Bullhorn customers can obtain OAuth keys for developing applications with the Bullhorn REST API by creating a support ticket via the Bullhorn Resource Center.
The administrator in your company can generate your own key. To generate a key, log into Bullhorn and select Tools > BH Connect > Web Services API. Click Add API Key and create a new key. There is no limit to the number of keys you can generate. It is generally recommended that you generate a key for each new project. That way, you can disable a key if the project is canceled or is not longer in use.