3 simple steps.
Users contact me , i provide a demo , if they like it i provide them a production account , they work for 1 month , if they are happy with the results they pay.
easy as 1-2-3
But what do you provide? The API, the integración code? The casino frontend?
And how complex is for the users to integrate those slots to their casino? Does they need to know some technical stuf about coding and server or any one can integrate your slots to their site?
Does they need a casino licence to integrate your slots?