Stripe — Accept payments

What you get

Stripe is the internet's standard for accepting credit cards. Once connected, prompts like “add a $10/month pro plan” auto-create the products, prices, and payment links in YOUR Stripe dashboard, and Marnix wires up the checkout buttons in your app. Money goes directly to your Stripe account — we never touch it.

When you'd reach for this

• Paid SaaS with Free / Pro tiers — “add a free plan with 10 uses and a $20/month Pro with unlimited uses. Show a pricing page and an upgrade button.”
• Digital products — “let people buy my Notion template for $15 with a payment link. Email them the download after payment.”
• Donation button — “add a ‘Tip the developer’ button that lets people pay any amount from $1 to $100.”
• Course / event tickets — “sell 200 early-bird tickets at $49 and then switch to $79. Collect name + email at checkout.”
• Marketplace commission — “take a 10% cut on every booking and route the rest to the seller’s Stripe Connect account.”
• Metered usage / credits — “charge $5 for 100 AI-image credits. Top-up button, Stripe webhook updates their balance.”

How to connect

1. Stripe account (free)

Sign up at dashboard.stripe.com/register. You can use test mode immediately; go through activation (legal entity, bank account) when you're ready to accept real money.

2. Create a restricted API key

Go to dashboard.stripe.com/apikeys → “Restricted keys” → + Create restricted key. Name it “Marnix” and grant these permissions:

• Write: Customers, Products, Prices, Payment Links, Invoices, Subscriptions, Coupons, Refunds
• Read: Payment Intents, Balance

Copy the rk_test_... (test mode) or rk_live_... (production) key.

3. Paste in Marnix

Open Integrations → Accept payments, paste the restricted key, click Connect. Marnix detects test vs live mode from the key prefix and shows a badge on the connector tile.

Example prompts

• “Add a pricing page with Free / Pro ($20/mo) / Business ($50/mo). Upgrade button opens Stripe checkout.”
• “Let me sell my ebook for $15 with a payment link. Email the PDF after purchase.”
• “Add a subscription status banner — if the user's subscription is past_due, show a ‘Update payment method’ link to Stripe Customer Portal.”
• “Build a tipping jar — $3 / $10 / $25 preset buttons plus a custom amount field.”
• “Add a coupon code input at checkout.”

Test mode vs live mode

Start with rk_test_ — all the prompts above work, but charges don't actually run. Use Stripe's test card 4242 4242 4242 4242 (any future date, any CVC) to simulate successful payments. When you're ready for real money, disconnect, create a live restricted key, and reconnect. Your app code doesn't change.

Troubleshooting

• “create_checkout_session not available” — correct, Stripe's MCP doesn't expose that tool yet. Marnix uses create_payment_link instead, which covers the same use case.
• Key doesn't work after a few weeks — Stripe auto-rotates some keys. Regenerate the restricted key and reconnect.