Get in touch

Awesome Image Awesome Image

Software Development January 9, 2023

What is OAuth 2.0, and how does it fit into Spring Boot and Java Microservices?

Writen by Mahipalsinh Rana


In today’s world, Java development is gaining a lot of attention from various businesses. It is all because of the growing popularity of Java. OAuth is an authentication framework that plays a crucial role in Java application development. Users have a secure way to access internet services without having to worry about their login credentials thanks to the OAuth authentication framework. Here is a brief summary of OAuth 2.0’s key features.

OAuth: An Overview

Web applications and websites use OAuth as an authorization framework to gain access to the accounts of other applications and websites. OAuth is essential in that it enables the user to give access without disclosing their login information to the requesting application. This allows users to choose to release the information they would like to share rather than giving a third party complete control of their account.

The fundamental OAuth procedure is frequently used to incorporate third-party functionality that needs access to specific user account data. For instance, a program might utilize OAuth to ask for permission to access your email contacts list so that it might make connection suggestions. The same approach, though, is furthermore employed to offer third-party strong authentication, enabling users to sign in using an account they have with another website.

What is OAuth 2.0?

Now you must be wondering what is Oauth 2.0 exactly? Authorization refers to rules that determine “what user is allowed to do” and what user is not e.g. An employee has the right to access his own details on the portal but the manager can edit or see the details of other employees.

Oauth 2.0

OAuth 2.0 stands for “Open Authorization”, It is designed to allow a website or application to access resources hosted by other web applications on behalf of a user. It doesn’t necessarily require knowing any credentials or their identity.

To define OAuth we can segregate multiple terms that highlight “The OAuth Purpose” in a digital world:

  • Technically, OAuth is an authorization protocol that allows a user to grant limited access from one site to another site without having to expose their credentials.


  • OAuth specifically satisfies the purpose for authorization, not authentication.


  • OAuth is a pathway created for services trying to access each other on behalf of the user.

To define OAuth2.0, we can take one example from the Real world: A valet key 

  • Suppose a car owner wants to park a car in his parking lot by giving instructions to the security guard.
  • One cannot give the master key of a car to a guard which increases the security risk of accessing internal sections such as trunk/panels that holds confidential things in general. To resolve this, the car owner provides an extra key, that has access to ignition only, to be applied only to serve the mentioned purpose.

  • Here, let the Car Owner be a “user”, Car as a “car service” and the Security guard as a “valet service”.

  • Here the protocol via which valet service has limited access to car service is termed as “OAuth” and valet key i.e. limited access key is termed as “Access Token”.

Hire Java developers

What is Spring Boot?

Java programmers can use Spring Boot to create standalone, production-ready spring applications that you can easily execute. Without the requirement for a full setup of Spring config, it is easy to start simply with the bare minimum configurations. You can give Spring boot Java a try to get the best app for your company’s services.

Spring Boot with OAUth2.0

Authentication and permission are essential when creating a web application. Doing it right, however, is not simple. Computer security is a true specialty. A never-ending loop of detecting flaws, exploiting them, and patching them is created as legions of developers battle against an equal number of worldwide hackers. It would be difficult to keep up with everything alone (if not impossible).

Thankfully, there isn’t a necessity. Building a web application using OAuth 2.0 has been made incredibly easy thanks to Spring Security and Spring Boot.  Let’s have a look at some of its key concepts and features.

  • Spring boot works to create microservices
  • Spring Application creates stand-alone spring application
  • Web Application HTTP Embedded (Tomcat, JTTY, or Undertow) No need to deploy a war file.
  • Externalized Configuration
  • Security (It is securely inbuilt with basic authentication on all HTTP endpoints)
  • Application Event and Listener

What is Microservice?

An architecture known as microservice enables developers to freely create and implement services. The lightweight paradigm for supporting business applications is made possible by the fact that each active service has its own process. The demand for microservices has increased in these previous few years and more and more people are availing microservices Java for their business apps.

mechanism to manage credentials, validate the requester’s authorization, and ensure that people are doing as they should when it comes to authentication.

