I asked Claude which marketing channel actually pays. Here's the setup.

Most founders ask their analytics "where did my visitors come from?"

The better question is "where did my paying customers come from?" And now you can ask it in plain English, inside Claude or any assistant that speaks MCP.

Here is the exact setup, step by step. It takes about 15 minutes.

What you need

1. Your analytics has to know which visit came before each payment. Visitor counts alone can't answer "which channel pays".
2. That data has to be reachable by your AI assistant. That is what MCP (Model Context Protocol) is for: a small, standard door your assistant can knock on to read data.

Step 1: give every visitor an ID

Your tracking script sets one first-party ID per visitor and remembers the first source: referrer, UTM tags or "direct".

Step 2: pass that ID into checkout

When someone clicks Buy, put the visitor ID in the checkout's metadata. On Stripe that's metadata, on Dodo Payments and Polar it's the same idea. One line where you create the checkout.

Step 3: join payments to visits

When the payment webhook arrives, look up the visitor ID and credit the payment to the channel of the visit before it. Now every dollar has a source.

Step 4: expose it over MCP

This is where it gets fun. I built this into Virling, an open-source revenue analytics tool written in Rust. It serves an MCP endpoint at /mcp with read-only tools:

• get_overview: visitors, revenue, conversion, revenue per visitor, vs the previous period
• get_breakdown: revenue per channel, referrer, campaign, landing page, country, device
• get_retention: which channel's customers keep paying
• list_payments and get_visitor_timeline: the full path of any payment

Add it to Claude Code with one command:

claude mcp add --transport http virling https://your-server/mcp \
  --header "Authorization: Bearer vk_..."

On claude.ai it's a custom connector with the same URL and header.

Step 5: ask questions

Things I ask now instead of clicking through dashboards:

• "Which channel made the most money per visitor in the last 30 days?"
• "Is AI traffic worth more than search traffic for me?"
• "Show me the path of the last 5 customers who paid."
• "Which channel's customers churn the fastest?"

On the demo site, the answer to the first one: Direct brought twice the visitors of AI, but AI visitors were worth almost 7x more each. You would never guess that from a traffic chart.

Why this matters

Traffic tells you which channel is loud. Revenue per visitor tells you which one pays. Once your assistant can see both, you stop arguing about channels and just ask.

Virling is open source and free to self-host today. The hosted version opens soon: the first 50 customers get 40% off for life. virling.com

Which channel brings you the most paying customers right now? Curious if anyone else is seeing AI traffic convert better than search.