The instances json file contains 5 main entries, 3 out of which contain the relevant information for a label upload (images, annotations, categories). The images list contains all images of the dataset with their metadata. The categories entry contains all categories with their relevant subcategories. The annotations' entry is the most important part as it lists all geometry labels (bbox and polygon) for the images. Use our coco class with its add_object_detection_data method to prepare the instances json for upload. When calling this function you can choose to either prepare the bbox annotation or the contained polygon for upload.