import initial variables into spider before execution

I have managed to upload and deploy my first spider to ScrapingHub and all is working very well.

In the project we intend to use the service we require the ability to change/modify variables in the spider before it is run.

Is this possible through the API and if so could you explain how this is implemented?

The intention is to change the initial data for the spider before it is executed.

Kind regards,

Leon