Modern software development can take various development approaches, and the results can vary wildly. Even if the most visible end result is a user-facing application, the way that app functions and behaves in relation to its users, the underlying data sets, and the systems upon which it operates can be affected quite dramatically by changes in the development approach and areas of focus.

Below, we’re going to look at one of these approaches. API-first is a relatively simple concept, but it can significantly impact an organization’s digital strategy and development cycles. But what does it mean to build API-first? What are some strategies and best practices for doing so? What are the net benefits of building API-first? Let’s dive into this topic!

What Is “API-First”?

API-first is a relatively simple concept — put the development of the API and its eventual consumption model ahead of any other focuses and processes. For those accustomed to API development, this might seem common sense — after all, isn’t that how all applications are developed?

The truth is that development can start with many different focuses and intents. Some processes begin first with the business focus — what is the eventual thing that will be monetized to generate revenue? Others may start with the platform underneath — what is the current data set or user experience, and how would an API function across that? Many of these focuses can make sense given specific scenarios. Still, they miss a key value — API development based on the idea of what an API should be foundationally rather than as a reflection of another system.

Enter API-first development. API-first is the concept that an API, and its end consumption, should be the driving force behind development. API-first is the creation of a logical and consistent API from the get-go that is reusable, scalable, and extensible.

As we’ve covered previously, some examples of API-first design include:

• Creating an API before a website
• Creating an API before an app
• Creating an API before integrating with a system
• Creating an API before syncing with a database

Benefits of API-First

API-first boasts some major benefits. First and foremost, it enables amazing extensibility and scalability. Focusing on the consumption model itself in API-first development means that you’re already focused on creating logically consistent individual and consumable services and systems. This focus means you’re creating a system that is abstracted away from the underlying data, systems, and business logic. Doing this creates a system where new functions can be added, built, removed, and changed.

This focus on the API also ultimately reduces the cost of developing the API and sending it to the market. When an API is designed around its eventual consumption model, API iteration can quickly occur without worrying about the effects on the underlying data and systems. Quick iteration is unlocked by focusing solely on the API, thereby reducing time to market and decreasing overall development costs.

This additional flexibility also naturally results in an increased ability to pivot and adopt new strategies without the same costs you would incur by reinventing the wheel. This thereby results in greater business mobility, allowing for APIs to shift depending on underlying business needs in a way that, ironically, would be less easy to do if one were principally focusing on the business case.

It should be noted that API-first development also has some significant impacts on the development methodologies behind the development process. Adopting this modality means that teams are more able to move into agile development and away from waterfall development due to the nature of the construction process. When API development is agreed upon as a contractual model, independent teams can build for the API rather than for specific use cases and needs. This means that you can build multiple microservices at the same time as opposed to having to use a waterfall method.

Ultimately, the adoption of API-first results in better user experience, better developer experience, and a better API in most cases. When developing APIs, focusing too much on the underlying systems can result in an API that does what it needs to without really considering the person who will use it. Adopting an API-centric model resolves this issue, as the definition-centric API development process will result in better-defined and contextualized output that considers the end experience as a first and foundational concern.

Drawbacks of API-First

There are a few drawbacks to API-first development. Firstly, this approach does require abstraction away from the underlying data and structures. While this can be beneficial, in some cases, this can result in an API that functions well without consideration for what it functions atop. While this is more a case for cross-organization and source aggregation APIs, the issue is worth considering.

The nature of API-first also requires significant buy-in, especially from cross-organizational or cross-organizational unit groups. Since the heart of this development modality is contractural, all stakeholders must buy into that contract. Not every team may be able to work within such strictures and seemingly arbitrary rules. This is especially true when most of the units doing work don’t have direct interactions with the data sets or systems in question.

Finally, API-first can require much more lead time for understanding and planning. Developing with the end result in mind means you must be prescient and plan well. Considering what the end state looks like requires a lot of study and intentional work — given that this work should be done as part of the foundational approach to API development in general, it is not entirely appropriate to consider this a drawback as much as it is an important consideration.

Best Practices for API-First Design

Now that we understand what API-first development looks like, let’s look at some best practices for its general application.

Know Your Purpose and Design

Since API-first requires that developers know what the API is supposed to do and how it is meant to function early in the process. Understanding the API’s purpose and then defining its end state is the major first step of the development cycle and should be given the focus and importance it requires.

This can take a wide variety of forms. This process can look like a simple review of the underlying purpose and business logic, or it can take a more complicated form through an end-to-end audit of the user personas and use cases that will function upon the API.

Plan for Alternate Use Types

Likewise, developers should understand that the API, even once completed, may take different forms depending on the end-user and the scenario it’s being used in. Edge APIs might be exposed differently than domain APIs, and internal APIs fundamentally differ from partner or external APIs, and so on. API-first development must thus take into account these varying circumstances.

Understand the Underlying Layers

API-first does not mean an API developed with tunnel vision. Having a holistic view of an API means that you have to understand the underlying systems and understand how they connect to the API itself. This requires having an understanding of the data, the interconnected systems, and the transit layers, as well as their potential strengths and weaknesses. This also necessitates having a developer vision of who will use the service.

Document Comprehensively

Document everything. API-first is the creation of an API based on the understanding of the developers creating the API. Necessarily, this contract must be well-documented to share knowledge. Accordingly, adopting a high-documentation approach is paramount to long-term success. This documentation should be comprehensive and demonstrate sample code.

Conclusion

Ultimately, API-first is only one of many development paradigms. Adopting API-first can unlock significant benefits for most developers, but it requires investment, awareness, and readiness. APIs are only becoming more ubiquitous and critical to the success of businesses across the planet — adopting an API-first development modality can help unlock this success and catapult it to new heights.

What do you think of API-first development? Let us know below!