PostAuthenticate RPC

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title: PostAuthenticate description: Validate authentication results with the issuing bank and confirm payment can proceed last_updated: 2026-03-11 generated_from: backend/grpc-api-types/proto/services.proto auto_generated: false reviewed_by: engineering reviewed_at: 2026-03-05

approved: true

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Overview

The PostAuthenticate RPC validates 3D Secure authentication results with the issuing bank. After the customer completes a challenge (if required), this RPC confirms the authentication was successful and returns the data needed to proceed with payment authorization.

Business Use Case: After the customer returns from a 3DS challenge or after a frictionless authentication, you need to validate the results before processing the payment. This RPC confirms the authentication and provides the ECI and CAVV values required for liability shift.

Purpose

Why post-authenticate?

Scenario	Action
After challenge completion	Validate the authentication response
Before payment	Confirm authentication succeeded
For liability shift	Obtain ECI/CAVV values

Key outcomes:

Authentication validated
ECI and CAVV values returned
Ready for payment authorization

Request Fields

Field	Type	Required	Description
`merchant_order_id`	string	Yes	Your unique order reference
`amount`	Money	Yes	Transaction amount
`payment_method`	PaymentMethod	Yes	Card details
`customer`	Customer	No	Customer information
`address`	PaymentAddress	Yes	Billing address
`authentication_data`	AuthenticationData	No	3DS result data from challenge
`connector_order_reference_id`	string	No	Connector's order reference
`metadata`	SecretString	No	Additional metadata
`connector_feature_data`	SecretString	No	Connector-specific metadata
`return_url`	string	No	URL to redirect after authentication
`continue_redirection_url`	string	No	URL to continue after redirect
`browser_info`	BrowserInformation	No	Browser details

Response Fields

Field	Type	Description
`connector_transaction_id`	string	Connector's authentication transaction ID
`status`	PaymentStatus	Current status: AUTHENTICATED, FAILED
`error`	ErrorInfo	Error details if validation failed
`status_code`	uint32	HTTP-style status code
`response_headers`	map	Connector-specific response headers
`redirection_data`	RedirectForm	Additional redirect if needed
`network_transaction_id`	string	Card network transaction reference
`merchant_order_id`	string	Your order reference (echoed back)
`authentication_data`	AuthenticationData	Validated 3DS authentication data
`incremental_authorization_allowed`	bool	Whether incremental auth is allowed
`state`	ConnectorState	State for payment authorization
`raw_connector_response`	SecretString	Raw response for debugging

Example

Request (grpcurl)

grpcurl -H "x-connector: stripe" \
  -H "x-connector-auth: {\"Stripe\":{\"api_key\":\"$STRIPE_API_KEY\"}}" \
  -d '{
    "merchant_order_id": "order_001",
    "amount": {
      "minor_amount": 10000,
      "currency": "USD"
    },
    "payment_method": {
      "card": {
        "card_number": "4242424242424242",
        "expiry_month": "12",
        "expiry_year": "2027"
      }
    },
    "address": {
      "billing_address": {
        "line_1": "123 Main St",
        "city": "San Francisco",
        "country": "US"
      }
    },
    "authentication_data": {
      "eci": "05",
      "cavv": "AAABBIIFmAAAAAAAAAAAAAAAAAA="
    }
  }' \
  localhost:8080 \
  ucs.v2.PaymentMethodAuthenticationService/PostAuthenticate

Response

{
  "connector_transaction_id": "pi_3Oxxx...",
  "status": "AUTHENTICATED",
  "authentication_data": {
    "eci": "05",
    "cavv": "AAABBIIFmAAAAAAAAAAAAAAAAAA=",
    "trans_status": "Y"
  },
  "incremental_authorization_allowed": false,
  "status_code": 200
}

Next Steps

Payment Service - Authorize payment with 3DS data

Post-authenticate