Application Programming Interfaces (APIs) are used daily in many ways. Whether in a business environment or using DoorDash after a late night at work, APIs and the benefits we reap from using them improve the quality of our daily lives.
As you become more familiar with APIs and enhance your understanding of them, you can add value to your organization by addressing an underperforming area or improving a process. Therefore, this article will discuss how to implement an API, how to use an API, the critical components of an API, and the common types, focusing on REST and SOAP APIs.
What is an API, and why does it matter?
APIs are essentially an intermediary between different applications, making it easier for them to talk to each other. They also allow businesses to communicate easily with external entities or third-party software, including various business intelligence tools. But there is more to APIs than basic interpretation.
Expert Tip
APIs fundamentally enable two software applications to communicate through established rules and protocols. They act as an interface, exchanging data between applications, accessing features or services from other applications, or creating a new application.
Additionally, APIs allow developers to easily integrate existing services or features from other applications without developing the service or feature themselves. By not having to build code from scratch, APIs increase development speed. They are also reusable for routine processes, although they are available only to authorized users.
Key components of an API
Building an API requires a set of programmable instructions that allow software applications to communicate. With these instructions, an API client initiates an API request to a server. Then, the API retrieves the requested data from an external server or program and returns it to the client.
In addition to retrieving data, APIs can invoke functions, send information back to a server for management and storage, or provide real-time data, such as pricing or availability. To successfully execute an API, the following components are required:
API client
The API client makes it easier for a person to use an API while hiding the complexities of the backend details. For example, a user clicking on a button, application, or service can trigger the API client, which works well for no or low-code development. An API client can also initiate an API request or an external event or notification from a service or application that automatically activates a request.
API key
A unique passcode containing letters and numbers that grants access to an API. These keys often authenticate an application or identify an authorized user.
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:
Endpoint
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.
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.
- POST – adds new data saved to a URL resource on a server; See Figure 3.
In the example shown in Figure 3, 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: used to partially update an existing URL resource with additional information
- DELETE: used to remove data from a database
Parameters
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 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.
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:
API server
The API server is software that resides directly on a server and sits between the client and the data source. For example, 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 response
The API server generates a response that is returned to the API client. This response can vary in multiple ways depending on the contents of the API request. Select the tabs to view the different types of information that an API response includes:
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 that the server returned the requested data, and Code 201 indicates that 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 provide additional information about the server’s response, such as metadata, instructions, and other details on the response 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 contains the data returned by the API server based on the client’s request. It typically includes structured data objects representing the requested resources, metadata, or potentially an error message indicating what went wrong if the request was unsuccessful.
Simple Object Access Protocol (SOAP) API
The SOAP API is another popular and more structured API that utilizes an Extensible Markup Language (XML) schema messaging format. The SOAP API also prevents unauthorized users from accessing critical data. In contrast, REST supports XML, JSON, plain text, and Hypertext Markup Language (HTML).
The processes of the REST API are also faster due to smaller messaging and available caching, while SOAP adheres to a rigid set of rules and messaging patterns, making it slower than REST. Since SOAP is significantly more secure than a REST API, it is the preferred choice for online banking and financial institutions.
By outlining the process of the SOAP API below, you can see how it is similar to that of a REST API client call:
Step-by-step guide on how to use an API
To implement an API, both applications must adhere to the established rules and protocols to communicate effectively. First, each party in the client-server relationship should fulfill its respective responsibilities. Then, the API created by a company must grasp its intended purpose and understand how customers submit requests to receive the desired response from the client.
The API documentation must clearly outline the endpoint, headers, data format, and corresponding parameter values. For each HTTP method, the client must accurately submit specific parameters and headers in the API request for the server-side application to respond successfully. API development begins with API documentation, and the created API undergoes multiple tests before going 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
Some initial questions you should ask yourself are: What is the goal of the 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
To develop the API, developers need to understand the requirements, the parameters included in the endpoint, the HTTP methods, and the data the API needs to access the database results. It’s also important to discuss error handling before creating a data model and determining the activities required to interact with the data sources.
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 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. Ask yourself, will the API improve business operations, enhance customers’ experiences, lead to more satisfied customers, or increase revenues? Then, define the API requirement with the original API strategy in mind.
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.
Expert Tip
The REST API is easy to use, faster than typical web services, and can return results using different data formats. It is also scalable due to its ability to cache data, which reduces the server load. Additionally, it can use SSL encryption for data transmission, which removes the threat of compromise.
