The builder is a sketchpad for relationships, not a full genealogy database. It keeps names, sex, birth and death years, notes, and the links between parents, children and partners. Parent links can be biological, adoptive, step or foster, and Kinage names each one correctly.

Trees are stored in your browser and never uploaded, so there is no account and no way for anyone else to see them. Back up by exporting a file. Read keeping a family tree private and GEDCOM explained for the details, or how to start a family tree if you are new to this.