Log in to your Stripe Dashboard and navigate to the Developers section to find your "Test Secret Key" ( sk_test_... ).

: Treat an SK key like a master password. It should never be committed to public repositories (like GitHub) or embedded in client-side code.

Stripe provides two types of API keys—Publishable Keys (PK) and Secret Keys (SK). The Secret Key is used on the server side to perform high-privileged actions, such as creating charges, issuing refunds, and validating payment methods.

Used strictly in secure, back-end server environments. An SK key possesses full authorization to perform API actions, including creating charges, issuing refunds, and retrieving customer data. How "CC Checkers" Attempt to Use SK Keys

The tool sends a request to Stripe’s PaymentIntents or Sources API using the provided SK key.