Ganttic is an online tool for resource planning and project portfolio management. Created for people fed up with Excel, but not satisfied with a one-size-fits-all approach to resource management. Build plans and workflows from the ground up - no features or data are imposed. Schedule any resource type for any kind of booking. Create your own data fields to define your projects and teams. A single-purpose tool you can use independently or connected via API. Try it and see for yourself.
One of a few Gantt tools that have easy to use granular (15-min) task creation. However, it lacks automation, interactive reports and custom expressions in reports.