1. Create a Stripe account and grab your API keys. You get a publishable key (safe to expose in frontend code) and a secret key (server-side only), each with a separate test and live version. Everything gets built and tested against the test keys first.
2. Decide how much of the checkout flow you're building yourself. Stripe Checkout is the hosted, prebuilt page; it's the fastest path and covers most businesses. Stripe.js and Elements are what you use instead when you need the payment form embedded directly in your own page rather than redirecting to Stripe's.
3. Install Stripe's SDK for your stack (Node, Python, Ruby, PHP, Java, and others are all officially supported) on the server side, and load Stripe.js on the client side if you're building a custom form.
4. Create a PaymentIntent on your server for each payment attempt, then confirm it on the client using Stripe.js, which is what actually prompts and processes the card details without them passing through your own backend.
5. Set up webhooks. Stripe sends events like a succeeded or failed payment to an endpoint you control, which is how your system finds out what happened asynchronously, including cases where the customer never comes back to your confirmation page at all. Verify every webhook's signature; skipping that step is how fake webhook calls get taken seriously.
6. Test with Stripe's test card numbers before switching to live keys. You can simulate a successful charge, a decline, and most of the specific error cases Stripe defines, all without moving real money.