solidtime is a modern open-source time tracker. Features

Time tracking: Track your time with a modern and easy-to-use interface Projects: Create and manage projects and assign project members Tasks: Create and manage tasks and assign tasks to project members Clients: Create and manage clients and assign clients to projects Billable rates: Set billable rates for projects, project members, organization members and organizations Multiple organizations: Create and manage multiple organizations with one account Roles and permissions: Create and manage organizations Reporting: Analyze your team's tracked time with dynamically generated charts with many filters and grouping options Import: Import your time tracking data from other time tracking applications (Supported: Toggl, Clockify, Timeentry CSV)