(It is clear that cloud-based application is an easy approach to getting access to various services in one place)

  • As MicroServices are becoming the new norm for enterprise application development, securing those services is also becoming a challenging task. 
  • OAuth 2.0 is a protocol that greatly simplified the work involved in developing and managing security services.
  • Users can’t access the API without a token. The token will be available when the user is given basic authentication details to generate a token for access API.
  • All requests will go through the same API Gateway, yet service-to-service communication is still possible.
  • Every request will check authorization when the request will arrive in service and the service will request an authorization server to verify it is either authenticated or not. 

Securing Microservice with OAuth 2.0

Microservices give us an easy opportunity to scale our application. But when we extend our application, the vulnerability increases. We must devise a strategy for safeguarding our services and preventing unauthorized individuals from using restricted resources. Enabling the user authentication process is one approach to achieving this. We need a mechanism to manage credentials, validate the requester’s authorization, and ensure that people are doing as they should when it comes to authentication.

Securing Microservice with OAuth 2.0

Microservice Architecture With Authorizations

Microservice Architecture With Authorizations

  • The user will get a token if the user’s basic authorization and login credentials are matched.
  • Next, the user sends a request to access data from the service. the API gateway receives the request and verifies it with the authorization server.

  • Every request has one entry point API Gateway.

  • Take care of Routing to the service while verifying for security.

  • Every service has a single database to manipulate data.

Roles in OAuth2.0

  • Resource: A protected resource e.g. Google Drive files or APIs.

  • Resource Owner: A person or thing that has access control rights to resources. Typically, this is the end-user.

  • Client Application: The application that is attempting to get access to the user’s account or a resource on behalf of “Resource Owner” with its permission on Resource Server i.e. APIs. This application could be a website, desktop, or mobile app.
  • Resource Server: The protected and secured resources are hosted by a Web API or web service.
  • Authorization Server:  The main use of the authorization server is to validate the credentials if they are valid then the authorization server generates the access token and passes it to the client application.
We can also make our own authorization server or use third-party authorization servers like Google, Github, etc.

Roles in OAuth2.0

JAVA CTA Banner 2

OAuth2.0 Workflow

OAuth2.0 Workflow

  • User-Resource Owner logs into the Photo printing app to get a photo printed on the mug. The Resource Owner asks the Client to get photos from Resource Server.
  • The client asks the Resource Server to access Photos.
  • Resource Server goes to Resource Owner to allow permission and now Resource Server has information of who is trying to get access and what permissions are required.
  • Resource Owner says Client may be a trusted service and himself have asked Client to get the Resource and allows permission for the printing purpose.
  • Authorization Server provides an auth token to the Client.
  • The client uses the received auth token and contacts the Authorization Server to get an access token.
  • After confirming the auth token from the Client, the Authorization Server sends the access token to the Client. After receiving the access token Client makes an API call to Resource Server to get access to the required resources.
  • Resource Server confirms access token and lets the client access the required resources.

How can OAuth authentication flaws arise?

Because the OAuth standard is intentionally ambiguous and flexible, OAuth authentication flows can occur. Each grant type has a small number of essential elements for basic functionality, but the vast rest of the implementation is entirely optional. This includes numerous setup options that are required to safeguard user data. In other words, there are several opportunities for undesirable behavior to emerge.


The general lack of integrated security features with OAuth is one of its other major drawbacks. The security is largely dependent on the developers choosing the best configuration parameters and adding their own extra security measures on top, including strong input validation. As you can undoubtedly tell, there is a lot to consider, and if you are unfamiliar with OAuth, it is very simple to make mistakes.

Highly sensitive data may also be sent via the browser, based on the grant type, which presents different options for an adversary to intercept it.

Looking for Java Development Services?

Final thoughts

As we can see that in today’s world security has become a major issue in the corporate sector, hence it is necessary to take care of it in all aspects.

OAuth 2.0 is successful and beneficial because of its highly scalable design and the precision of permissions it offers through OAuth Scopes. Hire Java developers at Inexture to get assistance regarding software development. We are one of the top Java development service providers who best take care of client project requirements.

Bringing Software Development Expertise to Every
Corner of the World

United States



United Kingdom




New Zealand










South Africa