OAuth vs. OAuth2: Key Differences and When to Use Each

5 min read Michael Carroll on Nov 14, 2023

With 61% of data breaches involving stolen credentials, businesses are actively adopting techniques to counter malicious online attacks and protect customer information. 

OAuth, or Open Authentication, is an identity authentication and authorization protocol that permits application interactions without a password. It has many forms, with the most popular being OAuth1 and OAuth2. 

In this article, we'll explore both authentication protocols to identify which is better for your application. 

What is OAuth1?

OAuth1 (or OAuth) is an authorization protocol that lets users approve application interactions without sharing their passwords. Instead, OAuth verifies user identity by assigning authorization tokens which the user has to approve to allow access. Users can decide the extent of an application's access. For example, some applications may have full access to requested apps while others only get read-only access. 

How does OAuth1 work?

OAuth1 has three main components: user, consumer, and service provider. Let’s illustrate this using a simple example where Mike (user) wants Instagram (consumer) to share his posts on his Twitter (currently X) (service provider) stream. 

  1. First, Mike will let Instagram know that he wants the application to post directly to his Twitter stream. 

  2. Next, Instagram will reach out to Twitter for a request token that Mike can use to approve Instagram’s access request. 

  3. Once Instagram receives the request token, it redirects Mike to Twitter with the request token, so he can authorize access and approve what actions Instagram can make on his behalf. 

  4. Finally, Instagram will reach out to Twitter to convert its request token to an access token (and a unique identifier called a "secret"), giving Instagram authority to post on Mike’s behalf. 

NOTE: The service provider uses the "secret" to verify requests are from the actual consumer and blocks any requests it can't verify. 

Benefits of OAuth1

OAuth1 has grown in popularity since its inception in 2006 because it considerably simplifies the third-party integration process. It continues to be used today because it offers so much more:

1. Security and access control

OAuth1 lets you securely share data between applications without worrying about usernames and passwords leaking. Moreover, users authorize how much access applications have and can revoke that access at any time.

2. Flexibility and compatibility 

OAuth1 is a widely adopted security protocol, making it compatible with most applications in the market today. Also, because it's an open-sourced protocol, developers can create a custom authorization process to suit their needs.   

3. Data protection

Since OAuth1 doesn’t use passwords or usernames, hackers will find it harder to steal login credentials or personal info. Users can rest assured their data remains safe while accessing third-party applications.

Drawbacks of OAuth1

Using OAuth1 creates some challenges during development and implementation.

1. Complex signature mechanism 

OAuth1 uses a signature mechanism that the consumer and service provider must use. Generating and verifying these signatures is expensive and prone to error. 

2. Token management

OAuth’s token system (request tokens, access tokens) and their associated secrets can create storage and management complexities. Moreover, debugging and diagnosing signature or cryptographic errors in tokens can be challenging.

3. Negative user experience

Multiple redirects and steps in the authorization process can create a confusing user experience—leading to drop-offs and negative feedback online.

To mitigate these limitations, developers created the OAuth2 framework in 2012, which offered a more streamlined and flexible approach to authorization and authentication. 

OAuth2: The successor to OAuth1

OAuth2 is a more modern and widely adopted protocol for authentication and authorization. It completely redesigns OAuth1 to make it easier for developers to implement authorization processes. 

The main difference between the two is that OAuth2 breaks down the service provider's role into resource server and authorization server to reduce the workload at the provider's end. It also refers to the consumer as the "client" and the user as the "resource owner."

OAuth2 follows a six-step process to authorize access. We’ll use the same example where Mike (resource owner) wants to allow Instagram (client) to post on his Twitter (resource server).

  1. Instagram will request Twitter access via the authorization server. 

  2. The authorization server sends Mike a prompt to verify the authorization grant. 

  3. Once verified, the authorization grant is returned to Instagram. 

  4. Using the authorization grant, Instagram requests the authorization server for an access token to use Twitter.

  5. The authorization server validates the request and sends an access token to Instagram. 

  6. Now, Instagram can post on Mike’s behalf without sharing any personal credentials.

Differences between OAuth and OAuth 2.0 

OAuth 2.0 was introduced to address OAuth’s drawbacks, so you can likely guess where most of the differences between the two arise.

Non-browser application support 

OAuth1 was designed specifically for web applications and doesn’t work well with non-browser clients. OAuth 2.0 circumvents this by introducing multiple authorization paths. This way, you can choose the best path for desktop, mobile, living room applications, etc.

Simpler signing mechanism

OAuth1 requires that signatures generated at the server and endpoint be exact matches. OAuth2, on the other hand, removes this requirement by using Transport Layer Security (TLS) or Secure Sockets Layer (SSL) to protect messages during transit. 

Better security

OAuth1 lets you store tokens for a year or more, while OAuth2 offers access tokens with a short expiration date. These refresh tokens offer better security and reduce the chances of phishing. New tokens can be produced without reauthorizing. 

When to use OAuth 2.0

Aside from third-party app authorization and authentication, OAuth 2.0 supports use cases such as:


Developers can set up an OAuth 2.0 protocol that can allow one service to access another in the microservices architecture.

API gateways

API gateways themselves act as the authorization server and issue access tokens to clients. When a request is made, the API checks the client’s token to approve access without sharing credentials.

Smart devices 

OAuth 2.0 offers multiple authorization pathways specifically for devices with limited input capabilities like smart TVs, refrigerators, air conditioners, etc.

OAuth1 vs. OAuth2: Which one should you choose?

Choosing between OAuth1 and OAuth2 all comes down to the use case. 

OAuth1 doesn't offer SSL/TLS-based security. Instead, it uses digital signatures to authenticate messages. If the message is incorrectly signed or the signature doesn't match, the entire transaction will be canceled. Using OAuth1 makes sense for applications where security is extremely important. This is why Mastercard still uses OAuth1 for server-to-server authentication. 

However, client-side implementation is more complex in OAuth1. So for cases where ease of use is paramount, developers opt for OAuth2. It uses TLS and tokens, which are easier to integrate and troubleshoot. This is why Google switched completely to OAuth2 in 2012 to make linking all their applications easier.

Simplifying the authorization process

OAuth1 and its successor OAuth2 represent two distinct authorization and authentication approaches. 

OAuth1 enhanced security and user control. But it also presented certain complexities in terms of signature mechanisms and token management. Meanwhile, OAuth 2.0 offered a more adaptable authorization protocol that could be used with a broad range of applications, including non-browser clients and smart devices. 

Despite these differences, OAuth1 still holds its own, particularly in legacy systems. Your choice of authorization protocols should be defined by your business’s unique needs and requirements.

PubNub offers a secure platform where developers can build real-time chat and messaging applications. Developers can ensure both the user data and application are protected from external attacks by integrating OAuth along with PubNub’s other security features. 

Get in touch with us to learn more about our offerings or sign up for a free trial to explore how PubNub enables secure real-time interactions.