APIs, or application programming interfaces, have been around for nearly 20 years and have evolved from being the hidden bridge that connects multiple software programs to the building blocks of the modern software development process as developers and businesses started to follow the API first approach. 

In this article, I will answer some of the most asked questions, such as: what exactly is API's first approach? Why should you consider adopting this approach, what challenges you might face, and how to tackle them. 

So, let’s get started. 

What is API First?

API first, or API first approach, is all about prioritizing APIs at the beginning of the software development process, a.k.a positioning APIs as the building blocks of software. API-first organizations develop APIs before writing any other code instead of treating them as afterthoughts. This approach lets teams construct applications with internal and external services delivered through APIs.

How API First Works

To understand how the API first approach works, you need to have a forward-thinking mindset, recognize the role of public, private, and open APIs in your organization, and understand the API lifecycle and toolings. 

We will get into each of these later in the article, but to answer your ‘how,’ here’s a simplified step-by-step approach you can follow: 

1. Define Requirements: The first step is to gather requirements from stakeholders and potential API consumers to understand their needs and use cases.
2. Design APIs: Create a detailed API specification using tools like OpenAPI. Define endpoints, data models, error handling, and security measures.
3. Mock and Test: Use API mocking tools to create a prototype of the API. It allows testing your API without the need for a fully implemented backend. For more on testing, check out API Testing Challenges.
4. Develop: Once the design is validated, the API and the underlying application will be developed. Frontend and backend teams can work simultaneously using the API specification as a guide.
5. Document: Maintain comprehensive and up-to-date API documentation. Include examples, usage guidelines, and necessary details for developers to use the API effectively. Discover Treblle’s API documentation feature, reviewed by Phil Sturgeon, for insights into its industry-standard capabilities.
6. Versioning: Implement versioning to manage changes and updates to the API without disrupting existing consumers. For more details on this, visit API Versioning: All You Need to Know.
7. Track Performance: Monitoring your API’s performance and usage is crucial. Explore how API-first teams do this with How API-First Teams Track API Performance.

 API-First vs. API Design-First

As mentioned above, API first is all about prioritizing APIs as the most important element of the software development process. API-first organizations develop APIs before writing any other code instead of treating them as afterthoughts.

API design-first means describing every API design in an iterative way that both humans and computers can understand, even before writing any code. With an API design-first approach, every team uses the same tool, speaks the same language, and uses the same predefined nomenclature. 

Here’s a side-by-side comparison of both approaches to give you a better understanding: 

Both API-first and API design-first approaches get stakeholders involved in the early design process, even before writing any code, which provides several advantages over the conventional code-first approach, such as:  

• Ability to Work in Parallel – Since your team documents everything from the initial phase, you can create mock APIs and test them locally to see if they function as planned without waiting for other teams to complete different phases of the API.
• Ensure a Positive Developer experience – You can use API description documents and third-party API documentation tools to automatically generate things like interactive documentation, client libraries, and SDKs that improve the developer experience,
• Reduce Development Costs – Since one API can be reused for several sections of the application, developers don’t need to spend time recreating each one of them. Additionally, fixing APIs in the design phase is much more affordable than fixing a coded one.

Benefits of API First Approach for Developers

1. Improved developer experience

API-first approach provides clear, well-documented interfaces for developers to work with. This makes it easier for them to understand how different parts of the system interact, reducing confusion and improving productivity.

2. Parallel development for different teams

With defined APIs, frontend and backend teams can work simultaneously without waiting for each other. Frontend developers can use mock APIs while backend teams develop the actual functionality, speeding up the overall development process.

3. Enhanced software quality

By focusing on API design upfront, teams are forced to think through the system's architecture and functionality more thoroughly. This often leads to better-designed, more robust software with fewer integration issues.

Benefits of adopting API-first for Businesses 

1. Reduced app development costs

Once established, APIs can be reused across multiple projects or platforms. This reusability reduces redundant work and lowers development costs for future projects.

2. Tech stack flexibility

APIs provide a layer of abstraction between different parts of a system. This allows teams to choose or change technologies on either side of the API without affecting the other as long as the API contract is maintained.

3. Faster time-to-market

The combination of parallel development, improved quality, and reusability often results in faster development cycles. This allows companies to launch products or features more quickly, gaining a competitive advantage.

4. Better interoperability

Well-designed APIs make it easier to integrate with third-party services and other systems. This improves the overall ecosystem of your software and can lead to more robust, feature-rich applications.

Challenges of Implementing API-first Approach

1. Needs Cultural Change

Transitioning to an API-first mindset is not just a change in strategy but a shift in how development teams operate. Instead of jumping straight into coding, teams must start by designing and agreeing on API contracts upfront. This demands a collaborative approach, where frontend and backend teams work closely together from the beginning. It's about individual teams and the entire development community coming together to build better software.

