diff --git a/app/main.py b/app/main.py
index 69b4602..f9e651a 100644
--- a/app/main.py
+++ b/app/main.py
@@ -142,13 +142,73 @@ SMTP_USERNAME = os.environ.get("CLOUDRON_MAIL_SMTP_USERNAME", "")
 SMTP_PASSWORD = os.environ.get("CLOUDRON_MAIL_SMTP_PASSWORD", "")
 MAIL_FROM = os.environ.get("CLOUDRON_MAIL_FROM", "info@inference.coop")
 MAIL_FROM_NAME = os.environ.get("CLOUDRON_MAIL_FROM_DISPLAY_NAME", "Inference Cooperative")
-# Reply-to address. The sendmail addon only authorizes sending from the app's
-# own address (portal.app@inference.coop), so the From header is pinned there;
-# we set Reply-To so member replies land at the co-op inbox instead.
+# Reply-to address so member replies land at the co-op inbox.
 MAIL_REPLY_TO = os.environ.get("MAIL_REPLY_TO", "info@inference.coop")
 # Public base URL for the portal (used in email links).
 PORTAL_BASE = os.environ.get("PORTAL_BASE", "https://portal.inference.coop")
 
+# Listmonk newsletter integration. The portal keeps the "Members" list in sync:
+# subscribe on provision, unsubscribe on deactivation. Auth uses listmonk's
+# native API-user token scheme (Authorization: token <user>:<token>).
+LISTMONK_BASE = os.environ.get("LISTMONK_BASE", "https://newsletter.inference.coop")
+LISTMONK_API_USER = os.environ.get("LISTMONK_API_USER", "portal-sync")
+LISTMONK_API_TOKEN = os.environ.get("LISTMONK_API_TOKEN", "")
+LISTMONK_LIST_ID = int(os.environ.get("LISTMONK_LIST_ID", "3"))  # "Members" list
+
+
+async def listmonk_sync(email: str, subscribe: bool) -> None:
+    """Subscribe or unsubscribe a member to the newsletter list.
+
+    Best-effort: never raises, so a newsletter outage can't break provisioning.
+    """
+    if not LISTMONK_API_TOKEN:
+        logger.warning("Listmonk not configured; skipping sync for %s", email)
+        return
+    auth = {"Authorization": f"token {LISTMONK_API_USER}:{LISTMONK_API_TOKEN}"}
+    try:
+        async with httpx.AsyncClient(timeout=10.0) as client:
+            if subscribe:
+                r = await client.post(
+                    f"{LISTMONK_BASE}/api/subscribers",
+                    headers=auth,
+                    json={
+                        "email": email,
+                        "name": "",
+                        "status": "enabled",
+                        "lists": [LISTMONK_LIST_ID],
+                        "preconfirm_subscriptions": True,
+                    },
+                )
+            else:
+                # Look up the subscriber id by email, then blocklist by id.
+                # (listmonk's blocklist endpoint takes an id, not an email.)
+                q = await client.get(
+                    f"{LISTMONK_BASE}/api/subscribers",
+                    headers=auth,
+                    params={"query": f"subscribers.email='{email}'"},
+                )
+                if q.status_code != 200:
+                    logger.warning("Listmonk lookup for %s failed: %s", email, q.status_code)
+                    return
+                results = q.json().get("data", {}).get("results", [])
+                if not results:
+                    return  # not subscribed; nothing to do
+                sid = results[0]["id"]
+                r = await client.put(
+                    f"{LISTMONK_BASE}/api/subscribers/{sid}/blocklist",
+                    headers=auth,
+                )
+            if r.status_code not in (200, 201):
+                logger.warning(
+                    "Listmonk sync %s for %s failed: %s",
+                    "subscribe" if subscribe else "unsubscribe",
+                    email,
+                    r.status_code,
+                )
+    except Exception as e:
+        logger.warning("Listmonk sync error for %s: %s", email, e)
+
+
 
 def _verify_portal_secret(request: Request) -> None:
     """Reject requests that didn't come through LibreChat (shared secret)."""
@@ -608,6 +668,9 @@ async def provision_member(email: str, name: str, slug: str = "") -> str:
     subject, text, html = welcome_email(name, setup_url)
     send_email(email, subject, text, html)
 
+    # Subscribe to the member newsletter (single opt-in; members consented by joining).
+    await listmonk_sync(email, subscribe=True)
+
     await sync_loomio_memberships()
     logger.info("Provisioned member %s (user_id=%s)", email, user_id)
     return user_id
@@ -868,6 +931,7 @@ async def opencollective_webhook(request: Request, token: str):
                     await cloudron_set_group(member["cloudron_user_id"], INACTIVE_GROUP_ID)
                 # Mark inactive in our DB (key injector will refuse requests)
                 deactivate_member(member["email"])
+                await listmonk_sync(member["email"], subscribe=False)
                 await sync_loomio_memberships()
                 logger.info("Deactivated member %s (slug=%s)", member["email"], slug)
                 return JSONResponse({"status": "deactivated", "email": member["email"]})
@@ -1364,6 +1428,7 @@ async def reconcile_memberships() -> dict:
                 if INACTIVE_GROUP_ID and user_id:
                     await cloudron_set_group(user_id, INACTIVE_GROUP_ID)
                 deactivate_member(email)
+                await listmonk_sync(email, subscribe=False)
                 deactivated_count += 1
                 logger.info("Sweep: deactivated %s", email)
             except Exception as e: