How can you design a RESTful API for maximum extensibility?

Too many people are creating so called REST APIs where they include the verb like getCustomer, createCustomer, which means they haven't made the intellectual leap from things like SOAP to REST and that the method or verb in REST is done as part of the semantic web; i.e. create, get, update, find, patch are part of the HTTP protocol; so the HTTP method against the resource is what differentiates between the different methods. This is why you should not put the verb in the name. Also, I always wondered why a lot of REST APis don't evolve much beyond version 1.0 or 1.1 and that is because if you get this right, you shouldn't have to change the API very often; i.e. highly cohesive, highly purposed APIs that perform a limited operation.

-Identify entities as resources, using standard HTTP methods -Use version numbers to support future updates without disrupting existing users. -Design resource representations with optional fields for adaptability. -Implement filtering and pagination for managing large data sets. -Provide consistent error messages for effective debugging. -Use standard codes to clearly indicate request outcomes. -Create concise, comprehensive documentation with examples. -Develop a robust test suite to ensure API reliability Security Measures. -Implement strong authentication and authorization mechanisms. -Include a user feedback system for input and improvements.

Maximum extensibility will be obtained by incorporating API version numbers and backwards compatibility if newer versions have small to small-medium changes. Sometimes a newer API version can contain default values to facilitate the backward compatibility. Of course, as already mentioned, naming conventions are important for usability purposes.

Imagine your RESTful API as a recipe for a yummy pizza. You want to make sure that each ingredient (like tomatoes, cheese, and dough) can be easily added or changed without messing up the whole pizza. So, designing a good API is like creating a pizza recipe that lets you customize the toppings easily, ensuring you can always make your favorite pizza, whether you want to add new toppings or switch them around!

Consider the following principles: 1. **Modularity and Decoupling:** 2. **Resource Naming and URIs:** 3. **Versioning:** 4. **HTTP Methods:** 5. **Request and Response Formats:** 6. **Documentation:** 7. **Authentication and Authorization:** 8. **Error Handling:** 9. **Testing and Validation:** 10. **Rate Limiting:** By adhering to these principles, your RESTful API can be designed with extensibility in mind, providing a solid foundation for future changes and additions while maintaining a clean and predictable interface for developers.

Break down functionality into modular components with well-defined responsibilities and interfaces. Implement versioning to ensures backward compatibility. Provide documentation that clearly explains the API endpoints, parameters, and expected responses to aid developers in understanding and extending the API. Allow developers to customize or extend certain endpoints based on their requirements through query parameters, request headers etc. Implement a plugin system that enables developers to add or extend features without modifying the core API. Use authentication and authorization mechanism for control over who can extend or modify. Design the API to be scalable with caching and distributed systems to handle additional load.

To apply the HATEOAS (Hypermedia as the Engine of Application State) principle in your RESTful API, include hypermedia links within resource representations, use standardized link relations, dynamically generate links based on the current state, provide links to actions on resources, ensure clear documentation, establish consistent linking patterns, consider versioning, design clients to be responsive to changes, thoroughly test and validate implementations, and promote API discoverability. Following HATEOAS enhances API flexibility, discoverability, and adaptability for developers.

Good point. This will require one to take a holistic view and understand the relationships between various transactions/processes instead focusing on one transaction/process. Getting a design review done (different than the coder) before coding will be a good idea.

Include hypermedia links in responses to guide clients through the API. This allows for dynamic discovery of resources and actions, reducing dependency on hardcoded URLs.

A Restful API frontend should be modular, and each call it makes should be explicit. The backend (the main part of the Restful API) should be designed with SoC (Separation of Concern) and Abstraction. There should be a parent (a central play for all the calls) and there should be handlers...This will keep your codebase clean and abstract. Implementing this covers the OCP (open-close principle) which allows the central part of your code to exist and remain functional (and unmodified for the most part - you avoid breaking your application) while you extend it.

Use the time tested open/closed principle. Design your API so that it can be easily extended, but closed for any breaking changes, and include the ability for the consumer to request a specific version for when a breaking change cannot be avoided. We put the version directly in the path as this makes it very explicit. But you can also use various header mechanisms, just be careful to provide a good default behavior if header isn’t specified.

Ability to monitor subscribers to old versions is very useful. This can help in deciding deprecation dates for unused / rarely used API versions.

