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The Principles of API-Driven Development

Idan Gindi
By Idan Gindi
10 min read
API Governance API Observability
The Principles of API-Driven Development

Nowadays, when developers write programs, they don’t start from scratch, since reusable and highly functioning code groups are readily available. API is a piece of code exported by the developer or the company to let other users integrate with our library/service. In general, an API is a software that establishes a connection between two or more software applications.

In this post, we’ll discuss the benefits and challenges of API-driven development and give you some guidelines for using them effectively. We’ll also explore why it’s helpful to view APIs as the basis for an entire architecture structure, rather than just as a tool for building programs. To follow along, you’ll need to know the basics of backend development, in any programming language. 

What Is API-Driven Development?

Let’s get started by talking about what API-driven development, also known as ADD, actually is. With API-driven development, API design is prioritized during the application design process. In other words, API design determines every other part of development.

For API-driven development to work, you need to create an API specification documentation that explains how the API is expected to behave. This contract allows stakeholders, developers, and UI/UX designers to collaborate and agree on the API design—before any coding is done. Then, in test driven development (TDD), specific tests are written to match the API's intended result. Developers utilize these tests to create user interfaces that meet the API contract, while backend developers write the API logic at the same time.

An API-first company implements the API-first method. Prior to this, most companies adopted a code-first strategy, where developers created logic and user interfaces before breaking down complex chunks of code into simple fragments.

API driven dev

Principles of API-Driven Development

There are several guidelines that will help you stick to the API-driven development approach, including: 

Naming Conventions

The naming of endpoints, resources, methods, and messages has a significant impact on the developer's API experience and ability to understand how to use the API and navigate through it.

Here are some tips for naming API resources: 

  • Follow the KISS (Keep it Simple, Stupid) principle. API names should be easily understood by developers of any skill level. They should be simple, intuitive, and consistent.

  • Use American English, as it is the most widely spoken and easily translated language.

  • Using a single term (e.g., /collection) for many ideas is confusing. Instead, utilize names that are more particular, such as /users or /books.

  • Choose names carefully to avoid conflicting with reserved keywords in common programming languages.

  • Don’t use unpronounceable words (e.g., /xwzglh).

  • Avoid file extensions in the URL (e.g., /users.xml). Instead, provide the file type in the `Content-Type` header.

  • Avoid spaces or underscores in the URL. Instead, use a hyphen (e.g., /admin-dashboard or /users-dashboard).

Reusability

Point-to-point integration connects one application to its data source. In contrast, reusability is when a program can be accessed in other programs or interact with multiple assets from a single application—rather than requiring you to duplicate an instance of that functionality every time it is needed in another application.

Any authorized device, application, or location should be able to access the API. This increases efficiency, since mistakes can be traced back to a single source. Reusable apps also use fewer resources(such as databases and hosting) than applications that contain replicated functionalities.

Modularity

This is similar to reusability, but more complicated. A modular API is a piece of code that resides in its own environment and may be utilized by other applications, without needing to be recreated.

It has to deal with the decomposition of complex systems into smaller modules in an object-oriented way such that the complexity of the system is reduced. This way, individual modules could be altered or removed without affecting the entire system. 

Versioning

Sometimes, you need to move back and forth between API updates. To avoid breaking changes, a versioning strategy is employed. Still, because change is unavoidable while building software, it's critical to keep track of versioning to minimize errors and issues.

Changes can occur for a variety of reasons, including bug fixes, improvements, dependency changes, and new features. These modifications are helpful, but not obligatory. In fact, some developers prefer using certain applications before they are updated, which is why the version is so crucial.

versioning

Support for Media Type

Media type is the format in which developers make requests to an API and get response data. JSON, XML, and images are among the most prevalent media formats supported by RFC 6838.

Other commonly used media types include:

  • application/json
  • application/pdf
  • application/xml
  • application/x-www-form-urlencoded
  • image/png
  • multipart/form-data
  • text/html
  • text/plain; charset=utf-8

The media type should be specified in the `Content-Type` or `Accept` header.

Concurrency Control

When allocating software resources(database storage/updates) to users at the same time, modifications made by one client can affect those made by another. Of course, you should try to avoid this.

There are two popular strategies for dealing with this situation:

  • Optimistic concurrency control: Allocate a token for each update transaction to each client. Then give each token validity to perform transactions in a first-come-first-serve order. The client is authorized to perform the update request as long as the token is valid.

  • Pessimistic concurrency control: This enables a client to request an update. The resource is locked as soon as the request is made, so no other client can modify it.

Because you can't simply track activity across several clients while using HTTP, optimistic concurrency control is the best approach.

