by Jeremy H
• November 13, 2020
Ever since Roy Thomas Fielding introduced the world to the concept of REST (representational state transfer) and RESTful systems in 2000, developers have been using REST APIs in their web development projects with an increasing level of frequency. That being said, it wasn’t until the last decade that programmers began to embrace the idea of “API-first” development.
Today, the API-first approach to app development is more popular than ever, but what does the “API-first” mean exactly?
In this brief guide, we’ll help you understand the concept of “API-first development” and its tremendous advantages. We’ll also outline the most important steps for implementing an API-first development strategy in your next projects.
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The API-first approach to app development is exactly what it sounds like. It’s a development approach that considers application programming interfaces (APIs) before anything else. Essentially, the API-first approach recognizes that the consistency, reusability, and quality of your API ensures the following:
The API-first approach recognizes that the programming process should begin with planning the API. Then, each step of the API-first coding process will seek to preserve the initial API plan while ensuring the API’s consistency and reusability.
API-first development achieves consistency and reusability by using an API specification language that other developers can easily understand and navigate. The most widely-used API specification language is the OpenAPI Specification (originally called the Swagger Specification). While other API specification languages exist – like RAML and API Blueprint – OpenAPI has become the de facto “standard.”
Here’s how Swagger describes the OpenAPi Specification: “An API specification provides a broad understanding of how an API behaves and how the API links with other APIs. It explains how the API functions and the results to expect when using the API. A good example of an API specification is the OpenAPI Specification. You can view the latest version of this specification (3.0.1) on GitHub.”
To conclude this section, API-first means that you will plan how the API is going to behave before you start coding the application. It also means that you will commit to a consistent and reusable API specification before coding the application. This means that the form of your application – and the coding process – will reflect the API (and not the other way around).
From a workflow perspective, API-first requires you to invest more energy ahead of time into planning the API. Although this requires additional collaboration between developers, future API consumers, and key stakeholders, it helps ensure a more adoptable, developer-friendly, and compatible product.
The API-first approach to application development is currently growing in popularity because it supports the trend toward “microservices application architectures.” Over the last decade, the microservices architectural style made it possible for enterprises – like Amazon, Netflix, Uber, and Etsy – to achieve unprecedented scalability, growth, and competitiveness – while absolutely dominating their industries. Considering the success these organizations have achieved through API-first and microservices-based application strategies, it’s not surprising that other businesses are following suit with microservices strategies of their own.
The popularity of microservices as a trend can be seen in a 2020 microservices adoption survey by O’Reilly:
While the trend toward microservice is clear, not everyone knows what a microservices application architecture means. So let’s see how microservices thought-leaders James Lewis and Martin Fowler describe the concept: “The microservice architectural style is an approach to developing a single application as a suite of small services, each running in its own process and communicating with lightweight mechanisms, often an HTTP resource API [i.e., a REST API].” (Make note of the bolded text here; we’ll address it in a moment).
Ultimately, the microservices architectural style is a radical departure from traditional monolithic applications. A monolithic application consists of all services and features written into a single piece of code. Conversely, the microservices-based system breaks the monolith into its component services/features, and it runs each feature as an autonomous mini-application (or microservice). Ultimately, the individual microservices that comprise the architecture rely on REST APIs to interact with each other. Through loose REST API connections, the microservices connect to form the larger application.
As you can see, APIs are essential to microservices-based app development. Therefore, the growing popularity of microservices-based apps has led to a corresponding rise in API-first development strategies.
Now more than ever, modern developers need to consider first-and-foremost the APIs that their web services, apps, microapps, and microservices will expose. By planning the API first – and making sure it adheres to a consistent, reusable, and widely-understood API specification – developers ensure that their apps and services can easily integrate with virtually any microservices-based architecture.
The API-first approach (1) helps developers reap the benefits of microservices-based applications, and (2) helps developers ensure that their apps/services can be consumed by the widest range of clients/systems in the API economy.