2. Navigating Regulatory Compliance Adds Complexity 

APIs often expose data and functionalities that must adhere to regulatory and governance standards (GDPR, HIPAA, etc.). Ensuring that APIs are compliant adds an extra layer of complexity. Developers need to stay informed about the relevant regulations and design APIs that meet these requirements, which can be challenging when dealing with sensitive data or international markets.

3. Integrating with Legacy Systems

Legacy systems can be a significant obstacle in an API-first approach. Many older systems weren't built with APIs in mind, making it difficult to create seamless integrations. Developers may face challenges like outdated technologies, lack of documentation, or incompatible data formats. 

Are you an API First Company? 

If your answer is ‘yes’ to all of these questions mentioned below, then you are an API First company: 

1. Do you have most of your data flowing through APIs? 
2. When developing software, do you design or think about APIs before defining anything else? 
3. Do you share public or partner APIs? 
4. Do you know how to discover your APIs?
5. Do you have SOPs in place to build APIs?
6. Do your APIs meet regulatory requirements?
7. Do you see the security risk to your API perimeter?

If you failed to answer yes to any of these questions, read the following section to know more: 

How To Become API First

Here are a few initial steps you should take to become API first:

1. Adopt an API-First Mindset

Ensure that everyone in your organization understands the importance of APIs and how they can drive business value. This involves prioritizing APIs as the starting point for all projects Instead of building features and adding APIs later, training, and workshops to get all teams on board with the API-first approach.

2. Define Clear API Standards

Develop standards and best practices for API design, development, and documentation. This might include conventions for naming, versioning, security protocols, and error handling.

3. Foster Cross-Functional Collaboration

Break down silos between teams and Involve API consumers (both internal and external) in the design process to ensure the APIs meet their needs and are user-friendly.

4. Implement API Management and Governance

Adopt API management platforms like Treblle, Apigee, Postman, or Kong to manage your APIs effectively. These tools can help your teams with monitoring, versioning, security, and analytics. For a deeper dive into best practices for API governance, check out this guide on API governance.

API First Code Example

Let's look at a simplified code example to illustrate how an API might work. We will take a basic API that allows users to create and retrieve to-do list items.  

Here's a possible design for the API:

• Endpoint: /api/todos
• Methods:
  • GET: Retrieves a list of all to-do items.
  • POST: Creates a new to-do item. The request body should contain the text of the to-do item.

Here's a Python code snippet demonstrating how a client application might interact with this API:

import requests

response = requests.get("http://your-api-url/api/todos")

todos = response.json()
for todo in todos:
  print(f"- {todo['text']}")

new_todo = {"text": "Buy milk"}
response = requests.post("http://your-api-url/api/todos", json=new_todo)

if response.status_code == 201:
  print("To-do item created successfully!")
else:
  print(f"Error creating to-do item: {response.status_code}")

This is a very basic example, but it demonstrates the core concept of an API.  The client application (here, a simple Python script) makes requests to the API using HTTP methods (GET, POST) and parses the JSON response data.

How Treblle Supports the API-First Approach

Treblle is a powerful tool for teams adopting the API-first approach, offering features that simplify API management from design to deployment.

1. Real-Time Monitoring & Error Tracking: Treblle provides live insights into how your API is performing, including response times, request rates, and errors, helping teams quickly identify and resolve issues.

2. API Documentation: One of the key challenges in the API-first approach is maintaining up-to-date documentation. Treblle automatically generates documentation based on your API design, ensuring that it’s always aligned with the latest version. This makes onboarding new developers faster and ensures consistency across teams.

3. Collaboration Tools: With Treblle, both backend and frontend teams can work in parallel. Its API testing tools allow developers to mock API requests and responses, facilitating a smooth development process without waiting for complete backend implementation. This promotes parallel development, which is central to API-first methodologies.

4. Security and Compliance: APIs often deal with sensitive data, and Treblle helps ensure that your APIs comply with regulatory standards (such as GDPR) by offering insights into potential vulnerabilities and security gaps in your API traffic.

5. Version Control and Analytics: Managing changes to an API is critical in an API-first environment. Treblle supports version control, allowing teams to manage updates without disrupting users. Its analytics feature also provides usage metrics, helping teams optimize their APIs based on real-world data.

6. Developer Experience: By providing a clear interface with comprehensive tools, Treblle enhances the developer experience, ensuring that APIs are easy to integrate, use, and maintain. Its user-friendly dashboard simplifies the monitoring and debugging process, making it easier for developers to focus on building and scaling.

Navigating the tough paths to becoming API-first

Adopting the API first approach is the natural choice for organizations who want to make APIs the center of all their strategies. 

There are several paths such as design-led, code-led, prototype-led, proxy-led, and collection-led that you can follow to become API first. Remember, implementing the API first approach has a large upfront cost, but also results in larger benefits – technical flexibility, Improved developer experience, system interoperability, and the ability to innovate and release products quickly. 

If you’re an organization that has yet to use APIs in a tactical sense, then API-first is not the right approach for you. For organizations already adopting the design-led approach to APIs, you're on your path to becoming API-first!