What Is a REST API? Definition & Use Cases

The widespread adoption makes REST APIs ideal for connecting different systems and web services, both within and between organizations. REST APIs enable applications to exchange data and functionality regardless of their underlying technologies or programming languages.

Another convenience is that REST APIs are generally well documented. Tools like Swagger/OpenAPI help create interactive documentation that makes REST APIs easier to understand and use.

What is a REST API?

A REST API or RESTful API is an Application Programming Interface developed to adhere to the architectural style of REST (Representational State Transfer). REST architectural style describes the design for creating networked applications. It's a communication standard that applications use when “talking” with each other over the internet.

Here are the components that make REST APIs work:

• REST is a set of rules for how communication should happen.

• REST uses simple HTTP requests – the same protocol any web browser uses to load websites.

• Each piece of information is treated as a resource with its own unique address (URL).

• Applications can perform basic actions on these resources: get information, post new information, update existing information, or delete it.

• Data is typically exchanged in simple formats like JSON or XML that both humans and computers can read.

REST APIs are popular because they're relatively simple, scalable, and work well with the existing structure of the web.

How do REST APIs work?

REST APIs typically use standard HTTP methods, the most common being:

• GET to retrieve data

• POST to create new data

• PUT/PATCH to update existing data

• DELETE to remove data

When you use an app that needs to access data from a server (like checking the weather, ordering food, or viewing social media), you're likely using a REST API behind the scenes.

A typical REST API interaction flow:

1. The client sends an HTTP request to a specific endpoint (URL)

2. The server processes the request and returns an HTTP response with a status code

3. The response typically includes data in a format like JSON

What are REST APIs used for?

It’s very common to encounter REST APIs when using day-to-day web services.

Web & mobile applications: Connecting frontends to backends, enabling user authentication and data operations.

Microservices architecture: Facilitating communication between independent service components.

Third-party integrations: Incorporating external web services like payment gateways, social media platforms, and web data collection services.

Cloud services management: Programmatically controlling cloud resources (AWS, Azure, etc.).

IoT device management: Enabling remote monitoring and control of connected devices.

Data retrieval & manipulation: Standardized methods for CRUD operations (Create, Read, Update, Delete).

Public data access: Retrieving information from services like weather, stocks, maps.

Single sign-on authentication: Managing centralized authentication across multiple systems.

AI integration: Accessing pre-trained models and analysis services.

Benefits of using REST APIs

The usage benefits described by the core principles of REST APIs include:

Statelessness: Requests must contain all needed information. The server stores no client context between requests.

Client-server architecture: The client and server are separate entities that communicate over HTTP.

Uniform interface: Resources identified by URLs and manipulated through standard HTTP methods with self-descriptive messages.

Layered system: A client cannot tell whether it's connected directly to the end server or an intermediary.

Resource representation: Resources can be represented in different formats (JSON, XML, HTML, etc.). The client and server agree on the format using content negotiation.

Cacheability: REST allows responses to be marked as cacheable or non-cacheable, which can significantly improve performance by reducing unnecessary server calls.

Scalability: The stateless nature of REST APIs makes them highly scalable, as servers don't need to maintain client state between requests.

Platform and language independence: REST APIs can be used with virtually any programming language (most commonly, cURL, Python) that can make HTTP requests and parse the responses.

Best practices of REST APIs

REST APIs are a cornerstone of web development. Here are the best practices for designing and using them effectively.

Status codes: Use standard HTTP status codes meaningfully:

• 2xx: Success

• 3xx: Redirection

• 4xx: Client errors 

• 5xx: Server errors

Resource-oriented URLs: Use plural nouns for collections (/Users), not verbs (/getUsers), and show relationships hierarchically (/Users/123/orders).

Versioning: Include the API version in the URL or header (/api/v1/resources).

Pagination: Implement for large datasets with limit/offset or cursor-based approaches.

Implementation details: Include API versioning, support pagination for large datasets, and enable filtering/sorting via query parameters.

HATEOAS (Hypertext As The Engine Of Application State): Include links to related resources to improve web API navigation.

Security: Use HTTPS only, implement proper authentication (OAuth/JWT/API keys), add rate limiting, validate inputs, and avoid exposing sensitive data in URLs.

Documentation: Provide comprehensive docs with examples using standard formats like OpenAPI/Swagger, including expected request/response formats.

Examples of how to use REST APIs

You should seek the following logic when using REST APIs.

1. Find documentation: Start by reading the API documentation to understand available endpoints, required parameters, and authentication methods.

2. Authentication: Most APIs require authentication.

• API keys: Included in headers or query parameters

• OAuth: More complex flow for secure authorization

• Basic Auth: Username/password encoded in headers

3. Send requests: Use an HTTP client to send requests.

4. Handle responses: APIs return status codes and data.

5. Process results: Parse and process the results.

Web Scraper API

Oxylabs Web Scraper API is a REST API that facilitates the retrieval of public data from websites. The API addresses every aspect, from crawling URLs and bypassing anti-scraping measures to precise data parsing and delivery to your preferred cloud storage.

Web Scraper API integrates into your system to close the gap between your final objective and the vast informational resources lurking in publicly available web data.

For instance, you can feed data from Web Scraper API directly to LLMs as it transforms raw HTML into formats that Claude, GPT, and other large language models can immediately understand.

Data retrieval

To retrieve data, you have to send a scraping request. Here are the steps you would typically have to describe:

1. Import the requests library to handle HTTP requests.

2. Import the pprint module for nicely formatted output.

3. Define the payload containing the scraping parameters, including the target website.

4. Send a POST request to the Web Scraper API endpoint using your Oxylabs credentials.

5. Print the JSON response from the API.

NOTE: The universal source allows scraping from any type of website, but you can also use dedicated sources (like ecommerce, google, etc.) depending on your target.

import requests
from pprint import pprint


# Structure payload.
payload = {
    'source': 'universal',
    'url': 'https://YourTarget.com',
}

# Get response.
response = requests.request(
    'POST', 
    'https://realtime.oxylabs.io/v1/queries',
    auth=('USERNAME', 'PASSWORD'),
    json=payload,
)

# Instead of response with job status and results url, this will return the
# JSON response with the result.
pprint(response.json())

When comparing programmatic web scraping vs. API, REST APIs save lots of time and resources on development effort while offering high scalability at the cost of reduced flexibility to tailor some of the individual steps.