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When two different software applications want to join forces by sharing information, it’s not always a perfect union. Different database structures, programming languages, and network protocols tend to complicate the process. So how can two applications exchange data in a way that they both understand?In the modern era of cloud computing and service-oriented architectures, web service APIs have emerged as the solution to that problem. Over the years, several API (application programming interface) protocols and standards have come along with their own take on enabling communication between multiple endpoints. When reading about the various  API technologies, you’ve probably come across two terms, OData and REST, and wondered, “what’s the difference?” It turns out that OData vs. REST are two closely related concepts. While they aren’t the same thing, they share a common approach to getting things done. You can think of OData as a set of principles for building RESTful APIs that focuses on your business logic rather than the technical side of building APIs.

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What Is REST?

REST (REpresentational State Transfer) is an API architectural style that defines how to send messages between two different apps using the HTTP protocol. Originally developed by Roy Fielding as a response to what some developers saw as the limitations of SOAP APIs (primarily SOAP’s strict reliance on XML), REST APIs can send messages in a variety of formats and languages, like CSV (comma-separated value) files and JSON. With the relative ease of use and flexibility compared to developing SOAP APIs, REST has grown to become the most popular architecture for exchanging information on the web.

The REST standard outlines six different principles or architectural constraints for web services:

  • Uniform interface: All REST system components must follow the same rules and interface to communicate with each other. Each resource is uniquely identified by a URI (uniform resource identifier).
  • Client-server: REST separates servers from clients. The role of servers is to store information, while the role of clients is to retrieve information from the servers. This separation allows both sides to be independent and more scalable.
  • Stateless: All requests made using REST are stateless. Each request contains all of the information necessary for the server to execute the request. The server is not required to remember the state of previous transactions by storing parameters after the request is complete. For example, if a client requests access to a restricted resource, the client must send its authentication token to the server with each request it makes.
  • Cacheable: Both clients and servers in REST can cache resources, helping to reduce traffic and improve performance.
  • Layered system: REST supports and encourages a layered system architecture. Each client can only communicate with a single server in the system, while other servers perform functions such as authentication and data storage. The client cannot tell whether it is communicating with an end system or an intermediary.
  • Code on demand: REST requests can return logic or executable code if needed. This optional feature distinguishes REST APIs from SOAP APIs, which can only pass XML data.
  • An API that adheres to the above principles is known as a REST (or RESTful) API. 

What Is OData?

According to the website, OData or Open Data Protocol “defines the best practice for building and consuming RESTful APIs. OData helps you focus on your business logic while building RESTful APIs without having to worry about the approaches to define request and response headers, status codes, HTTP methods, URL conventions, media types, payload formats and query options etc.” 

REST is the most important component technology of OData. All OData users should adhere to the six REST principles unless there is a good reason not to do so. OData differs from REST and gains its focus on business logic in its feature set. Whereas REST is an architectural style solely concerned with data transfer via web service APIs, OData builds upon that architecture with a set of metadata that can be easily integrated into most programming and scripting languages.

In an example found in the OData documentation, an OData query is built to find out the two most recent employees who have registered for a business trip, with costs of $3,000 or more for the trip. The example gives code samples for inserting the query into languages like JavaScript, C++, and C#. By integrating metadata into the languages that developers use, OData shifts focus away from typical REST constructs like HTTP headers and moves it toward the application’s internal logic.  

The OData standard also defines the data model used to transfer data in response to a REST request. OData supports two different protocols for transferring data: the XML-based Atom format (for publishing and editing web resources) and JSON (for storing data in a human-readable manner).

Finally, OData includes guidance for how to perform actions such as tracking changes, defining reusable procedures, and sending multiple (batch) REST requests.

The History of OData

First created at Microsoft, OData was standardized by the nonprofit consortium OASIS (Organization for the Advancement of Structured Information Standards). As an OASIS standard, several large technology companies such as SAP and Salesforce have used the OData specification in their internal IT environments—and as a way for their customers to integrate business data.

Now up to version 4.0.1, OData has gained a wide variety of improvements and new features over the years. Some of the changes in version 4 include: 

  • Improvements to the data model, supporting many new metadata constructs.
  • Simplified URL patterns, specifically with regard to key-value pairs.
  • New schema and query options with improved filtering features.
  • New features that make it easier to work JSON data.

OData vs. REST: What’s the Difference?

A quick summary of the difference between OData vs. REST is as follows:

  • REST is an architectural style for exchanging information via the HTTP protocol. The REST standard defines six principles (one optional) that must be adhered to by any REST API.
  • OData builds on top of the REST framework to define best practices for building REST APIs—including the HTTP message format, how to query the API, and more. Although OData encourages users to follow REST principles at all times, this requirement can be relaxed if there is a compelling reason. In addition, OData specifies that data should be transferred in Atom or JSON format.

Developers choose to use OData because of these benefits:

  • OData interacts with data using REST principles with a host of additional features.
  • OData services offer a uniform way to share data.
  • Broad integration across a wide range of products is easily accomplished.
  • As with SOAP and REST, using the HTTP protocol simplifies web integrations.

In the end, deciding whether to use a standard REST API or OData will come down to your business needs and what you need to do with the data.

REST might be the better choice for simple data retrieval due to the speed and simplicity of development. If your needs are more complex, with specific business requirements, OData is likely to be a better fit due to how it naturally fits into programming logic. OData is also an extensible open standard, which allows developers to tap into the open-source community for code that meets business needs.

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REST vs. OData: Get Started With DreamFactory

Whether you’re using OData or not, building your own REST API is time-consuming and technically complex. This is why companies look for an API management platform to streamline API development and management. The DreamFactory internet Platform as a Service (iPaaS) can automatically generate and manage REST APIs, helping you eliminate bottlenecks and modernize your legacy IT applications.

Ready to see how DreamFactory can digitally transform your organization? Get in touch with our team today for a chat about your business needs and objectives, or start your free 14-day DreamFactory trial.

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