Today’s software ecosystem consists of several applications, services and platforms. They need to communicate with each other to perform a complex task.
The reason for such a distribution is easy maintenance and a simpler architecture. Monolithic architecture often becomes too bulky to build and maintain. A distributed solution offers much ease of usage and safety.
A bug in an isolated application is much easier to handle than inside an embedded system and it also doesn’t jeopardise the overall software performance. To bind all the distributed applications, services, and platforms, an application programming interface is required. It is through these APIs that the different applications can communicate with each other.
APIs have their own lifecycle separate from the software. They need to be designed, developed, deployed, and maintained to perform consistently and accurately. These stages play a crucial role in ensuring APIs are scalable, reliable, and adaptable to evolving business needs.
Phase 1: API design
API design is the first stage put into reality after its idea conception. The design of the API is crucial in deciding how easily it can be developed, deployed and scaled. A poor design can cause cascading effects on its development, performance, security, and integration challenges. To achieve this, the most common methodology is API-first design. Developers design the API’s structure and functionality much before starting to write code.
Several tools can be used for designing API, like Postman, OpenAPI and RAML. These tools allow developers to define endpoints, request/response formats and authentication methods of APIs. These definitions can be created in a standardised and machine-readable format.
Design review is conducted at the initial stage, which involves all the stakeholders, developers, designers and testers, to come to a consensus. Once the design is approved by all stakeholders, it becomes easier to follow through the subsequent stages with the least friction.
Phase 2: API development
Once the design is finalised, developers start building the code. While doing so, they must keep a check on its consistency and scalability factors. APIs should have a simpler design and logic to be able to update later.
API often go through frequent updates due to evolving business needs. Hence, best practices for developing API should be followed that allow future-proofing and scalability with ease. These best practices include modular design, standard naming conventions and clear documentation. Version control should also be taken care of using tools like Git.
As soon as the development is done, unit and integration tests must be performed. They ensure that APIs work correctly as a standalone function and cohesively in a system. Constant reference to the design must be followed while developing the code. It prevents “API drift” during development that can have cascading effects on the later stages.
Designs are usually approved by multiple stakeholders who come into play at different stages. Developing the code as per the common consensus prevents any friction between stages and maintains consistency throughout.
Phase 3: API testing
No matter how diligently the API was developed, it may fail if not validated properly. Testing APIs ensures they work perfectly in the real-time application. It is needed to check if the APIs work as per the requirements, are secured and handle errors gracefully. The four most important kinds of API testing are:
- Functional Testing: It checks all the basic functional elements against its expectations. Through functional testing, testers check if the API produces correct responses to valid input and handles errors as per the design.
- Performance Testing: This kind of testing is important to check how the API performs in different situations. Scenarios are simulated to check the API’s performance under load. Its scalability is checked while measuring metrics like latency and throughput.
- Security Testing: Checks for three parameters: authentication, authorisation and data privacy. Once these parameters are tested properly, it ensures that the APIs are safe to be used in real-world applications where safety is one of the biggest criteria.
- API Contract Testing: This is a special kind of testing specifically related to APIs. APIs are the interface between communication between systems. To do so, systems must come to a common agreement required for cross-communication. For this API, contracts are made that ensure consistency between separate systems. API contract testing ensures that systems do not fail during integration if the shared agreement is followed between the provider and the consumer.
Phase 4: API deployment
Deployment might not have been a greater challenge if it had needed to be done only once. But modern development methodology involves continuous deployment after frequent changes. This need has been taken care of well by modern containerization and orchestration tools like Docker and Kubernetes, respectively. They allow APIs and their dependencies to be packaged in a closed container that can run consistently across multiple environments.
Automated delivery in the modern CI/CD pipelines ensures development, testing and API deployment are done smoothly without human errors. Having a rollback plan in place allows for a quick reversal of the deployment should any error arise in production.
Phase 5: API monitoring
APIs usually work in crucial environments in production. Communication between systems is an ongoing process in real-time. Any breakage in the API can disrupt the flow and put the system to a halt. Hence, automated continuous monitoring is crucial for APIs. It allows them to function well and catch any bugs immediately before their effect ripples through the network of systems.
There are several API monitoring tools available, like Prometheus or New Relic, through which APIs can be monitored on their dashboards. These tools show metrics, like latency, usage trends and error detection.
While monitoring is important, there are several guidelines for API governance as well. This helps in deciding how APIs should evolve and what standards need to be followed. These guidelines are created based on the broader ecosystem of an organisation and the systems communicating with each other in it.
Closing statement
While creating APIs, there are several factors one must consider. An API-first approach that starts with the design and contract allows for consistent growth during its development. Automating API development, testing, and deployment is another useful solution to maintain accuracy and consistency across the systems.
If you want to design a resilient distributed system, mastering the APIs development methodology through all its stages is a must. It allows for proper planning, development, testing and deployment for APIs without creating any unnecessary hassles. Once the API lifecycle is properly defined, it can boost innovation and broader business growth where systems can communicate seamlessly.
