APIs are increasingly shaping the tech ecosystem. Almost all modern applications now have an API endpoint that you can interact with.

APIs work as the middlemen, allowing you to build programmatic interactions between applications that people and businesses use daily.

However, not all APIs are suitable for integration and use. Terrible APIs that frustrate users do exist. The following is a guideline you can use to identify an API that suits your development needs.

1. Optimized API Call Time

Optimizing API calls involves reducing the response time of an API. This includes how quickly the API serves requests and sends responses. It also involves reducing the effect that high volumes of data have on the API speed.

An API response time impacts the user experience. Slow APIs frustrate the user and affect the performance of the application. A high-performing API should have a response time of less than one second.

As a developer, you can test the speed of any API using Chrome DevTools. Open the Developer Tools > Network, then access the API endpoint in your browser.

You will see a breakdown of the API performance based on status, type, size, and time. The time measures the speed of the API.

You can go further and analyze the API components on the same tab. Click on the endpoint. You will see a tab open with information about its components. These include details about the Headers, Response, and Timing.

You can now tell whether the API is fast enough for your application. There are other online tools you can use to test for API speed. The popular ones among developers are Postman and Swagger.

2. Has Onboarding Guides

A good API provides onboarding guidelines for users. The onboarding guide should familiarize you with the contents of the API. It explains the API's use cases and how to integrate them. The information may include its endpoint definitions, code snippets, and example responses.

RapidAPI's onboarding guide is a good example. The guide has everything users need to know to consume their APIs.

Onboarding guides should also include authentication information. It is essential to have a well-documented authentication process so you can easily start working with the API.

APIs use different ways to authenticate their users. The most common is using an API key. Each registered user gets an API key which they use to make calls. The API can have different authentication keys for different categories of users.

3. Has Clear and Concise Documentation

All technical content should be clear and concise. Clarity is especially vital for APIs. As a developer, you don't have time to wade through too much documentation, so look for APIs that make it easy to learn how to use them.

Documentation ensures users will have a good user experience. Experience is critical for increasing the adoption of the API. Well-structured documentation describes the endpoints, methods, and response options.

Good documentation has users in mind. These are people with no knowledge of the API. Therefore, all the information should use familiar words and phrases.

The documentation should include step-by-step examples and illustrations. These help you understand the concepts quickly. Below is an example of well-structured documentation from the Twilio website.

An API's documentation should follow strong guidelines. A good example of an API documentation guide is Tom Johnson's I'd rather be writing guide. It is a complete guide on how to structure and write API documentation.

4. Has an Interactive Console

A good API has a console where you can test the API. Testing an API's endpoints lets you see if it fits your requirements.

Interactive consoles create a playground for you to test the endpoints quickly. This is an advantage since it means you do not have to use other testing tools. Consoles are a good way of determining whether the API suits your development needs.

The RapidAPI website has a good example of an interactive console you can use to test API use cases.

5. Provides Usage Options

API documentation should make it clear whether it is free or not. You need to be aware of which plans are free and which require payment. Avoid complicated pricing plans and those with many limitations.

Good APIs have multiple plans to cater to different clientele. Information should be open about usage quotas and limits that come with each plan. RapidAPI has a clear pricing plan that includes basic free and paid company plans for its users.

6. Has Guides and Tutorials

Tutorials help users understand how an API works. They teach a beginner how to use the API practically. By following one, you should understand what to expect when you interact with the API.

The goal of a tutorial is to guide you to produce the simplest possible output with the system. An API tutorial can be a response to a request made on the API. It shows you how to use a language or framework to get a certain response.

Tutorials should include instructions on how to sign up for an account and generate API keys. Additionally, there should be instructions on how to send a request and check the response. A good tutorial will also have illustrations such as diagrams, infographics, and audio-visuals. These make it easier to understand the processes involved.

An example of an API with good illustrations is the AsyncAPI Initiative.

The assumption is that if you make a call on one use case using a tutorial, you will succeed in making other calls. It's a good idea to check whether the tutorials are correct.

Why You Should Use This API Guideline

APIs create opportunities to interact with applications all over the world. Identifying a good one will save the time you would have spent creating a feature from scratch.

APIs give you access to world-class applications with amazing features. To get a good API, you must consider aspects of the API that goes beyond the endpoints and the call methods.

A good API is fast and well-documented to inspire developers to interact with it. Follow the above guidelines and select the best API for your application.