Stripe is a payment processing platform. Merchants integrate Stripe into their websites and apps to accept payments from customers. When a customer enters their credit card on a merchant's checkout page, the payment data flows through Stripe's API to the card network (Visa, Mastercard, etc.), then to the issuing bank for authorization.

The payment flow works like this: the customer submits payment details, Stripe tokenizes the card data, creates a PaymentIntent, sends an authorization request to the card network, the issuing bank approves or declines, Stripe notifies the merchant via webhook, and the merchant fulfills the order. Settlement happens 2 business days later when funds transfer from the issuing bank through the card network to the acquiring bank and finally to the merchant's bank account.

Stripe charges merchants a fee of 2.9% + 30 cents per successful transaction. Failed transactions are not charged. Merchants can issue refunds within 120 days. Disputed transactions (chargebacks) incur a $15 fee and are resolved through an evidence submission process.

Stripe also provides fraud detection (Radar), subscription billing, invoicing, and a dashboard for merchants to manage their payments.