UPDATE (2 JULY 2021):  We've extended the deadline to 30 August 2021 for converting Authtoken to OAuth.

UPDATE (30 MARCH 2021):  We've added a set of FAQs to addresses few common doubts that you may have while migrating from Authtoken to OAuth.

Hello everyone, 

The usage of Authtokens to authenticate API calls is being deprecated on 30 August 2021 across Zoho's Finance suite of products, which includes Zoho Books. This change is being done in favour of switching to OAuth 2.0, a more secure and robust protocol. 

This means that any of your existing workflows or custom functions, which rely on Authtokens to communicate with Zoho Books' APIs will no longer function after 30 August 2021, unless you replace Authtokens with OAuth.

Here are some benefits of OAuth, compared to Authtokens: 

• OAuth 2.0 is an industry-standard protocol, which means client applications can communicate with Zoho Books' APIs in a generalised manner, instead of figuring out a custom solution. 
  

• OAuth provides access to Zoho Books' APIs via access and refresh tokens, which do not require you to store your users' Zoho Books credentials on your own client application. 
  

• You can specify scopes for access tokens. This means each access token can provide authentication only to the Zoho Books APIs which you specify. You can also revoke these access tokens at any time, if necessary.
  

• Access tokens expire after a particular amount of time. This limits your data exposure, in case your client application has been breached.