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Introduction

By default, when creating a subscription, Lago follows this process:

1. Creates and activates the subscription (unless scheduled for the future or it’s a downgrade);
2. Generates the invoice asynchronously; and
3. Processes the payment asynchronously.

This means it’s possible to create an active subscription for a customer even if the payment later fails. While this behavior is intentional, it may not be ideal for all use cases.

To address this, Lago now offers payment pre-authorization, allowing you to verify the validity of a payment method for a specific amount before creating the subscription.

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How pre-authorization Works

Pre-authorization creates a Payment Intent in Stripe to verify that the payment amount can be collected. When successful, the amount is temporarily held on the customer’s account but not captured.

Note: The held funds are automatically released immediately after successful verification.

Pre-authorization can fail for several reasons:

• Invalid card details;
• Insufficient funds; and
• 3D Secure authentication requirement.

Please note that if 3D Secure authentication is required, it may prevent subscription creation.

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Understanding the limitations

While pre-authorization helps reduce payment failures, it cannot guarantee successful invoice payment because:

1. Conditions may change between pre-authorization and actual payment:
   • Customer’s account balance may decrease
   • Card may be blocked or expired
2. A bank might approve the pre-authorization but still require 3D Secure authentication for the actual payment

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Implementation guide

To implement pre-authorization, use the POST /api/v1/subscriptions endpoint with additional parameters. The standard subscription parameters remain unchanged.

You must manually specify the amount to authorize, as the final amount (including taxes) is only calculated during invoice generation.

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Request format

{
  "authorization": {
    "amount_cents": 100,    // Amount in cents (e.g., 100 = 1 EUR)
    "amount_currency": "EUR"
  },
  "subscription": {
    // Standard subscription parameters
  }
}

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Response format

{
  "status": 422,
  "error": "Unprocessable Entity",
  "code": "provider_error",
  "provider": {
    "code": "stripe_code"
  },
  "error_details": {
    "code": "error_code",
    "message": "error_message",
    "request_id": "request_id",
    "http_status": "http_status",
    "http_body": {
      // Complete Stripe error response
    }
  }
}