Syncing Abacus and Highrise is currently on our roadmap.

Abacus uses expense data and employee profiles to automate expense creation, policies and approvals. We use multiple sources of data to draft more accurate expenses, making it easy for employees to submit. Expense policy rules are applied as expenses are created to prevent violations and warn employees of errors. Build specific routing rules to send each expense to the best suited approver.

Highrise is for lovers of simplicity - it will do what you need, no bells or whistles attached. Their straightforward, but powerful functions help you keep your business on track. Features include email, task and document management.