EFT CPA 005 File Guide

The EFT CPA 005 file format is a Canadian formatting standard for generating electronic funds transfer files.

The EFT CPA 005 file format is a Canadian formatting standard for generating electronic funds transfer (EFT) files - sometimes known as PAD files - for pre-authorized transactions. Originally developed by the Canadian Payments Association for batched, inter-bank transactions, the CPA 005 format is defined as a 1464-byte text record.

Despite its widespread use, the official documentation from the CPA and various banks has been known to contain omissions, inconsistencies, and errors, which makes generating a fully compliant PAD file from scratch a challenge for developers.

EFT CPA 005 File History

Historically, the CPA 005 format was designed to handle thousands of transactions recorded on tape, with dedicated processing centers managing the physical tapes between banks. Not any bank could process these original transaction tapes, they would have to be physically taken to the major processing centers in major cities in Canada to be processed.

Today, while the physical tapes are a thing of the past, the format lives on and is used to process batch pre-authorized transactions between Financial Institutions, overseen by Payments Canada (also known as the Canadian Payments Association).

The CPA 005 file serves as a way to encode all necessary bank account and transaction details into a fixed-length, padded text file.

CPA 005 File Layout and Structure

A CPA 005 file is organized as a text file with each line exactly 1464 characters long. The file contains:

• Header and Trailer Records: The header (denoted by an A record) carries key metadata such as the file creation date, originator ID, and settlement account information. The trailer (marked with a Z record) provides summary details for reconciliation.
• D Lines (Debit) and C Lines (Credit): Each detailed record starts with a 24-character header followed by up to six segments of 240 characters each. If fewer than six segments are used, the line is padded to reach the 1464-character requirement. Although D and C lines are designed to work interchangeably, in practice debits and credits are batched separately.

Additional key points about the file layout include strict padding conventions (numeric fields are zero-left padded and text fields are space-right padded) and the handling of line breaks, which can vary across operating systems.

Key Concepts & Conventions

• Originator ID - A number issued to entities authorized to submit PAD/EFT payments.
• Bank, Transit, and Account Numbers - These three elements combine to uniquely identify bank accounts, much like a postal address.
• File Creation Number (FCN) - A sequence number that rotates from 0001 to 9999, used to prevent duplicate submissions.
• Date Format - Dates are expressed as a 6-digit number (three digits for the year and three for the day of the year).

CPA 005 Challenges

Despite the available documentation on the file specifications, generating a compliant CPA 005 file is not straightforward. The official documents - including those provided by the Canadian Payments Association - contain several inaccuracies and missing details, such as:

• Inconsistent Field Definitions: Conflicting information exists about reserved fields and the positioning of essential data like the settlement account details within the header.
• Omissions in Interface Definitions: Unlike modern APIs that specify interfaces (e.g., REST or SOAP), CPA 005 files are simple text files uploaded via an authenticated online banking interface. There’s no inherent transmission protocol defined in the standard.
• Padding and Line Break Conventions: The documentation does not clearly specify the handling of line breaks or the padding rules, leading to potential misinterpretations.