diff --git a/bp/auth/routes.py b/bp/auth/routes.py
index 4d85aa7..94afc82 100644
--- a/bp/auth/routes.py
+++ b/bp/auth/routes.py
@@ -1,7 +1,7 @@
 """Authentication routes for the account app.
 
 Account is the OAuth authorization server. Owns magic link login/logout,
-OAuth2 authorize endpoint, and SSO logout.
+OAuth2 authorize endpoint, grant verification, and SSO logout.
 """
 from __future__ import annotations
 
@@ -17,13 +17,15 @@ from quart import (
     session as qsession,
     g,
     current_app,
+    jsonify,
 )
-from sqlalchemy import select
+from sqlalchemy import select, update
 from sqlalchemy.exc import SQLAlchemyError
 
 from shared.db.session import get_session
 from shared.models import User
 from shared.models.oauth_code import OAuthCode
+from shared.models.oauth_grant import OAuthGrant
 from shared.infrastructure.urls import account_url, app_url
 from shared.infrastructure.cart_identity import current_cart_identity
 from shared.events import emit_activity
@@ -39,6 +41,7 @@ from .services import (
 )
 
 SESSION_USER_KEY = "uid"
+ACCOUNT_SESSION_KEY = "account_sid"
 
 ALLOWED_CLIENTS = {"blog", "market", "cart", "events", "federation"}
 
@@ -64,30 +67,61 @@ def register(url_prefix="/auth"):
 
         # Not logged in — bounce to magic link login, then back here
         if not g.get("user"):
-            # Preserve the full authorize URL so we return here after login
-            authorize_path = request.full_path  # includes query string
+            authorize_path = request.full_path
             store_login_redirect_target()
             return redirect(url_for("auth.login_form", next=authorize_path))
 
-        # Logged in — issue authorization code
+        # Logged in — create grant + authorization code
+        account_sid = qsession.get(ACCOUNT_SESSION_KEY)
+        if not account_sid:
+            account_sid = secrets.token_urlsafe(32)
+            qsession[ACCOUNT_SESSION_KEY] = account_sid
+
+        grant_token = secrets.token_urlsafe(48)
         code = secrets.token_urlsafe(48)
         now = datetime.now(timezone.utc)
         expires = now + timedelta(minutes=5)
 
         async with get_session() as s:
             async with s.begin():
+                grant = OAuthGrant(
+                    token=grant_token,
+                    user_id=g.user.id,
+                    client_id=client_id,
+                    issuer_session=account_sid,
+                )
+                s.add(grant)
+
                 oauth_code = OAuthCode(
                     code=code,
                     user_id=g.user.id,
                     client_id=client_id,
                     redirect_uri=redirect_uri,
                     expires_at=expires,
+                    grant_token=grant_token,
                 )
                 s.add(oauth_code)
 
         sep = "&" if "?" in redirect_uri else "?"
         return redirect(f"{redirect_uri}{sep}code={code}&state={state}")
 
+    # --- Grant verification (internal endpoint) ------------------------------
+
+    @auth_bp.get("/internal/verify-grant")
+    async def verify_grant():
+        """Called by client apps to check if a grant is still valid."""
+        token = request.args.get("token", "")
+        if not token:
+            return jsonify({"valid": False}), 200
+
+        async with get_session() as s:
+            grant = await s.scalar(
+                select(OAuthGrant).where(OAuthGrant.token == token)
+            )
+            if not grant or grant.revoked_at is not None:
+                return jsonify({"valid": False}), 200
+            return jsonify({"valid": True}), 200
+
     # --- Magic link login flow -----------------------------------------------
 
     @auth_bp.get("/login/")
@@ -97,7 +131,6 @@ def register(url_prefix="/auth"):
         if cross_cart_sid:
             qsession["cart_sid"] = cross_cart_sid
         if g.get("user"):
-            # If there's a pending redirect (e.g. OAuth authorize), follow it
             redirect_url = pop_login_redirect_target()
             return redirect(redirect_url)
         return await render_template("auth/login.html")
@@ -194,14 +227,55 @@ def register(url_prefix="/auth"):
             )
 
         qsession[SESSION_USER_KEY] = user_id
+        # Fresh account session ID for grant tracking
+        qsession[ACCOUNT_SESSION_KEY] = secrets.token_urlsafe(32)
 
         redirect_url = pop_login_redirect_target()
         return redirect(redirect_url, 303)
 
