> ## Documentation Index
> Fetch the complete documentation index at: https://yn-c9bb3266.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# ECI Indicators

> Electronic Commerce Indicator values and their meaning for 3DS transactions

## What is ECI?

The Electronic Commerce Indicator (ECI) is a value returned during 3D Secure (3DS) authentication that indicates the level of security applied to a card transaction. The ECI value determines whether the transaction qualifies for a liability shift from the merchant to the card issuer in case of a fraud-related chargeback.

ECI values are set by the card issuer's Access Control Server (ACS) during the 3DS authentication process and are included in the authorization request sent to the acquirer.

## ECI Values by Card Network

Each card network defines its own ECI values. The meaning is consistent across networks, but the numeric codes differ between Visa/Amex and Mastercard.

| Authentication Result                                                   | Visa | Mastercard | Amex | Liability Shift           |
| ----------------------------------------------------------------------- | ---- | ---------- | ---- | ------------------------- |
| Fully authenticated (3DS challenge completed)                           | `05` | `02`       | `05` | Yes. Shifts to issuer     |
| Attempted authentication (merchant attempted, issuer not participating) | `06` | `01`       | `06` | Yes. Shifts to issuer     |
| Non-3DS / authentication failed / not attempted                         | `07` | `00`       | `07` | No. Remains with merchant |

## Detailed ECI Reference

### Visa / Amex

| ECI  | Meaning                  | Description                                                                                                                                         | Liability Shift |
| ---- | ------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------- | --------------- |
| `05` | Fully Authenticated      | Cardholder successfully completed 3DS authentication. The issuer verified the cardholder's identity through a challenge (password, OTP, biometric). | Yes             |
| `06` | Attempted Authentication | The merchant attempted 3DS authentication, but the issuer or card was not enrolled in 3DS. The attempt is recorded for liability purposes.          | Yes             |
| `07` | Non-3DS Transaction      | No 3DS authentication was performed or authentication failed. The transaction proceeds without 3DS protection.                                      | No              |

### Mastercard

| ECI  | Meaning                  | Description                                                                               | Liability Shift |
| ---- | ------------------------ | ----------------------------------------------------------------------------------------- | --------------- |
| `02` | Fully Authenticated      | Cardholder successfully completed 3DS authentication via Mastercard Identity Check.       | Yes             |
| `01` | Attempted Authentication | Merchant attempted authentication, but issuer/card was not enrolled. Attempt is recorded. | Yes             |
| `00` | Non-3DS Transaction      | No authentication performed or authentication failed.                                     | No              |

## Liability Shift Implications

The liability shift is a key benefit of 3DS authentication. When liability shifts to the issuer, the merchant is protected from fraud-related chargebacks.

| Scenario                                       | Liability | ECI (Visa) | ECI (MC) |
| ---------------------------------------------- | --------- | ---------- | -------- |
| Customer completes 3DS challenge successfully  | Issuer    | `05`       | `02`     |
| 3DS attempted but issuer not participating     | Issuer    | `06`       | `01`     |
| No 3DS performed                               | Merchant  | `07`       | `00`     |
| 3DS authentication fails and merchant proceeds | Merchant  | `07`       | `00`     |

<Warning>
  Proceeding with a transaction after a failed 3DS authentication (ECI 07/00) means the merchant assumes full liability for fraud-related chargebacks. Evaluate your risk tolerance before processing these transactions.
</Warning>

## How ECI Affects Interchange Rates

Transactions with successful 3DS authentication (ECI 05/02) may qualify for lower interchange rates from some card networks and issuers, as the reduced fraud risk is factored into pricing. The exact interchange benefit varies by:

* Card network (Visa, Mastercard, Amex)
* Issuing region
* Merchant category
* Transaction type (e-commerce, recurring)

Transactions without 3DS (ECI 07/00) typically incur standard or higher interchange rates and may be subject to additional risk-based fees in regions where SCA (Strong Customer Authentication) is mandated, such as the European Economic Area under PSD2.

## ECI in the Yuno API Response

The ECI value is included in the payment response within the `three_d_secure` object after authentication is processed.

```json theme={"theme":{"light":"github-dark","dark":"github-dark"}}
{
  "transaction": {
    "three_d_secure": {
      "version": "2.2.0",
      "eci": "05",
      "authentication_status": "Y",
      "cavv": "AAABBJkZUQAAAABjRWWZEEFgFz8=",
      "ds_transaction_id": "a3b2c1d4-e5f6-7890-abcd-ef1234567890",
      "liability_shift": true
    }
  }
}
```

| Field                   | Description                                                            |
| ----------------------- | ---------------------------------------------------------------------- |
| `eci`                   | The Electronic Commerce Indicator value                                |
| `authentication_status` | `Y` = authenticated, `A` = attempted, `N` = failed, `U` = unavailable  |
| `cavv`                  | Cardholder Authentication Verification Value (proof of authentication) |
| `ds_transaction_id`     | Directory Server transaction identifier                                |
| `liability_shift`       | Boolean indicating whether liability shifted to issuer                 |

<Note>
  The `three_d_secure` object is only present when 3DS authentication was attempted. For non-3DS transactions, this object will be absent from the response.
</Note>