> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://developer.americanexpress.ferndocs.com/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://developer.americanexpress.ferndocs.com/_mcp/server.

# Payment Account Reference

> **Note**
>
> American Express publishes an overview for this product but no API
> specification, so there is no endpoint reference to show.

Payment Account Reference (PAR) provides an aggregated view of a Card Member's account activity across different payment formats. Developed by EMV Co, it is a non-financial reference generated by American Express Network Services that is associated with a Primary Account Number (PAN). PAR links the PAN and associated tokens to allow acquirers and Merchants to comply with their obligations and provide value-added services to Card Members.

## Why it's great

#### Enhanced Fraud Controls

#### Account Management and Customer Service

## How it works

#### Through this API, the Merchant requests a PAR for a Card Member's 15-digit American Express Account Number

Through this API, the Merchant requests a PAR for a Card Member's 15-digit American Express Account Number.

![](/_fern-img/777b52f923bdf619592ad66e9fa5122bfd07f809b25b24999edb48b067131ec0.webp)

#### American Express returns a PAR

American Express returns a PAR.

![](/_fern-img/7d091d7b4c590efdbf399d1c27ceff8faaeda6a57b20c4e6a516103a79aa47fc.webp)

#### The Merchant uses the PAR to link the different Card numbers associated with an Account

The Merchant uses the PAR to link the different Card numbers associated with an Account.

![](/_fern-img/ea8656d1011c467f90a851a38b3be596524608843abe2b2eae1a3c9c162ba27c.webp)

## Technical Highlights

* The PAR value for an account remains the same throughout the life-cycle.
* Leverages Public (Client ID) and Private (Secret) key pair and HMAC Authentication.
* Encrypted communication via TLS.
* Restful API with JSON format for data exchange.

## What You Need To Go Live

* Comply with the use-cases outlined in Why It is Great.
* Terms and Conditions provided by Client Manager or Payment Consultant must be signed by an Authorized Signatory
* Adhere to the SDLC process within American Express for Developers
* Protect data using standard information security methods the same way they would protect other American Express data, according to local and regional laws and regulations.