diff --git a/app/api/affiliate/join/route.ts b/app/api/affiliate/join/route.ts
new file mode 100644
index 0000000..6a11fc1
--- /dev/null
+++ b/app/api/affiliate/join/route.ts
@@ -0,0 +1,42 @@
+import { NextRequest, NextResponse } from "next/server";
+import { findOrCreateAccountByEmail, enrollAffiliate } from "@/lib/db";
+import { safeDomain } from "@/lib/config";
+
+export const runtime = "nodejs";
+export const dynamic = "force-dynamic";
+
+const EMAIL_RE = /^[^\s@]+@[^\s@]+\.[^\s@]{2,}$/;
+
+function baseUrl(): string {
+  return (process.env.APP_BASE_URL || "https://moshcoding.com").replace(/\/+$/, "");
+}
+
+/**
+ * Public affiliate signup for a specific domain. Email-only — no session needed.
+ * Creates a passwordless account (claimable later from the dashboard) and enrolls
+ * it as an 80% affiliate, then hands back a domain-targeted referral link. That
+ * link drops the 90-day first-touch `mc_ref` cookie (see middleware) so waitlist
+ * signups on <dn> are credited to the affiliate.
+ */
+export async function POST(req: NextRequest) {
+  let body: any = {};
+  try { body = await req.json(); } catch { /* empty */ }
+
+  const email = String(body?.email || "").trim().toLowerCase();
+  const dn = safeDomain(body?.dn);
+  if (!EMAIL_RE.test(email)) return NextResponse.json({ error: "Enter a valid email." }, { status: 400 });
+  if (!dn) return NextResponse.json({ error: "Missing domain." }, { status: 400 });
+
+  const account = await findOrCreateAccountByEmail(email);
+  const aff = await enrollAffiliate(account.id);
+
+  return NextResponse.json({
+    ok: true,
+    dn,
+    code: aff.code,
+    commission_pct: aff.commission_pct,
+    // Domain-scoped share link: lands on <dn>'s page and sets the 90-day cookie.
+    shareUrl: `${baseUrl()}/?dn=${encodeURIComponent(dn)}&ref=${encodeURIComponent(aff.code)}`,
+    manageUrl: `${baseUrl()}/dashboard`,
+  });
+}
diff --git a/app/globals.css b/app/globals.css
index ccd18f9..7431872 100644
--- a/app/globals.css
+++ b/app/globals.css
@@ -245,6 +245,20 @@ h2 { font-family: var(--display); font-weight: 400; text-transform: uppercase; f
 .t-bid { display: inline-block; margin: 26px auto 0; font-family: var(--mono); font-size: 13px; letter-spacing: 0.06em;
   color: var(--tenant-accent, var(--acid)); border: 1px solid var(--line); border-radius: 999px; padding: 9px 16px; transition: background .15s, color .15s; }
 .t-bid:hover { background: var(--tenant-accent, var(--acid)); color: #0a0c08; }
+
+/* tenant affiliate join */
+.t-aff { margin: 44px auto 0; max-width: 520px; padding: 22px 20px; border: 1px solid var(--line); border-radius: 14px; background: var(--panel, #101210); }
+.t-aff-h { font-family: var(--display); font-weight: 400; text-transform: uppercase; font-size: clamp(22px, 4vw, 32px); line-height: 1; margin: 0 0 10px; color: var(--tenant-accent, var(--acid)); }
+.t-aff-sub { font-family: var(--mono); font-size: 12.5px; line-height: 1.6; color: var(--ash); margin: 0 0 16px; }
+.t-aff-sub b { color: var(--bone); }
+.t-aff-sub a { color: var(--tenant-accent, var(--acid)); text-decoration: underline; }
+.t-aff-out { text-align: left; }
+.t-aff-label { font-family: var(--mono); font-size: 11px; letter-spacing: 0.08em; text-transform: uppercase; color: var(--ash); margin: 0 0 8px; }
+.t-aff-row { display: flex; gap: 10px; flex-wrap: wrap; }
+.t-aff-link { flex: 1 1 240px; font-family: var(--mono); font-size: 13px; color: var(--bone); background: #0b0d0a; border: 1px solid var(--line); border-radius: 8px; padding: 11px 12px; }
+.t-aff-link:focus { border-color: var(--tenant-accent, var(--acid)); outline: none; }
+.t-aff .wform { margin: 0; }
+.t-aff .fmsg { text-align: center; }
 .bid-stats { display: flex; flex-wrap: wrap; justify-content: center; gap: 14px; margin: 20px auto; max-width: 460px; }
 .bid-stats > div { flex: 1 1 120px; background: var(--panel, #101210); border: 1px solid var(--line); border-radius: 8px; padding: 12px 14px; }
 .bid-stats dt { font-family: var(--mono); font-size: 10px; letter-spacing: 0.08em; text-transform: uppercase; color: var(--ash); margin: 0 0 4px; }
diff --git a/components/AffiliateJoin.tsx b/components/AffiliateJoin.tsx
new file mode 100644
index 0000000..f02129f
--- /dev/null
+++ b/components/AffiliateJoin.tsx
@@ -0,0 +1,87 @@
+"use client";
+import { useState } from "react";
+import { copyText } from "@/lib/clipboard";
+
+/**
+ * Public "become an affiliate for this domain" widget shown on a tenant page.
