diff --git a/alembic/versions/p6n4k0l2m3_add_oauth_codes_table.py b/alembic/versions/p6n4k0l2m3_add_oauth_codes_table.py
new file mode 100644
index 0000000..d74a687
--- /dev/null
+++ b/alembic/versions/p6n4k0l2m3_add_oauth_codes_table.py
@@ -0,0 +1,37 @@
+"""Add oauth_codes table
+
+Revision ID: p6n4k0l2m3
+Revises: o5m3j9k1l2
+Create Date: 2026-02-23
+"""
+from alembic import op
+import sqlalchemy as sa
+
+revision = "p6n4k0l2m3"
+down_revision = "o5m3j9k1l2"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "oauth_codes",
+        sa.Column("id", sa.Integer(), autoincrement=True, nullable=False),
+        sa.Column("code", sa.String(128), nullable=False),
+        sa.Column("user_id", sa.Integer(), nullable=False),
+        sa.Column("client_id", sa.String(64), nullable=False),
+        sa.Column("redirect_uri", sa.String(512), nullable=False),
+        sa.Column("expires_at", sa.DateTime(timezone=True), nullable=False),
+        sa.Column("used_at", sa.DateTime(timezone=True), nullable=True),
+        sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.PrimaryKeyConstraint("id"),
+        sa.ForeignKeyConstraint(["user_id"], ["users.id"], ondelete="CASCADE"),
+    )
+    op.create_index("ix_oauth_code_code", "oauth_codes", ["code"], unique=True)
+    op.create_index("ix_oauth_code_user", "oauth_codes", ["user_id"])
+
+
+def downgrade() -> None:
+    op.drop_index("ix_oauth_code_user", table_name="oauth_codes")
+    op.drop_index("ix_oauth_code_code", table_name="oauth_codes")
+    op.drop_table("oauth_codes")
diff --git a/browser/templates/_types/auth/_nav.html b/browser/templates/_types/auth/_nav.html
index 9d8042a..93499a8 100644
--- a/browser/templates/_types/auth/_nav.html
+++ b/browser/templates/_types/auth/_nav.html
@@ -1,5 +1,5 @@
 {% import 'macros/links.html' as links %}
-{% call links.link(federation_url('/auth/newsletters/'), hx_select_search, select_colours, True, aclass=styles.nav_button) %}
+{% call links.link(account_url('/newsletters/'), hx_select_search, select_colours, True, aclass=styles.nav_button) %}
   newsletters
 {% endcall %}
 {% for link in account_nav_links %}
diff --git a/browser/templates/_types/auth/_newsletter_toggle.html b/browser/templates/_types/auth/_newsletter_toggle.html
index af3a4e1..8bb3f69 100644
--- a/browser/templates/_types/auth/_newsletter_toggle.html
+++ b/browser/templates/_types/auth/_newsletter_toggle.html
@@ -1,6 +1,6 @@
 <div id="nl-{{ un.newsletter_id }}" class="flex items-center">
   <button
-    hx-post="{{ federation_url('/auth/newsletter/' ~ un.newsletter_id ~ '/toggle/') }}"
+    hx-post="{{ account_url('/newsletter/' ~ un.newsletter_id ~ '/toggle/') }}"
     hx-headers='{"X-CSRFToken": "{{ csrf_token() }}"}'
     hx-target="#nl-{{ un.newsletter_id }}"
     hx-swap="outerHTML"
diff --git a/browser/templates/_types/auth/_newsletters_panel.html b/browser/templates/_types/auth/_newsletters_panel.html
index 36bc476..0f3fdbb 100644
--- a/browser/templates/_types/auth/_newsletters_panel.html
+++ b/browser/templates/_types/auth/_newsletters_panel.html
@@ -22,7 +22,7 @@
                 {# No subscription row yet — show an off toggle that will create one #}
                 <div id="nl-{{ item.newsletter.id }}" class="flex items-center">
                   <button
-                    hx-post="{{ federation_url('/auth/newsletter/' ~ item.newsletter.id ~ '/toggle/') }}"
+                    hx-post="{{ account_url('/newsletter/' ~ item.newsletter.id ~ '/toggle/') }}"
                     hx-headers='{"X-CSRFToken": "{{ csrf_token() }}"}'
                     hx-target="#nl-{{ item.newsletter.id }}"
                     hx-swap="outerHTML"
diff --git a/browser/templates/_types/auth/header/_header.html b/browser/templates/_types/auth/header/_header.html
index 5f3627e..c59a712 100644
--- a/browser/templates/_types/auth/header/_header.html
+++ b/browser/templates/_types/auth/header/_header.html
@@ -1,7 +1,7 @@
 {% import 'macros/links.html' as links %}
 {% macro header_row(oob=False) %}
   {% call links.menu_row(id='auth-row', oob=oob) %}
-    {% call links.link(federation_url('/auth/account/'), hx_select_search  ) %}
+    {% call links.link(account_url('/'), hx_select_search  ) %}
       <i class="fa-solid fa-user"></i>
       <div>account</div>
     {% endcall %}
diff --git a/browser/templates/_types/root/_full_user.html b/browser/templates/_types/root/_full_user.html
index eac72e4..b5f46cc 100644
--- a/browser/templates/_types/root/_full_user.html
+++ b/browser/templates/_types/root/_full_user.html
@@ -1,5 +1,5 @@
  
