# Send payment method update email to customer

Triggers Shopify to send an email to the subscription customer with a secure link to update their payment method. This endpoint initiates Shopify's native payment update flow without requiring direct payment handling.

Key Features:
- Sends official Shopify payment update email to customer
- Customer receives secure link to Shopify-hosted payment update page
- No PCI compliance required - Shopify handles all payment data
- Supports all Shopify-supported payment methods
- Automatically updates subscription after customer completes the process

Process Flow:
1. API call triggers email send request to Shopify
2. Shopify sends branded email to customer's registered email
3. Customer clicks secure link in email
4. Customer authenticates on Shopify-hosted page
5. Customer adds/updates payment method
6. Subscription automatically uses new payment method

Email Details:
- Sent from Shopify's email servers
- Uses store's configured sender email
- Subject line typically: "Update your payment method"
- Contains secure, time-limited link
- Shopify-branded with store information

Use Cases:
- Failed payment recovery
- Expiring credit card updates
- Customer-requested payment changes
- Proactive payment method maintenance

Important Notes:
- Customer must have valid email address
- Email cannot be customized (Shopify template)
- Link expiration time set by Shopify
- Multiple emails can be sent if needed
- No webhook for completion - poll contract for updates

Rate Limiting:
- Subject to Shopify's email sending limits
- Recommended: Wait 24 hours between sends to same customer
- Excessive sends may be blocked by Shopify

Authentication: Requires valid X-API-Key header

Endpoint: PUT /api/external/v2/subscription-contracts-update-payment-method
Version: 0.0.1

## Query parameters:

  - `contractId` (integer, required)
    Subscription contract ID for payment method update. Must be a valid contract ID that belongs to the authenticated shop.
    Example: 123456789

  - `api_key` (string)
    API Key (Deprecated - Use X-API-Key header instead)

## Header parameters:

  - `X-API-Key` (string, required)
    API Key for authentication


## Response 200 fields

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## Response 422 fields