+ * Email-only signup → returns a domain-scoped referral link (80% free, 90-day
+ * cookie). Mirrors WaitlistForm's UX.
+ */
+export default function AffiliateJoin({ dn }: { dn: string }) {
+  const [email, setEmail] = useState("");
+  const [busy, setBusy] = useState(false);
+  const [msg, setMsg] = useState<{ text: string; ok: boolean } | null>(null);
+  const [result, setResult] = useState<{ shareUrl: string; commission_pct: number } | null>(null);
+
+  async function submit(e: React.FormEvent) {
+    e.preventDefault();
+    setMsg(null);
+    if (!/^[^\s@]+@[^\s@]+\.[^\s@]{2,}$/.test(email.trim())) {
+      setMsg({ text: "That doesn't look like an email.", ok: false });
+      return;
+    }
+    setBusy(true);
+    try {
+      const res = await fetch("/api/affiliate/join", {
+        method: "POST",
+        headers: { "content-type": "application/json" },
+        body: JSON.stringify({ email: email.trim(), dn }),
+      });
+      const data = await res.json();
+      if (!res.ok) throw new Error(data.error || "Something broke.");
+      setResult({ shareUrl: data.shareUrl, commission_pct: data.commission_pct });
+      setMsg({ text: `You're an affiliate for ${dn}. 🤘`, ok: true });
+      setEmail("");
+    } catch (err: any) {
+      setMsg({ text: err.message || "Network died. Try again.", ok: false });
+    } finally {
+      setBusy(false);
+    }
+  }
+
+  const copy = () => {
+    if (!result) return;
+    copyText(result.shareUrl).then((ok) =>
+      setMsg({ text: ok ? "Link copied. 🤘" : "Couldn't copy — select the link and copy it.", ok }),
+    );
+  };
+
+  const pct = result?.commission_pct ?? 80;
+  return (
+    <section className="t-aff" aria-label="Affiliate program">
+      <h2 className="t-aff-h">Promote {dn} — earn {pct}%</h2>
+      <p className="t-aff-sub">
+        Join free, grab your link, and earn <b>{pct}% commission</b> on fees from everyone you refer.
+        <b> 90-day cookie</b> — you get credited if they convert within 90 days.
+      </p>
+
+      {!result ? (
+        <form className="wform" onSubmit={submit} noValidate>
+          <input
+            type="email" name="email" placeholder="you@dev.null" required autoComplete="email"
+            value={email} onChange={(e) => setEmail(e.target.value)}
+          />
+          <button type="submit" className="btn btn-acid" disabled={busy}>
+            {busy ? "Summoning…" : "Become an affiliate"}
+          </button>
+        </form>
+      ) : (
+        <div className="t-aff-out">
+          <p className="t-aff-label">Your referral link for {dn}:</p>
+          <div className="t-aff-row">
+            <input
+              className="t-aff-link" readOnly value={result.shareUrl}
+              onFocus={(e) => e.currentTarget.select()}
+            />
+            <button type="button" className="btn btn-ghost" onClick={copy}>Copy</button>
+          </div>
+          <p className="t-aff-sub">Share it anywhere. Add a payout wallet in your <a href="/dashboard">dashboard</a> to get paid.</p>
+        </div>
+      )}
+
+      <p className={`fmsg${msg ? (msg.ok ? " ok" : " err") : ""}`} role="status" aria-live="polite">
+        {msg?.text ?? ""}
+      </p>
+    </section>
+  );
+}
diff --git a/components/Tenant.tsx b/components/Tenant.tsx
index d8ba0bf..15dc300 100644
--- a/components/Tenant.tsx
+++ b/components/Tenant.tsx
@@ -1,5 +1,6 @@
 import type { TenantConfig } from "@/lib/config";
 import WaitlistForm from "./WaitlistForm";
+import AffiliateJoin from "./AffiliateJoin";
 import SharePost from "./SharePost";
 import LinkIcon, { kindFromUrl } from "./LinkIcon";
 import CrawlProofAd from "./CrawlProofAd";
@@ -105,6 +106,8 @@ export default function Tenant({ cfg }: { cfg: TenantConfig }) {
           </div>
         )}
 
+        <AffiliateJoin dn={cfg.dn} />
+
         <a className="t-bid" href={`/?bid=${encodeURIComponent(cfg.dn)}`}>💰 Bid on this domain</a>
 
         {cfg.adSlot && <CrawlProofAd slot={cfg.adSlot} format={cfg.adFormat} />}