Referral quickstart: Express

Referrals in an Express app: the tag in your templates, the partner's code kept by your own server, every signup reported as a lead, and sales from your billing system.

Before you start

• A key with the Referral tracking preset (the single scope conversions:write), made under Settings, Developers. Keep it on your server as BOLTCLAW_API_KEY, never in a browser or an app.
• The program's id, on its Setup tab, as BOLTCLAW_PROGRAM_ID.

1. Put the tag on your site

Add the version 2 tag to every page, in your root layout or template. It keeps a partner's code from ?via=<code> in a first-party cookie on your own domain, bc_ref, for the program's cookie window, and gives you BoltClawReferral.code() in the browser.

<script src="https://boltclaw.ai/referrals/v2.js" defer data-payment-links="auto"></script>

data-payment-links="auto" is only for Stripe Payment Links and the Buy Button; data-welcome="auto" adds the friend's welcome. The tag makes no request at all unless the welcome is on and the visitor arrived with a code.

2. Keep the code from your server

A middleware sets bc_ref from ?via= in your own response, and optionally reports the visit as a click for partner links that open straight on your site (a click through boltclaw.ai/r/<code> is already counted). A click earns nothing by itself.

// referral-cookie.js
const CODE = /^[a-z0-9]+(-[a-z0-9]+)*$/;
const COOKIE_DAYS = 30; // the program's cookie window (30 days unless you changed it)

export function keepReferral(req, res, next) {
  const code = typeof req.query.via === "string" ? req.query.via : null;
  if (code && code.length >= 3 && code.length <= 40 && CODE.test(code)) {
    res.cookie("bc_ref", code, { path: "/", maxAge: COOKIE_DAYS * 86400 * 1000, sameSite: "lax", secure: true, httpOnly: false });
    fetch("https://api.boltclaw.ai/v1/referrals/clicks", {
      method: "POST",
      headers: { Authorization: `Bearer ${process.env.BOLTCLAW_API_KEY}`, "Content-Type": "application/json" },
      body: JSON.stringify({ code, ip: req.ip, user_agent: req.get("user-agent"), referrer: req.get("referer"), landing_path: req.path }),
    }).catch(() => undefined);
  }
  next();
}

// app.js
// app.set("trust proxy", true); // behind a proxy, so req.ip is the visitor's
// app.use(cookieParser());
// app.use(keepReferral);

Why set the cookie from your server. Safari deletes a cookie a script created once the visitor has gone 7 days of browsing without using your site, and keeps one only 24 hours on a page reached through a tracking link, so a code the tag keeps can be gone a week later. A cookie your OWN server sets in its response keeps its full lifetime, unless it comes through somebody else's host (a third-party CNAME or IP address), which Safari caps at 7 days (WebKit's published tracking prevention rules, read 2026-10-23). Setting bc_ref from your server, not HttpOnly, keeps the full window and the tag still reads it. The @boltclaw/referrals package ships the same as referralsMiddleware().

3. Report each signup as a lead

In the route that creates an account, report it with your own id for the person and the code from the cookie. event_id is the idempotency key.

// referrals.js: server only
export async function reportConversion(body) {
  const res = await fetch("https://api.boltclaw.ai/v1/referrals/conversions", {
    method: "POST",
    headers: {
      Authorization: `Bearer ${process.env.BOLTCLAW_API_KEY}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({ program_id: process.env.BOLTCLAW_PROGRAM_ID, ...body }),
  });
  if (!res.ok) throw new Error(`Bolt Claw answered ${res.status}`);
  return res.json();
}

app.post("/signup", async (req, res) => {
  const user = await createUser(req.body); // your own code
  await reportConversion({
    event: "lead",
    event_id: `signup-${user.id}`,
    customer: { id: user.id },
    referral: req.cookies.bc_ref ? { code: req.cookies.bc_ref } : undefined,
  });
  res.redirect("/welcome");
});

4. Record sales

Connect the billing system you take payments with on the Setup tab (see Connect your billing system), and pass the code to checkout as its guide shows: sales, renewals and refunds are then reported for you, and the setup status ticks them off. Not on one of the twelve? Report each sale from your server with event: "sale", your own event_id for the payment, the same customer.id as the signup, amount in minor units and currency.

5. Send a test sale

Press Send a test sale on the Setup tab: a click, a signup, a sale with two items and a partial refund go through your real rules as test data, credited to the program's test partner, never paid and never counted. To check your own wiring, send one of your own conversions with "test": true: it is test data too, and Clear test data deletes it all. The setup status's rows turn green only for live events.