To get the Publishable Key and the Secret Key from Stripe, you need an account at Stripe (www.stripe.com).
1. Open the following website www.stripe.com and click on "Sign in".
2. Now that you have logged in to Stripe, the dashboard opens. In the left menu, first click on "Developers" and then on "API keys".
Retrieve Publishable Key and Secret Key
3. Once you have clicked on "API keys", the page with the API keys opens. Under Standard Keys you will see the Publishable Key and above the Secret Key there is a button "Reveal live key token". Now click on it to display the secret key.
Sandbox and Live mode
To switch Stripe to the Sandbox (Test Payments) mode or Live (Real Payments) mode, click on "View test data" in the left menu. Note that Sandbox and Live Mode have different keys.