You can set launch parameters for your Streams from Streams Dashboard and also via URL Parameters.
URL Parameters will allow you to apply Launch Parameters for each Stream Sessions. If you are looking for a solution to push parameters for each Visitor (Stream Session) it will be a good fit for you.
If you need to push static parameters for your application (connection port values, screen mode, screen size, etc.) you can directly set those launch parameters via Streams Dashboard.
The launch parameters you configured will be applied while your application is running on Vagon Streams.
Launch Parameters may cause initialization issues when they are configured wrong. Be sure that your configuration has been tested locally before applying those parameters to your Vagon Streams experience.