-{% set href=federation_url('/auth/account/') %}
+{% set href=account_url('/') %}
 <a
     href="{{ href }}"
     class="justify-center cursor-pointer flex flex-row items-center p-3 gap-2 rounded bg-stone-200 text-black {{select_colours}}"
diff --git a/browser/templates/_types/root/mobile/_full_user.html b/browser/templates/_types/root/mobile/_full_user.html
index 192bd12..1282e31 100644
--- a/browser/templates/_types/root/mobile/_full_user.html
+++ b/browser/templates/_types/root/mobile/_full_user.html
@@ -1,5 +1,5 @@
  
-{% set href=federation_url('/auth/account/') %}
+{% set href=account_url('/') %}
 <a
     href="{{ href }}"
     data-close-details
diff --git a/infrastructure/factory.py b/infrastructure/factory.py
index 477bc23..7394dc9 100644
--- a/infrastructure/factory.py
+++ b/infrastructure/factory.py
@@ -11,7 +11,7 @@ from shared.config import init_config, config, pretty
 from shared.models import KV  # ensure shared models imported
 # Register all app model classes with SQLAlchemy so cross-domain
 # relationship() string references resolve correctly.
-for _mod in ("blog.models", "market.models", "cart.models", "events.models", "federation.models"):
+for _mod in ("blog.models", "market.models", "cart.models", "events.models", "federation.models", "account.models"):
     try:
         __import__(_mod)
     except ImportError:
@@ -80,11 +80,10 @@ def create_base_app(
 
     app.secret_key = os.getenv("SECRET_KEY", "dev-secret-key-change-me-777")
 
-    # Session cookie shared across subdomains
-    cookie_domain = os.getenv("SESSION_COOKIE_DOMAIN")  # e.g. ".rose-ash.com"
-    if cookie_domain:
-        app.config["SESSION_COOKIE_DOMAIN"] = cookie_domain
-    app.config["SESSION_COOKIE_NAME"] = "blog_session"
+    # Per-app first-party session cookie (no shared domain — avoids Safari ITP)
+    app.config["SESSION_COOKIE_NAME"] = f"{name}_session"
+    app.config["SESSION_COOKIE_SAMESITE"] = "Lax"
+    app.config["SESSION_COOKIE_SECURE"] = True
 
     # Ghost / Redis config
     app.config["GHOST_API_URL"] = os.getenv("GHOST_API_URL")
@@ -102,6 +101,11 @@ def create_base_app(
     setup_jinja(app)
     errors(app)
 
+    # Auto-register OAuth client blueprint for non-federation apps
+    if name != "federation":
+        from shared.infrastructure.oauth import create_oauth_blueprint
+        app.register_blueprint(create_oauth_blueprint(name))
+
     # --- before-request hooks ---
     @app.before_request
     async def _route_log():
diff --git a/infrastructure/jinja_setup.py b/infrastructure/jinja_setup.py
index 8b64190..3902394 100644
--- a/infrastructure/jinja_setup.py
+++ b/infrastructure/jinja_setup.py
@@ -13,7 +13,7 @@ from shared.browser.app.csrf import generate_csrf_token
 from shared.browser.app.authz import has_access
 from shared.browser.app.filters import register as register_filters
 
-from .urls import blog_url, market_url, cart_url, events_url, federation_url, login_url, page_cart_url, market_product_url
+from .urls import blog_url, market_url, cart_url, events_url, federation_url, account_url, login_url, page_cart_url, market_product_url
 
