Does Solid prevent end-users from getting double charges? 

Yes, Solid has protection from double charges under the hood. 

How does it work? 

    For 1st payments

    - It does not matter how many times the end-user clicks the "pay" button. One payment form can perform only one payment at a time. 


    For subscription payments

    - Our system checks a user_id for active subscriptions, and if product_id (subscription product) of active subscription matches the one you are sending in an order for subscription activation, Solid will decline the order with a 2.14 - Subscription error decline code. In other words - the user is already subscribed to the product.