agmission/Development/server/docs/archived/PAYMENT_FAILURE_FIX_SUMMARY.md

Payment Failure Handling Fix - Documentation Update Summary

Date: January 8, 2026
Issue: Critical billing bug - subscriptions with partial discount coupons created as active without payment
Impact: Revenue loss, unauthorized free service access

Changes Made

1. Code Changes (controllers/subscription.js)

Direct Subscription Creation (Line ~2088) - UPDATED January 16, 2026

// ORIGINAL (Jan 8, 2026): payment_behavior: 'error_if_incomplete'
// UPDATED (Jan 16, 2026): Changed to support 3DS authentication
payment_behavior: 'default_incomplete'  // Allows 3DS flow without throwing errors

// NEW: Added 3DS detection helper (lines 1519-1643)
const handledSub = await handleSubscriptionPayment(subscription);
// Returns client_secret to frontend if 3DS required

SubscriptionSchedule Payment Verification (Lines 1365-1481)

• Automatic invoice finalization for draft invoices
• Payment status verification with 3 failure conditions:
  • requires_payment_method
  • requires_action
  • requires_confirmation
• Immediate subscription cancellation on payment failure
• Graceful error handling for already-deleted subscriptions
• Invoice voiding for cleanup

Error Constant Addition (helpers/constants.js Line 87)

PAYMENT_FAILED: 'payment_failed'

2. Documentation Updates

Updated Files

1. docs/PAYMENT_FAILURE_HANDLING.md

• ✅ Complete implementation documentation
• ✅ Updated deployment checklist (marked completed tasks)
• ✅ Root cause analysis with SubscriptionSchedules
• ✅ Code examples and test scenarios
• ✅ Webhook handling documentation
• ✅ Frontend integration guidelines

2. docs/PROMO_MANAGEMENT.md

• ✅ Added critical note about draft invoice handling
• ✅ Updated testing guide with payment failure scenarios
• ✅ Added test cases for failed cards
• ✅ Cross-reference to payment failure documentation

3. docs/SUBSCRIPTION_PROMO_INTEGRATION.md

• ✅ Added new section: "Payment Failure Handling"
• ✅ Updated table of contents
• ✅ Client-side error handling examples
• ✅ Payment failure test scenarios
• ✅ Error response format documentation

4. apidoc/api_errors.js

• ✅ Added PaymentFailedError definition
• ✅ Added InvalidPaymentMethodError definition
• ✅ Error response examples with .tag format

5. README.md

• ✅ Already contains link to Payment Failure Handling (marked CRITICAL)

3. API Error Definitions

Added to API documentation (apidoc/api_errors.js):

/**
 * @apiDefine PaymentFailedError
 *
 * @apiError payment_failed Payment failed or requires action. 
 *                          Customer must provide valid payment method.
 *
 * @apiErrorExample PaymentFailedError-Response:
 *   HTTP/1.1 410 Payment Required
 *   {
 *     "error": {
 *        ".tag": "payment_failed",
 *        "message": "Payment failed. Please add a valid payment method."
 *     }
 *   }
 */

4. Error Response Format

All payment failure errors now follow standardized format:

{
  "error": {
    ".tag": "payment_failed",
    "message": "Payment failed. Please add a valid payment method."
  }
}

Testing Requirements

Test Scenarios

1. Partial Discount with Failed Card

   • Coupon: 50% off
   • Card: 4000000000000341
   • Expected: Error response with .tag: "payment_failed"
   • Expected: No subscription created

2. 100% Discount (Free)

   • Coupon: 100% off
   • Card: Any (no payment required)
   • Expected: Success, subscription created

3. No Discount with Failed Card

   • Coupon: None
   • Card: 4000000000000341
   • Expected: Error response with .tag: "payment_failed"
   • Expected: No subscription created

4. Trial Subscription

   • Trial: Active
   • Card: Not required during trial
   • Expected: Success, subscription in trialing status

Test Cards

// Card that always fails
'4000000000000341' // Generic decline

// Card that requires 3D Secure
'4000002500003155' // Requires authentication

// Card that succeeds
'4242424242424242' // Always succeeds

Deployment Checklist

Completed

• Code updated with payment_behavior: 'error_if_incomplete' (Jan 8, 2026)
• Code UPDATED to payment_behavior: 'default_incomplete' (Jan 16, 2026 - 3DS support)
• Added handleSubscriptionPayment() helper for 3DS detection
• Invoice finalization implemented for SubscriptionSchedules
• Payment verification with 3 failure statuses added
• Graceful subscription deletion error handling
• PAYMENT_FAILED error constant added
• Documentation created and updated
• Webhook handlers verified (already correct)
• API error definitions updated
• All cross-references updated

Pending

• Test in Stripe test mode with failed cards
• Verify frontend displays error correctly
• Test email notifications for failed payments
• Monitor production for incomplete subscriptions after deployment
• Update customer support documentation

Files Modified

Code Files

1. controllers/subscription.js - Core payment logic
2. helpers/constants.js - Error constant

Documentation Files

1. docs/PAYMENT_FAILURE_HANDLING.md - Main documentation
2. docs/PROMO_MANAGEMENT.md - Promo system updates
3. docs/SUBSCRIPTION_PROMO_INTEGRATION.md - Client integration guide
4. apidoc/api_errors.js - API error definitions
5. docs/PAYMENT_FAILURE_FIX_SUMMARY.md - This summary (NEW)

Cross-References

All documentation files now properly cross-reference each other:

• README.md → Links to PAYMENT_FAILURE_HANDLING.md (CRITICAL)
• PAYMENT_FAILURE_HANDLING.md → Complete implementation details
• PROMO_MANAGEMENT.md → Links to PAYMENT_FAILURE_HANDLING.md
• SUBSCRIPTION_PROMO_INTEGRATION.md → Links to both payment and promo docs
• API Error Docs → Defines error response format

Frontend Integration Notes

Frontend teams should:

1. Handle payment_failed errors:

   if (error.response?.data?.error?.['.tag'] === 'payment_failed') {
     showError('Payment failed. Please update your payment method.');
     redirectToPaymentSettings();
   }
   

2. Test with Stripe test cards before production

3. Display clear error messages to users

4. Redirect to payment method update on failure

Additional Notes

Why This Fix Was Critical

1. Revenue Protection: Prevents customers from getting paid services without payment
2. Security: Closes loophole where failed payments weren't enforced
3. Compliance: Ensures proper payment collection for partial discounts
4. User Experience: Provides immediate feedback on payment failures

Technical Highlights

1. Dual-Path Solution:

   • Direct subscriptions: payment_behavior parameter
   • ScheduleSubscriptions: Manual invoice finalization

2. Comprehensive Failure Detection: Three payment intent statuses checked

3. Clean Cleanup: Automatic subscription deletion and invoice voiding

4. Graceful Error Handling: Handles race conditions with already-deleted resources

Support Resources

• Stripe Documentation: https://stripe.com/docs/billing/subscriptions/overview
• Test Cards: https://stripe.com/docs/testing#cards
• Payment Behavior: https://stripe.com/docs/api/subscriptions/create#create_subscription-payment_behavior

Questions or Issues?

Contact the backend team or refer to:

• docs/PAYMENT_FAILURE_HANDLING.md - Complete technical documentation
• docs/PROMO_MANAGEMENT.md - Promo system documentation
• docs/SUBSCRIPTION_PROMO_INTEGRATION.md - Client integration guide