Find which channel brings paying customers

Visitor counts tell you which channel is loud. This guide sets Virling up so every payment shows the channel that brought it, then shows how to read the numbers and act on them each week. With a server that already runs Docker it takes about 15 minutes.

It works with Stripe, Dodo Payments and Polar. LemonSqueezy payments import and count toward revenue, but linking them to visits is Not available yet.

What you need

• A Linux or macOS server with Docker, or one of the release binaries, and a domain such as stats.example.com pointing at it.
• Your site, where you can add one tag to the <head>.
• A payment account on Stripe, Dodo Payments or Polar.

1. Start Virling and add your site

docker run -d --name virling \
  -p 8080:8080 \
  -v virling-data:/data \
  -e VIRLING_BASE_URL=https://stats.example.com \
  ghcr.io/virling/virling:latest serve --app

docker exec virling virling add-site yourdomain.com --owner you@example.com

Put HTTPS in front of it with your usual reverse proxy, then sign in at https://stats.example.com/login. Without SMTP, the sign-in link is printed to docker logs virling.

2. Add the script

Paste this before </head> on every page:

<script defer src="https://stats.example.com/v.js"
  data-site="yourdomain.com"></script>

It is about 1.2 KB gzipped and sets one first-party cookie, virling_vid, which is the visitor ID that checkout will carry. Do not turn on cookieless mode for this site: without the visitor ID, payments cannot be linked to visits.

Tag the links you share with UTM parameters, or use tracked links, so each post and campaign shows up by name.

3. Connect payments with a read-only key

In the app, open your site, then Setup, then Connect payments, and paste the key:

Virling imports the last 90 days, then checks for new payments every minute. It never creates, changes or refunds anything.

4. Pass the visitor ID into checkout

This is the step that turns traffic numbers into revenue numbers.

• Payment links need nothing. Stripe Payment Links, Polar checkout links (with a virling_vid custom field) and Dodo Payments links are tagged by the script on click.
• Checkout you create on your server needs one line. For Stripe Checkout:

const session = await stripe.checkout.sessions.create({
  client_reference_id: req.cookies.virling_vid,
  line_items: [{ price: "price_...", quantity: 1 }],
  mode: "subscription",
  success_url: "https://yourdomain.com/thanks",
});

For Dodo Payments and Polar, set metadata.virling_vid the same way. See Link checkout to visits for each provider.

Check it: make a test payment from a page that runs the script, wait a minute, and open the payments list. The payment should show a channel instead of Unattributed.

5. Read which channel pays

Open the dashboard and look at the Channels card with revenue next to visitors.

• Per visitor is the number to compare. It is revenue divided by visitors for that channel, so a small channel that pays well stands out from a big one that doesn’t.
• Payments lists every payment with its channel. Open one to see its journey: the sessions before it and which one got the credit.
• Referrers and campaigns break a channel down to the post, site or UTM campaign that brought the money.

By default a payment is credited to the latest visit in the last 90 days that was not Direct. Someone who found you on a forum and came back a week later by typing your URL is credited to the forum. To see which channels introduce buyers instead, switch to first touch. See Model and lookback window.

6. The weekly five-minute check

Once a week, with at least a few weeks of data:

1. Sort channels by revenue, then look at per visitor.
2. Find the channel with lots of visitors and little revenue. That is where effort goes without paying back.
3. Find the channel with few visitors and high per-visitor revenue. That is where more effort is most likely to pay.
4. Open the last few payments and read their journeys, to see what paying customers did before they paid.
5. Change one thing, and compare next week.

Renewals keep the channel of the customer’s first payment, so a channel keeps its credit for the subscribers it brought. Retention by channel shows which channels bring customers who stay.

When numbers look wrong

• Most revenue is Unattributed. Checkout is not carrying the visitor ID. See Unattributed revenue.
• A channel is missing. Check how the visit was classified in Channels, and add UTM tags to links you control.
• Old payments have no channel. Payments are backfilled 90 days, but visits only exist from when the script was added.