We've released our new Accounting Extension API in to public beta. This API makes it easier for users to connect their accounting system to HubSpot. As always with public beta, we're releasing this new to get public feedback. It is not intended for use in production applications, as it is subject to change at any time. We'll send an update when it is released to general availability.
If you have any questions or comments, please feel free to leave a message on the forum thread.