If you want to offer a data feed - rss feed for your affiliates, you can use the site replication feature for this purpose. How to activate and configure the site replication feature is described here. After you did all of the steps from the previous guide, you can continue.
Your rss feed looks like this (example):
The code of the example rss feed:
Replicate your rss feed
Follow this guide and upload the rss file into the Replicated site folder, then open/edit the rss feed file and add some variables from the list. All of your affiliates will have access to this replicated rss.
Copy&paste only the variable with { } brackets.
Now our replicated rss feed with proper affiliate links looks like this:
After inserting the variables, the links will be pointing to the same destination, but with additional affiliate data. Each of your affiliates can use it with his own affiliate data.
And for different affiliate looks like this:
Now every affiliate can use your data feed as his replicated site.