Shopify Payments Integration

Before writing code

Fetch live docs:

1. Web-search site:shopify.dev payments apps api for Payment Apps API
2. Web-search site:shopify.dev billing api app charges for app billing
3. Web-search site:shopify.dev shopify payments for Shopify Payments overview
4. Web-search site:shopify.dev payment session resolve reject for payment session flow
5. Web-search site:shopify.dev app subscription create usage record for billing mutations

Shopify Payments

Shopify's built-in payment processor (powered by Stripe):

• No third-party gateway needed
• Supports credit/debit cards, Shop Pay, Apple Pay, Google Pay
• Lower transaction fees than third-party gateways
• PCI DSS Level 1 compliant (Shopify handles compliance)

Payment Flow

Customer → Checkout → Payment Method Selection → Authorization → Capture

• Authorization happens at checkout
• Capture happens when order is fulfilled (or immediately, based on settings)
• Auto-capture can be enabled for immediate charge

Supported Payment Methods

Fetch live docs for supported payment methods by country — availability varies by region and changes over time.

Payment Apps API

For building custom payment gateways as Shopify apps:

Payment Session Flow

1. Customer selects your payment method at checkout
2. Shopify creates payment session → calls your app's payment endpoint
3. Your app processes payment with your gateway
4. Return: RESOLVE (success) or REJECT (failure)
5. Optional: REDIRECT for additional auth (3D Secure, bank redirect)
6. Optional: CONFIRM for pending/async payments

Key Mutations

Fetch live docs for each session mutation's input fields and the PaymentSessionActionsRedact webhook — the API surface for payment apps is complex and version-sensitive.

Payment App Requirements

• Must handle: payments, refunds, captures, voids
• Must implement: payments_app_configure GraphQL mutations
• Must respond within timeout (usually 5 seconds for sync, longer for async)
• Testing: use Shopify's test mode and development store

Fetch live docs: Web-search site:shopify.dev build payment extension for current extension configuration, required endpoints, and testing procedures.

Billing API

For charging merchants for your app:

Charge Types

Subscription Flow

1. Create subscription with appSubscriptionCreate → returns confirmationUrl
2. Redirect merchant to confirmationUrl
3. Merchant approves charge on Shopify-hosted page
4. Shopify handles billing, invoicing, and payouts to your Partner account

Usage-Based Billing Pattern

1. Create a subscription plan with a usage pricing model via appSubscriptionCreate
2. As the merchant uses features, record usage with appUsageRecordCreate
3. Shopify bills the merchant at the end of the billing cycle based on recorded usage
4. Capped amounts prevent unexpected charges

Fetch live docs for AppSubscriptionInput and AppUsageRecordInput fields — pricing models, trial days, currency options, and line item structures change across API versions.

Refund Processing

• Refunds issued via refundCreate mutation (on orders)
• Payment apps handle refund sessions via refundSessionResolve/refundSessionReject
• Can be full or partial
• Refunded to original payment method
• Refund notification sent to customer automatically

PCI Compliance

Shopify handles PCI compliance for:

• Shopify Payments (fully managed)
• Checkout-hosted payment forms
• Payment apps that use Shopify's session-based flow

Your app must:

• Never store raw card numbers, CVV, or sensitive cardholder data
• Use Shopify's payment session API (not direct card collection)
• Follow Shopify's security requirements for payment apps
• Implement HTTPS for all endpoints

Best Practices

• Recommend Shopify Payments as primary gateway (lowest fees, best integration)
• Use the Payment Apps API for custom gateways — never collect cards directly
• Implement proper error handling for payment sessions (timeouts, network errors)
• Use the Billing API for app monetization — never handle payments outside Shopify
• Test payment flows in development stores (test mode)
• Handle refunds gracefully — always confirm with refundSessionResolve
• Implement idempotency for payment operations (use idempotency keys)
• Log payment events for debugging but never log sensitive payment data

Fetch the Shopify Payment Apps API and Billing API documentation for exact session flow, mutation inputs, testing procedures, and webhook requirements before implementing.