Timebutler offers fully fledged overtime management. Every employee can record their overtime and overtime reduction, and Timebutler automatically maintains the overtime account. You can require that [overtime requires approval(/overtime-management/overtime-and-time-off/overtime-requiring-approval/). With the help of [limits(/vacation-planner/settings/limits-and-minimum-availability-of-employees/), you can cap the maximum overtime balance.
Here you can find an overview of the overtime management features.