You will not be charged during the trial period and if you continue on with us, you'll only be charged based on what you use after the trial period.
Our payment processor, Stripe, will run an active card check on your card when you sign up for a trial.
This helps Stripe to verify your identity, and checks that the card you have signed up with is active (i.e. not fake or expired). This ensures both our software and our customers are protected from malicious or spam sign ups.