The V1 API has been deprecated, but will continue to function for legacy applications. As of January 1st, 2019, we will only offer technical support for the V2 API.
OAuth 2.0 Authentication
The OAuth 2.0 standard provides your users with a secure way to access Harvest data without providing sensitive information like usernames and passwords.
Registering Your Application
You’ll need to register your application with Harvest (you must be logged in as an administrator on your account to access this page) before using OAuth 2.0 for authorization. After registering, we’ll provide you with credentials that your application can use to communicate with Harvest.
To register your application, please visit: https://YOURACCOUNT.harvestapp.com/oauth2/clients
Note: The OAuth 2.0 Sample App is a great starting point if you’d like to experiment with Harvest’s OAuth 2.0 using your own registered client ID and secret.
Access tokens allow your application to communicate with Harvest on behalf of your users. Each user is granted a token which expires in 18 hours.