Wednesday, May 17, 2006

Connecting to Authorize.net with PHP

By Justin Silverton

What is authorize.net?

The Authorize.Net Payment Gateway is a secure Internet bridge between merchant businesses and the credit card and electronic check payment processing networks. We provide merchants with fast, reliable and secure passage for transaction data via a 128-bit Secure Sockets Layer (SSL) Internet Protocol (IP) connection, and manage the complex routing of payment information to the appropriate credit card processors. See a diagram that illustrates a typical Authorize.Net credit card transaction.

The Authorize.Net Payment Gateway is available to merchants seven days a week, 24 hours a day. The payment gateway offers many features and options that can be tailored to specific merchant business models.

Where do I start?

The first thing that you need to do, is signup with a test account. This will allow you to test out transactions to make sure your scripts are interfacing properly with their API. Here is the URL for getting your account:


API documentation can also be found here:


after signing up, you should receive your new account info within 48 hours.

The Code

I have a library available here: (URL). It is originally written by Micah Carrick and is under the GPL/GNU public license. I have made some important additions to the main library, which are needed for it to function properly.

you can get it here: http://www.electronicfiles.net/files/1773/authorize_lib.zip

Requirements: PHP version 4 and above with the CURL extensions enabled

The following 3 files are contained in the above .zip download:

authorizenet.class.php - main class library for connecting to the authorize.net gateway
demo.php - an example driver file that shows how to use the library file. A test transaction is made to the main gateway.
ca-bundle.crt - main certificate file required by CURL for SSL transactions (windows users can place this in c:\windows\system32)

Important Variables that you need to change

Location: authorizenet.class.php

curl_setopt ($ch, CURLOPT_CAINFO,"c:\\windows\\system32\\ca-bundle.crt");
curl_setopt ($ch,CURLOPT_CAPATH,"c:\\windows\\system32\\ca-bundle.crt");

change the 3rd parameter "c:\\windows\\system32\\ca-bundle.crt" to the location of your CRT file.

Location: authorizenet.class.php

var $gateway_url = "https://test.authorize.net/gateway/transact.dll";

it currently points to the authorize.net gateway for test accounts. If you have an account that is performing real transactions, change this variable to the following value: ""https://secure.authorize.net/gateway/transact.dll"

Location: demo.php

$a->add_field('x_login', 'YOUR_USERID');
$a->add_field('x_password', 'YOUR_PASSWORD');

change x_login to your Login ID (not partner ID)
and x_password to your password

You should have received both of these in an email from authorize.net


  • PEAR's Payment_Process package provides a consistent API for processing online transactions. There is a driver for Authorize.net. Using this package would allow you to build your application in a more generic way and allow you to change payment gateways if needed.

    By Anonymous Scott Mattocks, at 7:28 AM  

  • I have tried this PEAR module a couple of weeks ago and it still has a lot of bugs that need to be fixed. This is why I decided to use another library.

    By Blogger justin silverton, at 3:44 PM  

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