Here are some of the most compelling advantages of API-first:
The loose connections of APIs ensure that the services they expose are as stateless and RESTful as possible. REST APIs allow for “loose” connections while minimizing or eliminating dependencies. This supports scalability because it’s easier to deploy, replicate, and destroy instances of a specific microservices app component in response to fluctuating demands on the system.
Well-designed APIs – and the fact that they promote app/client interactions without dependency – support pluggable, component-based architectures. This pluggability offers the flexibility to add, remove, or upgrade individual services/features while reducing the chance of impacting other parts of the system.
A microservices-based system that integrates through APIs allows you to build a highly-available and fault-tolerant system. This is because it’s easier to load-balance incoming requests, automate the deployment of microservices, achieve redundancy of key components, and carry out other orchestration strategies. Through the redundancy of systems and other fail-safes – like implementing circuit breaker patterns – if one microservice fails, there is less chance of it negatively impacting the rest of the system.
APIs offer a language and platform agnostic interface that different microservices can interact with. Because API-first development prompts the creation of consistent and reusable APIs, the API-first approach helps your systems integrate with a wide range of services – regardless of their languages and platforms.
The pluggability that API-first achieves means that development teams can re-use different app components (or microservices) in other projects. Development teams can focus more time on building a minimum viable product, then complete the rest of the project by integrating with the APIs of other pre-built microservices components. An API management solution like DreamFactory is indispensable in this regard because it allows you to instantly integrate a wide range of features and services into the projects you’re developing.
Implementing an API-first development approach in your organization requires planning, cooperation, and enforcement. Here are some key tasks and concepts to build into your API-first strategy to make sure it’s a success:
Determine who the API stakeholders are inside your organization, and determine who the consumers of the API will be. Before and during the API planning stage, collaborate closely with these individuals to ensure that (1) stakeholders/consumers will have the easiest time using the API, and (2) the API is designed to satisfy their unique use-cases.
Brainstorm the key functions and services that the API needs to expose before starting to code. Based on collaboration with stakeholders and API consumers, what key features/capabilities are needed? Make sure to understand the different use-cases for the API, confirm these with stakeholders, and determine the API end-points required to service those needs.
The API contract codifies the standards and best practices that you will adhere to when building the API. At this stage, you should design and document the API in a way that ensures compatibility with APIs and adherence to consistent and reusable standards. We recommend that your REST APIs adhere to the OpenAPI standard since it is the most widely used.
An API style guide ensures that the different teams in your organization use the same consistency and reusability standards for all APIs. For example, the API style guide should codify the API status codes, error handling, versioning strategies, and other aspects of your APIs.
Use API governance to enforce the API standards that you establish in the style guide. Enforcing your established standards may involve peer reviews of both the APIs themselves and the application code.
Automate your API generation processes with DreamFactory. The DreamFactory API management platform includes tools that help you automatically generate REST APIs for nearly any service or database – in just a matter of minutes. Best of all, DreamFactory generates APIs with full Swagger documentation, and they adhere to the OpenAPI standard. Swagger documentation is also interactive, so developers can explore and test the API endpoints before integrating your API into their systems.
After reading this guide, you should have a clear understanding of what API-first development is, and why it’s essential to modern, microservices-based application development. You might even want to try adopting an API-first development strategy of your own.
Whether you’re already an API-first developer – or planning to adopt this strategy in the future – the DreamFactory API manager can facilitate your API-led development journey while reducing your labor costs and dramatically speeding up your time to market. Not unlike an “API Swiss army knife,” DreamFactory’s API portfolio allows you to instantly integrate useful tools, features, and services into your applications and IT infrastructure projects. Moreover, DreamFactory’s automatic API generation features empower you to generate fully-documented REST APIs for virtually any database or system in minutes.
If you’d like to learn more about DreamFactory and how it can speed up your time to market while supporting your API-first development goals, contact the DreamFactory team now!
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