How long is the warranty for the S700 device?

Mint provides a one-year limited warranty against defective materials and faulty workmanship.

The warranty period starts on the date of your original purchase of the terminal, and ends one year after that date. It's also worth noting that this limited warranty applies only to unaltered hardware components of the terminal that are used in accordance with these Purchase Terms and not subject to accident, misuse, or neglect.