     @auth_bp.post("/logout/")
     async def logout():
+        # Revoke all grants issued by this account session
+        account_sid = qsession.get(ACCOUNT_SESSION_KEY)
+        if account_sid:
+            try:
+                async with get_session() as s:
+                    async with s.begin():
+                        await s.execute(
+                            update(OAuthGrant)
+                            .where(OAuthGrant.issuer_session == account_sid)
+                            .where(OAuthGrant.revoked_at.is_(None))
+                            .values(revoked_at=datetime.now(timezone.utc))
+                        )
+            except SQLAlchemyError:
+                current_app.logger.exception("[auth] failed to revoke grants")
+
         qsession.pop(SESSION_USER_KEY, None)
-        return redirect(url_for("auth.sso_logout"))
+        qsession.pop(ACCOUNT_SESSION_KEY, None)
+        from shared.infrastructure.urls import blog_url
+        return redirect(blog_url("/"))
+
+    @auth_bp.get("/sso-logout/")
+    async def sso_logout():
+        """SSO logout called by client apps: revoke grants, clear session."""
+        account_sid = qsession.get(ACCOUNT_SESSION_KEY)
+        if account_sid:
+            try:
+                async with get_session() as s:
+                    async with s.begin():
+                        await s.execute(
+                            update(OAuthGrant)
+                            .where(OAuthGrant.issuer_session == account_sid)
+                            .where(OAuthGrant.revoked_at.is_(None))
+                            .values(revoked_at=datetime.now(timezone.utc))
+                        )
+            except SQLAlchemyError:
+                current_app.logger.exception("[auth] failed to revoke grants")
+
+        qsession.pop(SESSION_USER_KEY, None)
+        qsession.pop(ACCOUNT_SESSION_KEY, None)
+        from shared.infrastructure.urls import blog_url
+        return redirect(blog_url("/"))
 
     @auth_bp.get("/clear/")
     async def clear():
@@ -211,27 +285,4 @@ def register(url_prefix="/auth"):
         resp.delete_cookie("blog_session", domain=".rose-ash.com", path="/")
         return resp
 
-    @auth_bp.get("/sso-logout/")
-    async def sso_logout():
-        """SSO logout: clear account session, then render a page with hidden
-        iframes that clear each client app's first-party session cookie.
-        Tolerates dead apps — iframes that fail are silently ignored."""
-        qsession.pop(SESSION_USER_KEY, None)
-
-        from shared.infrastructure.urls import blog_url, market_url, cart_url, events_url, federation_url
-
-        clear_urls = [
-            blog_url("/auth/sso-clear"),
-            market_url("/auth/sso-clear"),
-            cart_url("/auth/sso-clear"),
-            events_url("/auth/sso-clear"),
-            federation_url("/auth/sso-clear"),
-        ]
-
-        return await render_template(
-            "auth/signing_out.html",
-            clear_urls=clear_urls,
-            final_url=blog_url("/"),
-        )
-
     return auth_bp
diff --git a/shared b/shared
index 9a637c6..6bb2652 160000
--- a/shared
+++ b/shared
@@ -1 +1 @@
-Subproject commit 9a637c6227e5238ea9539801f9f7d01e97b53872
+Subproject commit 6bb26522a127e171045b8b2cca6e4710046ccec5
diff --git a/templates/auth/signing_out.html b/templates/auth/signing_out.html
deleted file mode 100644
index dc22e6e..0000000
--- a/templates/auth/signing_out.html
+++ /dev/null
@@ -1,21 +0,0 @@
-{% extends "_types/root/_index.html" %}
-{% block meta %}{% endblock %}
-{% block title %}Signing out — Rose Ash{% endblock %}
-{% block content %}
-<div class="py-8 max-w-md mx-auto text-center">
-  <h1 class="text-2xl font-bold mb-4">Signing out&hellip;</h1>
-  <p class="text-stone-500 text-sm">You will be redirected shortly.</p>
-</div>
-
-{# Fire-and-forget: clear each client app's session via hidden iframes #}
-{% for url in clear_urls %}
-<iframe src="{{ url }}" style="display:none" aria-hidden="true"></iframe>
-{% endfor %}
-
-<script>
-  // Give iframes a moment to load, then redirect
-  setTimeout(function() {
-    window.location.href = "{{ final_url }}";
-  }, 1500);
-</script>
-{% endblock %}