Highrise is not involved in the development of any outside integrations. Each integration is handled from start to finish by the other company using the Highrise API.
Many companies offer useful integrations to Highrise from their applications. You can see a full list on our Extras page.
Many of our customers use these integrations with their Highrise accounts.
Our friends at Zapier put together a few guides about how it can help you do even more with your Highrise account.