Extension Payment Integration

Integrate payment/subscription into a Chrome extension. Ask user for provider, then fetch docs and implement.

Workflow (Execute This)

Step 1: Ask user for payment requirements

Ask the user to confirm:

1. Payment model: One-time purchase / Subscription / Freemium / Credits-based
2. Provider category: Payment Gateway or Merchant of Record (MoR)?
3. Preferred provider (or let us recommend)
4. Required info: API keys, product/price IDs, webhook URL

Recommend MoR for solo/indie developers — handles tax, compliance, billing portal. No need to register as a business in every country.

Step 2: Provider selection guide

Category	Provider	Best For	Docs
MoR	Paddle	SaaS subscriptions, global tax	https://developer.paddle.com
MoR	Lemon Squeezy	Indie/solo devs, simple setup	https://docs.lemonsqueezy.com
MoR	Polar	Open source monetization	https://docs.polar.sh
MoR	Creem	Extension-focused MoR	https://docs.creem.io
MoR	Dodo Payments	Simple digital products	https://docs.dodopayments.com
MoR	FastSpring	Enterprise digital commerce	https://developer.fastspring.com
MoR	Gumroad	Creators, digital products	https://help.gumroad.com
Gateway	Stripe	Full control, most flexible	https://docs.stripe.com
Gateway	PayPal	Wide user base, easy checkout	https://developer.paypal.com/docs
Gateway	Razorpay	India-focused payments	https://razorpay.com/docs
Gateway	Square	POS + online	https://developer.squareup.com/docs
Gateway	Adyen	Enterprise, multi-currency	https://docs.adyen.com
Gateway	Braintree	PayPal-owned, cards + PayPal	https://developer.paypal.com/braintree/docs
Gateway	Authorize.Net	US legacy, reliable	https://developer.authorize.net

llms.txt for AI-assisted docs (use docs-seeker skill):

• Stripe: https://docs.stripe.com/llms.txt
• Polar: https://docs.polar.sh/llms-full.txt

Step 3: Fetch provider docs

Use docs-seeker skill to fetch the provider's latest API docs. For Stripe/Polar, use llms.txt endpoints.

Step 4: Implement the integration

See references/integration-architecture.md for the full pattern.

Key architecture (extensions cannot run backend code):

Extension (popup/options) → Your Backend API → Payment Provider
         ↕                        ↕
   chrome.storage          License/subscription DB

Step 5: Show user the post-integration workflow

After integration, show the user this flow:

User clicks "Upgrade" in extension
  → Opens payment page (provider-hosted or custom)
  → Completes payment
  → Webhook hits your backend
  → Backend validates + stores license
  → Extension checks license via API
  → Premium features unlocked

References

• references/integration-architecture.md — Backend setup, license validation, webhook handling
• references/mor-vs-gateway.md — MoR vs Gateway decision guide, tax/compliance
• references/extension-licensing-patterns.md — License key, account-based, feature flags
• references/provider-quickstarts.md — Quick setup for top 5 providers

Related Skills

• extension-publish — Store submission and listing
• extension-analyze — Security audit (API key exposure check)
• extension-dev — Feature development workflow