See which traffic sources bring your Lemon Squeezy sales

Checkout links

A small script in the browser

The SuprAnalytics script doesn't change Lemon Squeezy links on its own. Add this snippet after it: when a visitor clicks a link to .lemonsqueezy.com/checkout, it sets checkout[custom][supr_visitor_id] on the link.

<script>
  document.addEventListener("click", function (e) {
    var link = e.target.closest && e.target.closest('a[href*=".lemonsqueezy.com/checkout"]');
    if (!link || !window.supr || !window.supr.visitorId) return;
    var url = new URL(link.href);
    url.searchParams.set("checkout[custom][supr_visitor_id]", window.supr.visitorId());
    link.href = url.toString();
  }, true);
</script>

Browser-side code from the guide, with no keys in it. It sets the id at the click, so links added later are covered too. Optionally, checkout[custom][supr_session_id] from window.supr.sessionId() credits the order to that exact visit.

Checkout links, in the guide

Checkouts created with the API

On your server

When your server creates a checkout through Lemon Squeezy's API, read the supr_visitor_id cookie from the visitor's request and put it in checkout_data.custom.supr_visitor_id. Your API key stays on the server.

• The same custom-data keys as links: supr_visitor_id, and optionally supr_session_id
• Nothing to change on your products or prices in Lemon Squeezy: the id rides on each checkout

Checkouts with the API, in the guide