Paypal IPN

Sample code for Paypal IPN using WebDNA.
By Dan Strong -
Free to use, no strings attached.


1) Log Into your PayPal acct.
2) Go to "Profile", and under "Selling Preferences" click "Instant Payment Notification"
3) Click "Edit Settings" button
4) Enter your "Notification URL" (doesn't need to be https) where your IPN code will live
5) Choose "IPN messages - Receive IPN messages (Enabled)" and Save.

1) When a payment is made to your PayPal account your IPN Notification URL page expects to receive a string very similar to this:

2) You must echo this string back to paypal along with an additional name/value pair "cmd=_notify-validate"
3) You can either save this string directly to a .db for later or break out the vars via [formvariables], whichever works best for you.


[/!][TCPsend skipheader=T]POST /cgi-bin/webscr HTTP/1.0[unurl]%0D%0A[/unURL][!]
[/!]USER-AGENT: Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)[unurl]%0D%0A[/unURL][!]
[/!]Content-Type: application/x-www-form-urlencoded[unurl]%0D%0A[/unURL][!]
[/!]Content-Length: [countchars][content][/countChars][unurl]%0D%0A[/unURL][!]

Your IPN Notification URL will receive a [response] from PayPal of simply VERIFIED or INVALID.
Process your data accordingly.

To prevent fraud, Paypal suggests that you
1) Check the "payment_status" is "Completed"
2) Check that "txn_id" has not been previously processed
3) Check that "receiver_email" is your Primary PayPal email
4) Check that "payment_amount"/"payment_currency" are correct
Dan Strong


Top Articles:

Tips and Tricks

A list of user-submitted tips ...

WebDNA Libraries

A list of available libraries for WebDNA...

AWS Raw WebDNA LAMP-Plus WebServer

Amazon Web Services (AWS) README for Machine Image ID...


BioType is a behavioral biometrics WebDNA function based on ADGS research and development (from version 8...

Download WebDNA Applications

WebDNA applications...

WebDNA Modules

A list of the currently available modules...

Related Readings:

Database backup

How to make a backup of your databases...

How to setup CODA to work with WebDNA?

This page will show graphically how to setup CODA as a WebDNA partner :-)...

Spaghetti code

How to get rid of very long search strings...

How to keep the text variable after a function has finished

By default...

Redefining [date] & [time] to match your time zone

Your server is not always in the same time zone as your web site...

Write Once Use Many

Reuse the same code over and over again on your site with the [include] context...