I don’t do much backend work at the moment but I found using JSONB fields for prototyping endpoints to be quite handy. Once I had a feature figured out and working, I’d create a proper schema.
I've found Postgres' Hstore type useful for this, too.
I often create a "metadata" hstore field on a table and use it for random bits of data I don't want to create an actual field for yet. When I find that the application needs that bit of data and in a certain format, I'll move it into an actual field.
I get that, but I think the temptation to add too much structure to the JSONB would be too great; this is just a temporary or prototype field, so it just needs a name and a value. Hstore works great for this.
