Store compound credintilas structure (JSON object)

hey guys
i want to store credentials (key and secret) for every partner in my system, for example: for partner with id “aaaa-bbbb-cccc-dddd”, I want to store a key and secret - {key: “aaa”, secret:“dddd”}.
i thought about using vault secrets but the client libraries doesn’t support it, i could using the API instead.
how should i store json object? should i use vault or vault secrets for it?