> The JSONB format is not intended as an interchange format. Nevertheless, JSONB is stored in database files which are intended to be readable and writable for many decades into the future. To that end, the JSONB format is well-defined and stable. The separate SQLite JSONB format document provides details of the JSONB format for the curious reader.

And indeed the functions jsonb() and json() will let you convert to and from jsonb.