Adding Payments
Charge for your product with Stripe and AI.
Adding Payments is a free Vibe Coding lesson on CoddyKit — lesson 3 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Vibe Coding learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Getting Paid
A validated product that people love can become a business — the moment you let them pay. Charging money is also the ultimate validation: nothing proves value like a credit card.
The good news: you don't need to be a payments expert. Stripe handles the hard, scary parts (cards, security, taxes), and AI can wire it into your app step by step. In this lesson you'll add payments the vibe-coding way.
Why Stripe
Stripe is the default choice for indie makers. It's developer-friendly, handles cards from around the world, manages security and compliance, and has world-class docs that AI tools know deeply.
You'll work with a few core ideas: Products (what you sell), Prices (how much, one-time or recurring), Checkout (the payment page), and webhooks (Stripe telling your app a payment happened).
You don't memorize these — you ask AI to set them up.
Start with a Payment Link
The absolute fastest way to get paid needs zero code: a Stripe Payment Link. You create a product in the Stripe dashboard, get a URL, and put it behind a button.
This is perfect for an early MVP — validate that people will actually pay before you build real billing into the app.
I want the simplest possible way to charge $9/month for my web app's Pro plan.
- Walk me through creating a Stripe Payment Link in the dashboard (no coding)
- Show me how to add it as an 'Upgrade to Pro' button in my HTML
- Explain what happens after the user pays and how I'd know they paid
Keep it shippable today; I'll add automation later.One-Time vs Subscription
Decide how you charge before you build. One-time payments suit a single purchase (a template, a course, lifetime access). Subscriptions charge on a recurring schedule (monthly or yearly) — the model behind most SaaS.
Subscriptions give predictable, recurring revenue but add complexity: renewals, cancellations, failed payments. For a first paid product, many makers start with a simple monthly plan plus a discounted yearly option.
Add Stripe Checkout with AI
When you outgrow Payment Links, move to Stripe Checkout: a secure, Stripe-hosted page your app sends users to. Your server creates a "checkout session," and Stripe handles the rest.
Ask AI to scaffold both the backend route and the frontend button. Be specific about your stack so the code fits.
Add Stripe Checkout to my app (Node.js + Express backend, plain JS frontend).
1. A backend route POST /create-checkout-session that creates a subscription Checkout session for my $9/month price.
2. A frontend 'Upgrade' button that calls it and redirects the user to Stripe.
3. Use my Stripe secret key from an environment variable, never hardcoded.
4. Explain each part as you go.Confirm Payments with Webhooks
How does your app know a payment succeeded? Stripe sends a webhook — an automatic message to your server when events happen (like checkout.session.completed).
This is where you flip a user to "Pro." Here's the shape of handling a webhook event in JavaScript — simplified so you can see the logic AI generates.
function handleStripeEvent(event) {
if (event.type === 'checkout.session.completed') {
const userId = event.data.object.client_reference_id;
upgradeToPro(userId);
return 'upgraded ' + userId;
}
return 'ignored ' + event.type;
}
function upgradeToPro(userId) {
console.log('User', userId, 'is now Pro');
}
const fakeEvent = {
type: 'checkout.session.completed',
data: { object: { client_reference_id: 'user_42' } }
};
console.log(handleStripeEvent(fakeEvent));Test Mode First, Always
Stripe has a test mode with fake API keys and fake cards (like 4242 4242 4242 4242). Never test with real money on yourself.
Build and verify the entire flow in test mode: checkout, webhook, the upgrade, and cancellation. Only switch to live keys once it all works. Ask AI for the test card numbers and how to trigger test webhooks.
I've added Stripe Checkout. Help me test it safely before going live.
- Confirm I'm using TEST keys, not live keys
- Give me Stripe's test card numbers for success and for a declined card
- Show me how to test that my webhook actually upgrades the user
- Give me a checklist to verify before flipping to live modeGuard Your Keys
Your Stripe secret key can move real money — treat it like a password. It belongs only on your server, loaded from an environment variable, never in frontend code, never in a Git commit, and never pasted into a public prompt.
The frontend may use the publishable key (safe to expose). If a secret key ever leaks, roll it immediately in the Stripe dashboard. Ask AI to audit your code for accidentally exposed keys.
Gate Pro Features
Once a user is Pro, your app needs to unlock the right things. The pattern: store an isPro flag on the user, then check it before showing premium features or running paid actions.
Always enforce the check on the server too — a frontend-only gate can be bypassed. Ask AI to add the flag and the checks consistently across your app.
After a successful Stripe payment, my webhook sets user.isPro = true.
Now help me gate Pro features:
- Show the pattern for checking isPro before allowing a premium action
- Make sure the check runs on the SERVER, not just hidden in the UI
- Add a friendly 'Upgrade to unlock' message for free users
- Where should I store the isPro flag in my database?Handle the Messy Cases
Real billing has edges: cards get declined, users cancel, subscriptions lapse, people ask for refunds. A trustworthy product handles these gracefully.
Plan for: failed renewals (downgrade after a grace period), cancellations (keep access until the period ends), and refunds (revoke Pro). Stripe sends webhooks for each. You don't have to handle every case on day one — but ask AI which ones matter most for your model and tackle those first.
Payments, the Indie Way
Your path to getting paid:
- 1. Start with a no-code Payment Link to validate willingness to pay.
- 2. Upgrade to Stripe Checkout when ready.
- 3. Confirm payments with webhooks and flip users to Pro.
- 4. Test everything in test mode first.
- 5. Guard your secret key on the server only.
- 6. Gate features and handle cancellations.
AI writes most of this for you — your job is to understand the flow and keep it secure.
Quick Check
Where should your Stripe secret key live?
Recap: Charge with Confidence
You learned to add payments with Stripe and AI:
- Start with a no-code Payment Link to validate demand.
- Choose one-time vs subscription pricing.
- Use Stripe Checkout and webhooks for the full flow.
- Always test in test mode before going live.
- Keep your secret key server-side and gate Pro features.
- Plan for cancellations, failed payments and refunds.
You can now make money. Final lesson: launching your SaaS to the world.
Frequently asked questions
Is the “Adding Payments” lesson free?
Yes — the full text of “Adding Payments” is free to read here on the web, and the Vibe Coding course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Vibe Coding course, upgrade to CoddyKit PRO.
What will I learn in “Adding Payments”?
Charge for your product with Stripe and AI. You practise Vibe Coding with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Vibe Coding?
No prior experience is required. Vibe Coding on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 4, so you can start here or from the beginning and move at your own pace.
How long does the “Adding Payments” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Vibe Coding lesson?
Yes. Every Vibe Coding lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.