6. Choose an API authentication method
API keys, which can be sent in a query string or request header, are the typical authentication method for REST APIs. Another option is OAuth 2.0, which is best used when accessing user data in applications like Facebook and Google. Username and password are also options, but they’re considered the least secure.
7. Creating an API specification and developing API documentation
Numerous API tools are available to help keep your API application updated and well-documented. As the specifications for your API evolve to meet requirements, the documentation can also be updated automatically through an API documentation tool. You want your API documentation to be easily interpreted and understood by developers, and these tools enable you to onboard API developers and users quickly without needing 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 API documentation should reflect this new version by adding a simple v2 or v3 at the end of the documentation title.
9. API deployment and development
A good API tool minimizes some of the challenges of developing an API app by reducing development time and costs, identifying issues early, adding external features without writing new code, and simplifying integration with existing systems. Implementing a Continuous Integration/Continuous Delivery process to automate application deployment allows API apps to be deployed faster without human intervention.
10. Monitoring an API app
If your API application is functioning properly and meeting the expected metrics, the API has fulfilled the initial goal outlined in the API strategy. To ensure your API application continues to operate effectively, you can invest in API monitoring software to detect power or network outages, observe traffic spikes, track API error rates, identify latency issues, and measure API availability.
API Management and Monitoring
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. Automated API tools that help with API creation and tracking are essential for ensuring that the API developed during 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 development time if you know an application that can provide the information you require already exists. If you are unsure of an application, search GitHub, which provides links to all the available public APIs.
Expert Tip
Use multiple programming languages to develop and execute an API. But if you are not a programmer, 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.
Once you have found an API that meets your needs, review the API documentation for examples and list the objects, parameters, and endpoints needed to execute an API call successfully. The typical steps involved in using an API are:
In this example, a sports fan wants to catch up on all the sporting events during the weekend of November 11th. To do so, the fan must request an API key, which will be appended to an HTTP method. Once the fan has an API key, he must thoroughly read the API documentation. See 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.
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.
Once you understand how to use an API, you will see its numerous benefits, including saving time and money. However, learning about backend data models, API integration, workflow automation, and page builders will require patience for non-programmers.
If you don’t have a background in programming, no-code platforms are designed for non-technical business users to develop applications without coding. Platforms like NoCodeAPI are explicitly created for this purpose and offer a marketplace of platforms like Google to Hubspot that you can use to set up an API.
What does an API do?
APIs serve various functions depending on how you intend to use them. Generally, an API provides a gateway for one application to access the services of another application without requiring any coding. To understand what the API can do, the user must read and comprehend the API documentation, which includes examples of the available API requests.
In practice, APIs eliminate the complexities of backend logic for the specific application receiving the API request or call, helping businesses become more efficient and productive. For example, an API allows everyday users to quickly make mobile payments, book flights, access rideshare apps, or retrieve 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?
In the previous sections, I detailed the REST and SOAP APIs, but the chart below provides a succinct overview of some common APIs and how they work.
| REST | An API that supports client and server communication using the REST architectural style. |
| SOAP | A messaging protocol that allows applications to communicate using an XML format. |
| GraphQL | An API query language used to specify which data can be retrieved and returned from multiple data sources. |
| gRPC | Open source API that allows an application to pass data to a function in another program on the Internet. |
| WebSocket | API that supports two-way communication 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. |
API software recommendations
There is no shortage of API management software available on the market. However, you should select an API solution that aligns with your business needs. For example, if you are looking for an API software solution that protects your data, select an API platform focusing on security.
Along with security, other essential capabilities in an API Management Tool solution include API lifecycle management, API gateways, and a development portal, which are critical in a comprehensive API software solution.
Also read: Top API Integration Platforms
Frequently asked questions (FAQs)
An API, or Application Programming Interface, serves as a bridge, enabling various software applications to communicate and exchange data with each other.
To start using an API, you should first obtain an API key from the provider, understand the documentation for proper integration, and then implement API calls in your project’s codebase.
An example of an API is the Google Maps API, which allows developers to integrate Google Maps into their applications. This enables features like map display, location search, and route planning.
You access an API by sending a request to its endpoint URL using HTTP methods such as GET, POST, PUT, or DELETE, typically including authentication and required parameters.
You can open an API in your browser by entering the API endpoint URL directly into the address bar and appending the necessary query parameters and authentication tokens.
You trigger an API by making an HTTP request to the API’s endpoint using tools like cURL and Postman or by writing code in JavaScript, Python, or Java.
