APIs are useful for many tasks like integrating social media with your CRM and gathering customer marketing metrics. However, it’s important to know how they work before using them.
RESTful APIs follow six requirements that simplify client-server communication. This allows developers to scale their code independently of the server.
Authentication
The security of RESTful APIs depends on a number of factors, including authentication and authorization. Authentication involves verifying that a person is who they say they are, while authorization checks whether that person has permission to manipulate a particular resource. The goal of a security strategy for RESTful APIs should be to combine these functions and protect the entire application.
A RESTful API is a web service that uses HTTP to exchange data with other programs. For example, if you use PayPal on your e-commerce website to process payments, you are using a RESTful API. A RESTful API can also be used to integrate a database with other software programs, such as your customer relationship management (CRM) program.
One of the main advantages of a RESTful API is that it allows the server to provide information that can be cached by the client. This can improve performance and scalability of the system. The server side of a RESTful API can be configured to respond to requests in different ways, depending on the needs of the system.
A RESTful API should have a uniform interface, be stateless, expose directory structure-like URIs, and transfer data in the form of XML or JSON. It should also use standard HTTP methods to interact with resources, such as GET to retrieve representations, POST to create resources, and DELETE to delete them.
Access control
While REST APIs are the preferred way to develop websites and apps, they can be tricky to manage without access control. Public APIs with no access control run the risk of being farmed by malicious clients and can lead to large bills for bandwidth and compute cycles. This can be avoided by using API keys to limit the number of requests and allowing the use of only a limited set of resources. This approach also enables organisations to monetize their APIs.
The client-server model that underlies REST allows developers to separate the user domain from the data storage domain. This simplifies the development of new applications and web sites. It also helps to manage the load on the server. For example, the server can handle reading and writing data (as opposed to handling UI and request-gathering), while the client handles user interfaces.
REST uses HTTP methods to define interaction with the data, including GET for retrieving representations, PUT for creating or updating resources and DELETE for deleting them. These methods are used to communicate with the server, and can also include headers and parameters that help filter results or bind data. For instance, a DELETE operation can be restricted to the current user by imposing a Never access type. This takes precedence over other access types, such as Always or Read:Never.
Caching
Caching is a powerful tool that improves the performance of REST APIs by reducing their response times. It works by storing the API response in a cache, so that the next time a client requests it, the server doesn’t have to send it again. Caching also reduces bandwidth usage and server load, which is especially important during peak hours.
When caching is implemented correctly, it can improve the performance of an API without compromising its integrity or security. However, it is important to note that it may not work on all clients, so you need to test your API with different versions of the client to ensure that it will work properly.
One of the most effective ways to implement caching with RESTful APIs is to use ETags in the responses. These tags let the client know that a cached copy of the resource is valid. The server can use the Last-Modified or If-Modified-Since headers to revalidate the cached data, and then return the latest version of the resource to the client.
Another way to improve the performance of a RESTful API is to use a reverse proxy, such as Varnish, to cache the API responses. This will allow the API gateway to serve the cached responses to clients, which can greatly improve performance and reduce server load.
Security
The REST architectural style enables developers to build secure APIs by following several security principles. For example, they can use HTTP to transmit data and protect it with SSL authentication. They can also implement a policy of least privilege, which means that each resource or data record has only the minimum set of permissions required to perform its function.
Another aspect of RESTful architecture is that communications between servers and clients are stateless, meaning they do not rely on the context or history of previous transfers. This design ensures that each message contains all the information necessary for a given action. It also allows the server to cache responses and reduce the workload.
API requests often contain sensitive information like credentials, API keys, and session tokens. If these details are included directly in the URL, they can be easily leaked if cybercriminals obtain web server logs. In addition, these parameters can be subject to attack if they are sent over unencrypted connections.
To prevent these types of attacks, an organization should employ continuous API discovery capabilities. These tools will help identify shadow APIs that have been implemented outside of formal processes or old, forgotten zombie APIs that haven’t been decommissioned. Then, they can use conformance scanning to detect potential vulnerabilities. Once these vulnerabilities have been identified, they can be remedied using REST API best practices.