I think they are the fastest to date. In terms of speed, SuperAnnotate beats out most of the competitors in the space. I love their automatic segmentation tool.

SuperAnnotate: A great tool for data annotation SuperAnnotate is an awesome tool for the researchers/students who are working with the dataset preparation for computer vision related applications such as environment perception including object detection and semantic segmentation. It helped me a lot in my Masters' thesis. Recommended.

I especially like the ability to draw… I especially like the ability to draw contours by just dragging the mouse-cursor or apple-pencil. It's a life saver compared to free tools like VGG-VIA.

An outstanding solution for image annotation Superannotate provides an online platform that represents a very powerful instrument for image annotation. It allows people to work together on the same project and check the quality of the annotations. Among the tools it provides, the “Smart Segmentation” option is excellent! It guides annotators during the labeling and speeds up the process a lot.

Excellent annotation tool I tried the free desktop tool. It works really well! Pleasant, intuitive, fast, it can definitely serve for small to medium size projects, as advertised. The annotations are accurate, the .json format to save them is perfectly appropriate. I'll give it 5 stars when it is possible to annotate videos rather than just images. Great tool anyway! [EDIT September 2021] Video annotation is now available, it really is a perfect tool, 5 stars without doubt!