I would like to label character data with BIO tags as part of an active learning process on unlabelled data. I am assuming there are open source GUI tools available which I can use to make this easier - i.e. present the string to be labeled and some way of tagging characters from a predefined set of tags (and probably allow new tags to be added).
I have not been able to find anything though - ideally cross-platform (Linux and macOS at a minimum). It could be a cloud service or AWS product but I'd prefer something which is locally installed.
Does anyone know of such a thing? Even something as simple as search term would help.