OAuth 1.0 vs 2.0 vs 2.1

If you ever need to implement a “Login via Google” feature to your website, chances are you’ve heard about OAuth. Or rather, OAuth 2.0 in particular.

There was a time there was an OAuth 1.0, but things changed, people left the OAuth team, new ideas was put into OAuth, old ideas was removed. Kind of a natural flow for any project. But it OAuth 2.0 shouldn’t maybe be as praised as it is.

OAuth 1.0 to 2.0

OAuth 1.0 is complicated. The specification was difficult to implement, and there were some things left out of the protocol that meant it should only be implemented by someone who had done the full research and understood what OAuth suggests, and make informed decisions when implmenting the missing parts.

This was a major blow with OAuth 1.0. In OAuth 2.0, they simplified the protocol and fleshed it out with a whole suite of samples of how to implement it correctly. After all, most developers are both inadequately studied in security to tackle this, and in most cases a developer is tasked with “just add login via Google”. An opinionated and clear protocol is much more secure when the people who implement it all have regular deadlines.

To simplify, comparing OAuth 1.0 and OAuth 2.0 and roughly be done with the following points:

OAuth 2.1

Development of OAuth has been at a standstill up until recently. OAuth 2.1 is at the horizon and promises to resolve some of the issues with OAuth 2.0. It’s wise to study What OAuth 2.1 brings to the table# before it lands in our [developers] hands, so we can properly prepare for this somewhat big change in how authentication is dealt with over the web.


  • Cambell, R. & Franklin, C.. (Hosts). (2021, January 14). IdentityServer Update with Dominick Baier and Brock Allen (No. 1722) [Audio podcast episode]. In .NET Rocks!. vNext. https://www.dotnetrocks.com/?show=1722