Application Programming Interface (API) services are interfaces that provide a program with a description of how to interact with a system in order to retrieve and/or change the data within it. Some well known bloggers describe APIs as next big wave in Software as a Service (SaaS). API as a Service is, in essence, a software platform that allows users to interact with third-party APIs as well as manage their own custom APIs.
Generally, API belongs to software development, but we created a separate page because of our exceptional and rich experience in API. We did and participated in almost every activities related to API technologies:
Learn Customer Requirements
First of all, we learn what business capabilities the API exposes to its consuming clients and what data and functions it can provide to API users. Also, we discus issues of the security, access level, user roles, Expected API performance and response time.
Finally, in this stage we specify which tools and resources are necessary for API development.
Design API
API design process is very important. It specifies API quality and usability. The following steps are typically taken when designing an API:
- Figure out use cases and what audience will have an API. Particularly, what kind of development project will integrate the API and which users will use it?
- Specify API layers. For example, client, validation, caching, business logic, etc.
- Determine potential endpoints and start designing a potential implementation.
- Show the API project to a customer and discuss with him the details.
API Development
The next step is API development. Usually, we use appropriate tools to build API architecture at this stage: Swagger Tools, Stoplight Studio, etc. Modeling languages are: YAML or JSON.
Simultaneously, we make documentation with the above mentioned tools. In order to get feedback from the developers or user testers, API files are uploaded to appropriate servers: SwaggerHub, Readme.com, etc. It depends on our agreement with the customer.
In the development stage, we will define all the API responses, handle exceptions and errors, implement searching and pagination, etc.
After finishing the API architecture, comes the business logic. This is the phase where we convert the human-readable API design layer into actual code and business logic. We can work with different programming languages and frameworks: C# and .NET Core, Node.js, PHP, Java—it depends on our agreement.
Finally, after implementing business logic, we’ll make the final version of the documentation.
API Testing
Testing of the finished API project is done using different tools: Postman, Katalon, C# with xUnit or NUnit, Java with Junit and TestNG, PHP with PHPUnit, Node.js with Cypress, etc.
The API tests include tests for the isolated functions, realistic data and realistic results, evaluation of the various network conditions, and simulation of the errors.
API deployment and Monitoring
After deploying production on an API gateway, we’ll monitor different parameters of API performance and results.