, the numerous benefits include saving time and money. Learning about backend data models, API integration, workflow automation, and page builders will require patience for non-programmers. The no-code platforms are designed for non-technical business users to develop applications without doing actual coding. The NoCodeAPI platform is explicitly created for non-technical business users to build API applications.

What does an API do?

Application Programming Interfaces are used every day in a multitude of ways. The API creates a gateway for one application to use the available services of another application without actually doing any coding development. The API user must read and understand the API documentation, including examples of the various API requests available. 

EXPERT TIP: All APIs remove the intricacies of backend logic for the specific application receiving the API request or call, which helps a business become more efficient and productive. An API allows everyday citizens to quickly execute actions, such as making mobile payments or flight reservations, accessing rideshare apps, or retrieving the latest weather information.

All APIs remove the intricacies of backend logic for the specific application receiving the API request or call, which helps a business become more efficient and productive. An API allows everyday citizens to quickly execute actions, such as making mobile payments or flight reservations, accessing rideshare apps, or retrieving the latest weather information.

Overall, APIs improve businesses’ productivity and our personal lives in numerous ways. 

What are the types of APIs, and how do they work?

The REST and SOAP APIs have been reviewed. The other type of API is GraphQL, which can use one API call that can return data from multiple data sources, and the other is gRPC open-source API, which allows an application to pass data to a function in another program on the Internet. The WebSocket API is another type of API. A WebSocket API is bidirectional in communicating between a user’s browser and a server. A client can send a message to a server, and the service will respond with a message back to the client. The service on a server can send information back to a client without the client making an explicit request.

API software recommendations

There is no shortage of API management software available on the market. Every API solution does something better than its competitors, so you must select an API solution that aligns with your business security posture if that is a priority. Therefore, if you are looking for an API software solution that protects your data, select an API platform focusing on security. 

Along with security, API management software features several capabilities that you may find helpful as you create, update, and manage APIs during an API lifecycle. Other essential capabilities you want in an API Management Tool solution are features such as API lifecycle management, API gateways, and a development portal, which are must-have features included in a comprehensive API software solution.

Also read: Top API Integration Platforms

APIs make the world go ‘round

APIs continue to grow, and the benefits we reap from using them improve the quality of our daily lives, whether in a business environment or using DoorDash after a late night at work. As you become familiar with APIs and understand them better, you can add value to your organization by addressing an underperforming aspect of a business or improving a process, making the organization more efficient. 

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An API, or Application Programming Interface, acts as a bridge allowing different software applications to communicate and exchange data efficiently.

To use an API, you typically need to obtain an API key from the provider, understand the documentation for proper integration, and then implement API calls in your project’s codebase.

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