Sandtime.io is a time tracking app designed for small and medium-sized enterprises. It offers features such as timesheets, reporting, project management, team access controls, time rounding, multi-currency support, temporal cost and revenue rates, custom subdomain, browser extension, and Slack integration. The app allows for easy tracking of hours worked and automatic time registration at startup and shutdown. It also enables users to prepare invoices and reports using data collected by the app.