From MatrixStore v4, we provide a REST API that can be used to manage your MatrixStore including users and vaults.
You can download the current documentation for the MatrixStore Management REST API for you MatrixStore version from the below links
MatrixStore v4.2: Includes Space Management and Hybrid Vaults, download here
MatrixStore v4.1: Includes Application Capabilities, download here
MatrixStore v4.0: Initial version, download here
In addition, we have setup a guide using cURL providing some basic examples on how to interact with the MatrixStore Management REST API, which can be downloaded from here