Most affiliate sites use two networks: Amazon and one other. The single most under-built piece of any affiliate setup is the link tracking layer that lets you swap programs without rewriting content. Here is the pattern I use.
The problem
You start with Amazon. Add ClickBank six months later. Add Rakuten a year after that. Now every link in your content references one of three networks. When a network changes its URL format, raises commissions, or shuts down, you have to find and update every link on the site.
The amateur solution: search and replace. The professional solution: a link layer that abstracts the network away from the content.
The link layer pattern
Step 1: Define a redirect endpoint per product
Every product you recommend has its own URL on your site: /go/product-name/. That URL is a 302 redirect to the current affiliate URL for that product on the current network.
Step 2: Store the network and product ID separately
In a database or config file: product-name → network=amazon, network_id=B08N5WR9W1. The URL /go/product-name/ looks up the network, calls the right URL builder, and redirects.
Step 3: Update network mappings centrally
When Amazon changes its URL format, you update one PHP function. When you want to swap from Amazon to Walmart, you change the network field for that product in the config. Every link on the site now points to the new network.
What this gets you
A/B testing networks
Run half your traffic to Amazon, half to Walmart, measure conversion. The link layer makes this a config change.
Sunset protection
When a network shuts down (this happens more than people think), you swap to a replacement in hours, not weeks.
Commission optimization
When one network raises commissions, you can route more links there without touching content.
Implementation options
Plugin-based
Pretty Links or ThirstyAffiliates on WordPress. Both handle the link layer natively. For most affiliate sites, this is the right answer.
Custom PHP
For sites with complex routing logic or custom network integrations. More work but more flexibility.
Cloud-based
Services like LinkTrust or Linkfire. More expensive, but built for high-volume affiliate operations.
The minimum viable setup
If you do nothing else, do this: every affiliate link on your site is a redirect through a single endpoint. The endpoint maps to the network. The mapping is in one file. You can update the mapping in 30 seconds without finding links in your content.
That single change saves you 20-40 hours of work over the next two years, minimum.