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Application programming interfaces, or APIs, ensure the smooth integration of your product with your end-users’ software. That’s why your API development should follow the same best practices as any other important DevOps project. You’re likely familiar with the software development life cycle, or SDLC, which breaks coding projects down into small, repeatable stages that you cycle through over and over again until you retire your software. APIs also have a development lifecycle that helps you streamline the planning, development, testing, deployment, and retirement of your API.

But what are the API lifecycle stages, and how do they contribute to the success of your API development?

What Are the API Lifecycle Stages?

Though there’s no definitive API lifecycle model, we like to break API development into five key stages: planning, development, testing, deployment, and retirement. Each stage builds on the benefits of the previous one, and you’ll likely move through them multiple times for each new patch or version of your API. Let’s examine each of the API lifecycle stages in greater detail.

Stage 1: Planning

The planning stage is crucial to the success of your API. You need to create an API contract laying out all the functional and nonfunctional requirements – and you need to do this before you start development. This process, known as “document-driven development,” or DDD, is a core best practice for DevOps API lifecycle management.

During the planning stage, key project stakeholders should collaborate on documenting your requirements, features, and functionality. For example, you may want a representative from the customer support team to weigh in on the end-user experience or a compliance analyst to help define the data security requirements. This will give you a more accurate, end-to-end view of your project’s API lifecycle.��

Some of the things you should consider as you create your API contract include:

• Who are the desired end-users of your API? How do you address their needs and solve their pain points?
• What is the core functionality of your API?
• How will end-users access and use your API? Do you need to create an SDK – software development kit – so your customers have the tools they need to integrate your API with their software?
• How are you going to handle API lifecycle management?
• What KPIs should you track and how will you track them?
• What standards (versioning, request and response formats, return codes, and the like) will you use to ensure API consistency and conformance?

The planning stage of the API lifecycle both improves the quality of your end product and makes every subsequent stage easier.

Stage 2: Development

The next API lifecycle stage is the actual writing of the API code. In general, you want to apply the same DevOps principles to API development that you’d apply to any other software development project, like:

• Using an agile, iterative approach to break API development down into small and repeatable steps that can be completed in short sprints. This allows you to find and fix issues quickly, pivot on a dime when requirements change, and streamline the overall API development process.
• Fostering open and continuous collaboration between teams by breaking down informational silos, using DevOps source code management with version control, and encouraging questions and suggestions. This will help reduce bottlenecks and miscommunication in the API lifecycle as well as improve team morale.
• Integrating automatic testing as early and often in the API lifecycle as possible so you can quickly identify functionality, quality, and security issues in your code before it reaches the next stage. This is also a core component of continuous integration/continuous delivery (CI/CD), another DevOps best practice.

For the development stage to proceed smoothly, you must have a robust set of requirements for your developers to work off of. That’s why it’s so important to start with the planning stage before you move on to API development.

Stage 3: Testing

Testing, on the other hand, should not happen in the exact order we’re describing. As mentioned above, you should test your API code early and often, a process known as shifting left. Every iteration of API development should be tested for functionality, performance, user acceptance, security, and compliance. Doing so ensures that any issues are found and remediated before they affect later stages of development or even the finished build.

However, you can’t constantly pause development to run these comprehensive tests. That’s why test automation is so crucial to DevOps API development. Automated tests can run concurrently with other workflows and without human intervention, further reducing development bottlenecks as well as smoothing friction between your dev, QA, and security teams.

The testing stage verifies that your end product meets all the requirements and promises laid out in the planning stage. It should take place continuously throughout API development, which will result in a smoother deployment.

Stage 4: Deployment

After you’ve developed and tested your API according to your API contract, you move on to the deployment stage. It’s critical that you have policies and workflows in place for monitoring and collecting feedback on the performance and functionality of your released API. This should include application monitoring, collecting end-user feedback, assigning issues to the correct teams, and implementing fixes in the form of patches or updates.

In this stage, you can really see why we call this the API lifecycle – once you inevitably find problems to fix or optimizations that will improve your API’s performance, you’ll move back to stage one of the API lifecycle. Any updates or new versions will need to be planned, developed, tested, and deployed according to these same best practices.

Stage 5: Retirement

Eventually, after many updates and versions, you’ll need to retire your API. During the retirement stage of the API lifecycle, you need to provide your end-users with a thoroughly documented migration plan to your replacement product. Then, you need to monitor usage as your API reaches EOL (end of life), and if necessary, nudge stubborn users with repeated reminders about your migration path.��

Using the API Lifecycle Stages to Streamline Deployments

The API lifecycle stages help you streamline deployments by breaking down your API development project into small, iterative steps and including automation and collaboration as much as possible. The benefit of moving through the lifecycle over and over again is that you can use your ongoing experience to continuously improve and optimize both your processes and your finished releases.

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