It depends on what you mean when you say "data type". Some databases like PostgreSQL, have a JSON data type that permits full text search, a binary storage mechanism, indexing, and full suite of operators to access the data. Maria doesn't yet have that. The data type specifically is being tracked by MDEV-9144.
Even that though, brings a very limited type to MySQL, from one of the bug maintainers,
JSON data type directly contradicts SQL standard, that says, that
JSON_* functions take a string as an argument. Also, speed-wise
MariaDB does not need binary JSON, according to our benchmarks, our
JSON parser is as fast on text JSON as MySQL on binary JSON. That is,
in MariaDB one could VARCHAR or TEXT for JSON. If a validation is
needed, one can do it with a CHECK constraint:
my_json_column TEXT CHECK (JSON_VALID(my_json_column))
We'll add JSON "type" for MySQL
From my reading, that's not exactly the point of binary JSON let's refer to the MySQL docs
The binary format is structured to enable the server to look up subobjects or nested values directly by key or array index without reading all values before or after them in the document.
jsonb does a lot more than that.
jsonb data is stored in a decomposed binary format that makes it slightly slower to input due to added conversion overhead, but significantly faster to process, since no reparsing is needed. jsonb also supports indexing, which can be a significant advantage.
tldr; Maria DB doesn't have a JSON type yet. Even when it gets the "type" it's just a thin wrapper over a text-validation (like PostgreSQL's
json type). There are no plans for a binary JSON type (like PostgreSQL's
jsonb) because the developers seemingly don't understand the advantages.