If you’re looking to quickly and easily build out the functionality of your website, or if you’re new to development, REST APIs are a great place to start. By allowing different applications and application components to interact with each other, APIs save developers the trouble of writing custom code from scratch. This makes them an almost indispensable tool for programming.
REST APIs are an especially popular choice, as they are easy to use and develop, so knowing the basics of REST APIs is key to both simplifying development and adding third-party functionality. This post will provide you with the basics of REST APIs, explaining what they are and how they work, their advantages and use cases, the challenges of using them, and how serverless computing can be used to easily create REST APIs that are fast, efficient, and reliable.
What Are REST APIs?
Conceptually, you can think of APIs as a way of communicating with a service. It’s a special communication channel that allows you to make a request to the server which in turn returns an encoded response, typically in JSON format.
Each request is treated independently or stateless, meaning it has no memory of the last request you (the client) made to the service (the server). It’s something akin to communicating with a person who has instant amnesia after the response has been fulfilled.
REST, which stands for Representational State Transfer, is a set of rules for building a specific type of API that is used in web applications. As explained in an article on GeeksforGeeks, REST “allows requesting systems to access and manipulate web resources by using a uniform and predefined set of rules.” Using these predetermined rules to structure APIs makes them easier to build and easier to understand, increasing their adoption by third-party developers.
To qualify as a REST API, it must adhere to the following architectural constraints:
- client-server architecture: requests are initiated by the client and returned by the server, simplifying communication and keeping clients and servers separate and independent.
- statelessness: each interaction is treated as a new, independent task; no information is stored between tasks.
- cacheability: responses include information about whether or not the information can be cached and how long it can be cached for.
- layered system: application architecture is composed of multiple layers so that intermediary servers can perform tasks, such as load balancing and security, without affecting client-server interactions.
- uniform interface: all requests and responses follow a common protocol for formatting messages.
In addition, many REST APIs also enable code-on-demand, where clients can call the API to get a UI widget rendering code.
How Do REST APIs Work?
As a blog post on Hubspot explains, “REST APIs work by fielding requests for a resource and returning all relevant information about the resource, translated into a format that clients can easily interpret (this format is determined by the API receiving requests).” Requests are made up of four elements:
- The endpoint: the URL you are requesting for
- The method: the HTTP method used to make the request (such as GET, POST, DELETE, PUT, or PATCH)
- The headers: which hold additional information about the response or request
- The data (or body): the information you want to send to the server (only used with POST, PUT, PATCH, and DELETE methods)
After the client makes a request, the server responds to the request and returns an HTTP status code providing the request’s status. Status codes are divided into five categories:
- 100s - provides information and directs the client to wait for a final response
- 200s - the request was successful
- 300s - the request requires additional action by the client, such as URL redirection
- 400s - the request failed due to a client-side error
- 500s - the request failed due to a server-side error
Individual response numbers provide more information about the request status, such as 401 Not Authorized, which signals that authentication has failed. This information helps API users to understand why their code isn’t behaving as expected and quickly fix the problem.
Advantages and Use Cases
REST APIs are popular with developers, as they provide several key advantages. As noted in a blog post by Smashing Magazine a resource used by many developers and designers, REST APIs are easy to develop: “Being fully resource-oriented when working with a REST API, you no longer need to know, or care, what it takes to retrieve a given piece of data; nor are you required to know anything about the implementation of the backend services.” In addition, they are very flexible, enabling many different types of requests and data formats.
With REST APIs you can:
- Integrate different payment methods for e-commerce
- Link your website to your social media
- Add logins using Google or other third-party accounts
- Aggregate flight and hotel availability for easy booking on your travel site
Challenges of REST APIs
No technology is perfect, and REST has its share of challenges. One of the key issues with REST is that today’s applications and websites have many different elements; in order to render a complete application or page, numerous API calls must be made, requiring many round trips to the server. In addition, REST returns far more information than is needed for each request, resulting in very large payloads. Both problems can contribute to higher latency and more resource use, especially if the server is located geographically far away from the client.
Compounding all of this is the fact that servers traditionally handle one request at a time. In the face of a huge traffic spike, the server will respond to requests as they come in, compounding latency gains and potentially leading to timeouts that can leave users thinking a webpage or application is down. To solve this problem, developers need a way of building REST APIs components with low latency, efficient resource use, and the ability to easily scale up to meet increased need.
Using Serverless with REST APIs
One way of addressing the challenges of REST APIs is to use serverless platforms like Azion. Azion combines the power of edge computing with a serverless model. This lets you run business logic at the edge of the network, close to where end users are located, and scale automatically without the need to manage or provision resources. Instead, you pay only when your code runs, resulting in less wasted resources and upfront costs.
Using Azion’s REST API, you can simply and securely integrate your systems with our platform. The API is based on HTTPS requests and uses responses in JSON format, a lightweight data-interchange format that is easy to work with, offers fast parsing, and wide support for browser clients. Azion’s API supports the GET, DELETE, POST, PUT or PATCH HTTP methods, which lets you read, delete, create, replace, and modify resources, and can be used with any of Azion’s products.
In addition, our serverless computing product Edge Functions lets developers build their own REST APIs or create functions to call third-party APIs for easy integration. Edge Functions has many advantages over other serverless computing solutions, such as lower latency and more efficient resource use. By delivering from the edge, rather than centralized data centers, developers can gain lower latency than cloud provider solutions such as AWS Lambda. In addition, AWS Lambda and other cloud solutions use containers to isolate functions, whereas Edge Functions use V8 to secure and isolate functions, resulting in significantly reduced resource use and zero cold starts for faster, more consistent performance.
Edge Functions solves challenges of REST APIs by providing:
- Lower latency
- Guaranteed availability during traffic spikes
- Efficient resource use