Yes, it is secure. Stripe is certified to PCI Service Provider Level 1. This is the most stringent level of certification available. When you use PayNow for Stripe, no card data (or other sensitive data) is ever stored on your device – the app uses Stripe’s mobile library to convert card data to a single-use token which is then safely and securely passed to the Stripe server for processing as a card-not-present (CNP) transaction. To learn more, visit Stripe’s documentation and security practices.