One thing which I have found helpful that if you Implement versioning from the beginning to support future changes without breaking existing clients. This can be done through URL versioning or using headers.

I think keeping good handle on API versioning always pays off. Once the system will grow bigger and more changes will come. it will help to keep the backward compatibility. In APIs using URL based versioning serves the good purpose.

Publish coding standards with these guidelines. Establish sound QA. Make sure code review and testing are effective to ensure these are in place.

Authentication and Authorisation strategy is the key pillar of successful and secure application. One must Design a robust authentication and authorization system that supports various mechanisms. This ensures security while providing flexibility for future integrations.

Authentication is indeed about verifying the identity of the client accessing the API. It answers the question, “Who is the user?” This could be done through various methods like username/password, tokens, certificates, or even biometric data. Authorization, on the other hand, is about granting access rights to authenticated users. It answers the question, “What is the user allowed to do?” This often involves checking the user’s roles or permissions against the access control rules defined for the resources or actions.

One cannot stress enough on the need of securing the Restful API. Make sure that this is incorporated early. Do not postpone it for later as it can lead to unsecured API used during early development to get migrated to production. Make sure that sound QA is in place and security testing/certification process is in place to catch oversights and adding risk once it gets into production.

Cela est en effet indispensable et est un pilier de l’APIsation et transformation digitale. L’usage d’api gateway et la ma?trise des canaux de diffusion est cruciale notamment en terme de sécurité (api public vs api privée).

Lack of (standardized) authentication and authorization will kill the reusability of APIs (as they become a risk). This will lead to more versions of similar APIs instead of extending existing APIs. It's a must to protect wisely!

From API testing and documentation perspective. I think nothing works better that TDD ( Test Driven Development ) approach and having a swagger. Where developer has to write the possible test scenario using the test framework first and then code the API against those test cases. Document is good but often I found that they become stale as APIs are getting upgraded while keep the tab on document may not be possible. However, having a document which details out the API is always good

Agree. This is common sense. Documentation and Testing should be part of any software development process, not specific to Restful API.

Create comprehensive documentation with clear examples and explanations. A well-documented API enables developers to understand and extend it more effectively. Establish a thorough testing process and integrate continuous integration practices. This helps catch issues early, ensuring a smoother process when extending or modifying the API.

On of the most important thing to do when you design a rest API is to describe and provide documentation for API routes. Consumers need to be aware and also need also to understand what this route does, also you need to provide an example so they can test your API. Swagger is a very powerful for APIs design and testing. Postman is also a very good tool that you can use for APIs, for both manual and automated testing.

Apart from this use OpenAPI Specification, is primarily employed for API design, documentation, and testing. This will help greatly for the user where they have every thing in a single tool there is no separate need for a documentation . Swagger is a good tool

Here are some additional points to consider. Telemetry: Identify and implement telemetry requirements for API. Monitor API Dependencies: Monitor internal and/or external APIs may be dependent on the APIs. Metrics: Identify which metrics are most important for your API's performance and focus on those metrics. Build for live site: Build for live site support and focus on measuring and reducing Mean Time To Resolution (MTTR). Definition of Success: Identify, Monitor and Alert functional and non-functional definition of success for the API

We design RESTful systems, which may utilize a REST API or any other style, channel, or protocol for exposure. This article appears to prioritize embellishments rather than delving into the core principles that distinguish a truly RESTful system. It's important to underscore that the foundation of a RESTful system lies in the design of the domain model, which dictates whether the entire system aligns with REST principles or not.

Using OpenAPI specifications will help immensely in making the API extendible. One of the most useful features of the specifications is the schema section. To make the REST API extendible, I would recommend to separate the schema that describes the request response data types in its own schema section.

a. Modular Design: Embrace a modular design approach that allows the API to be divided into smaller, independent modules or microservices. Each module can have its own set of functionalities and data, making it easier to extend and enhance specific features without affecting the entire API. This modular structure promotes scalability and adaptability. Example: In our project, we implemented a modular architecture where user-related functionalities, such as authentication and profile management, were separated from product-related functionalities. This allowed us to independently scale and update these modules as needed.

few other considerations 1. Rate limiting 2. discoverability 3. OpenAPI standards 4. circuit breaker and retry options 5. API gateway implementation