Appropriate Use of Status Codes

HTTP offers a set of codes that represent certain typical API instances. According to Section 10 of RFC 2616, these codes are divided into five groups, or classes. Here are the code ranges:

When creating APIs, make sure you use the correct status code in the appropriate case, so that other developers can handle the response properly. You can find the modified specification in RFC 7231.

status codes

Security Considerations

You should also think about security when creating APIs, especially those that are open to the public, as they are the most vulnerable to cyberattacks and data breaches.

Here are some examples of common API attacks:

There are several best practices you can follow to secure your APIs against these types of attacks, including:

  • Use OAuth: It’s best to use authentication techniques from more secure or security-focused firms.

  • Validate form inputs: Don't presume frontend developers will validate form inputs. A secondary validation in the API before transferring data to databases isn't a terrible idea.

  • Use rate limitation or throttling: This prevents spamming/overloading on the system and DoS by restricting the amount of times a user can make specific requests.

  • Encrypt traffic with TLS: TLS is critical for sending sensitive data, such as login credentials, bank account information, and health information.

  • Tokenize requests: While making requests, assign tokens to users so that requests with invalid tokens are refused.

Error Handling

In API programming, error handling comes in handy with status codes, tokens, and request headers. The client's response to user requests is determined by how an API handles errors, so there can be a lot of confusion if the incorrect error message is returned.

Consider this scenario: A developer tries to visit a non-existent endpoint and receives a `200` status code, instead of a `404` error. He thinks everything is in order, yet whatever request he made did not complete.

To handle errors, you can use well-known status codes, write explanatory (but short) error messages, and separate general/client errors from server errors.

error handling

Use Cases for API-Driven Development 

Almost any application can use an API-driven development approach. Here are some specific use cases:

  • Headless CMS: A headless CMS is a server-based content management system that is independent of a presentation layer (client). A headless CMS delivers its content via APIs to make it accessible across various platforms.

  • CI/CD pipelines: These are platforms that manage and automate the delivery of new versions of applications.

  • Cloud-friendly applications: Applications that are hosted in the cloud deliver content across various clients or devices.

  • Modular packages: These are application units with standard dimensions of various sizes that fit together to make a functional system.

ci/cd

Benefits of API-Driven Development

Clearly, APIs have a lot to offer. If you’re still not convinced, here are some benefits of API-driven development:

  • Complex applications are broken down into smaller, individual, autonomous services . This way, companies can easily track changes or issues.

  • Features are more accessible and compatible with various platforms.

  • Modular architecture is encouraged, as features will be designed in smaller modules.

  • Since the architecture is modular, shipping becomes easier across distributed environments or platforms.

  • Companies can easily scale applications by implementing features as needed, instead of altering the whole application on every change.

  • Agile or parallel development allows teams to be flexible and work independently.

  • Stakeholders will know exactly what the product will look like before development even starts.

Agile dev

Challenges of API-Driven Development

Despite the benefits mentioned above, there are still some challenges to API-driven development, including: 

  • Consistency: As more APIs are built, it’s difficult to keep them consistent with set standards. This is also challenging when team members change, as developers might not implement everything the same way, causing inconsistencies in the APIs’ design.

  • Compatibility: Over time, more devices become available. However, they might not support APIs that were built a long time ago.

  • Security: Attackers can use loopholes to attack an API or another application that depends on it.

  • Maintenance: Due to new technologies and devices, you have to periodically upgrade your applications so that they function properly with other applications and technologies.

So What’s the Solution?

One effective way to reduce the challenges of API-driven development is observability. As the name implies, observability is the ability to observe and infer what is happening in the internal environment of a system, based on the system’s outputs.

While monitoring an API helps you keep up with its security, performance, and logs, observability is more than that: You create patterns of behaviors and performance and use them to design tests in order to understand what is happening inside the API. You can even send cyberattacks to check system failures or security.

To observe your API properly, follow these steps:

  • Document and define the API in detail.

  • Leverage API gateways like Apache, NGINX, Istio, HAProxy, etc. You can use them to log your API’s behavior and obtain security, health, and performance metrics.

  • Plot graphs of occurrences and visualize data from your API to make its behavior easy to understand.

  • Keep historical reports of your API’s performance, health, and security—either manually or automatically.

NOTE: API observability helps build tractions and metrics for the business side of a system.

Conclusion

API-driven development is still an upcoming idea. We predict that as software technology progresses, more and more organizations and companies will embrace it. As we discussed in this post, there are many benefits to API-driven development—and it’s easy to implement if you understand the topic and follow recommended best practices. 

Seekret provides a ready-made solution for API observability. It helps you explore your APIs with auto-discovery, gain visibility into API behavior, ensure your APIs are on pace with development, and allows you to redefine how you govern them. To see how you can benefit from an API-first development approach, get started today.