 
 def setup_jinja(app: Quart) -> None:
@@ -98,6 +98,7 @@ def setup_jinja(app: Quart) -> None:
     app.jinja_env.globals["cart_url"] = cart_url
     app.jinja_env.globals["events_url"] = events_url
     app.jinja_env.globals["federation_url"] = federation_url
+    app.jinja_env.globals["account_url"] = account_url
     app.jinja_env.globals["login_url"] = login_url
     app.jinja_env.globals["page_cart_url"] = page_cart_url
     app.jinja_env.globals["market_product_url"] = market_product_url
diff --git a/infrastructure/oauth.py b/infrastructure/oauth.py
new file mode 100644
index 0000000..59eee38
--- /dev/null
+++ b/infrastructure/oauth.py
@@ -0,0 +1,130 @@
+"""OAuth2 client blueprint for non-federation apps.
+
+Each client app gets /auth/login, /auth/callback, /auth/logout.
+Federation is the OAuth authorization server.
+"""
+from __future__ import annotations
+
+import secrets
+from datetime import datetime, timezone
+
+from quart import (
+    Blueprint,
+    redirect,
+    request,
+    session as qsession,
+    g,
+    current_app,
+)
+from sqlalchemy import select
+
+from shared.db.session import get_session
+from shared.models import User
+from shared.models.oauth_code import OAuthCode
+from shared.infrastructure.urls import federation_url, app_url
+from shared.infrastructure.cart_identity import current_cart_identity
+from shared.events import emit_activity
+
+SESSION_USER_KEY = "uid"
+
+
+def create_oauth_blueprint(app_name: str) -> Blueprint:
+    """Return an OAuth client blueprint for *app_name*."""
+    bp = Blueprint("oauth_auth", __name__, url_prefix="/auth")
+
+    @bp.get("/login")
+    @bp.get("/login/")
+    async def login():
+        next_url = request.args.get("next", "/")
+        state = secrets.token_urlsafe(32)
+        qsession["oauth_state"] = state
+        qsession["oauth_next"] = next_url
+
+        redirect_uri = app_url(app_name, "/auth/callback")
+        authorize_url = federation_url(
+            f"/oauth/authorize?client_id={app_name}"
+            f"&redirect_uri={redirect_uri}"
+            f"&state={state}"
+        )
+        return redirect(authorize_url)
+
+    @bp.get("/callback")
+    @bp.get("/callback/")
+    async def callback():
+        code = request.args.get("code")
+        state = request.args.get("state")
+        expected_state = qsession.pop("oauth_state", None)
+        next_url = qsession.pop("oauth_next", "/")
+
+        if not code or not state or state != expected_state:
+            current_app.logger.warning("OAuth callback: bad state or missing code")
+            return redirect("/")
+
+        expected_redirect = app_url(app_name, "/auth/callback")
+        now = datetime.now(timezone.utc)
+
+        async with get_session() as s:
+            async with s.begin():
+                result = await s.execute(
+                    select(OAuthCode)
+                    .where(OAuthCode.code == code)
+                    .with_for_update()
+                )
+                oauth_code = result.scalar_one_or_none()
+
+                if not oauth_code:
+                    current_app.logger.warning("OAuth callback: code not found")
+                    return redirect("/")
+
+                if oauth_code.used_at is not None:
+                    current_app.logger.warning("OAuth callback: code already used")
+                    return redirect("/")
+
+                if oauth_code.expires_at < now:
+                    current_app.logger.warning("OAuth callback: code expired")
+                    return redirect("/")
+
+                if oauth_code.client_id != app_name:
+                    current_app.logger.warning("OAuth callback: client_id mismatch")
+                    return redirect("/")
+
+                if oauth_code.redirect_uri != expected_redirect:
+                    current_app.logger.warning("OAuth callback: redirect_uri mismatch")
+                    return redirect("/")
+
+                oauth_code.used_at = now
+                user_id = oauth_code.user_id
+
+        # Set local session
+        qsession[SESSION_USER_KEY] = user_id
+
+        # Emit login activity for cart adoption
+        ident = current_cart_identity()
+        anon_session_id = ident.get("session_id")
+        if anon_session_id:
+            try:
+                async with get_session() as s:
+                    async with s.begin():
+                        await emit_activity(
+                            s,
+                            activity_type="rose:Login",
+                            actor_uri="internal:system",
+                            object_type="Person",
+                            object_data={
+                                "user_id": user_id,
+                                "session_id": anon_session_id,
+                            },
+                        )
+            except Exception:
+                current_app.logger.exception("OAuth: failed to emit login activity")
+
+        return redirect(next_url, 303)
+
+    @bp.post("/logout")
+    @bp.post("/logout/")
+    async def logout():
+        qsession.pop(SESSION_USER_KEY, None)
+        qsession.pop("cart_sid", None)
+        return redirect("/")
+
+    return bp
diff --git a/infrastructure/urls.py b/infrastructure/urls.py
index c945397..ae67351 100644
--- a/infrastructure/urls.py
+++ b/infrastructure/urls.py
@@ -41,6 +41,10 @@ def federation_url(path: str = "/") -> str:
     return app_url("federation", path)
 
 
+def account_url(path: str = "/") -> str:
+    return app_url("account", path)
+
+
 def page_cart_url(page_slug: str, path: str = "/") -> str:
     if not path.startswith("/"):
         path = "/" + path
@@ -66,17 +70,24 @@ def market_product_url(product_slug: str, suffix: str = "", market_place=None) -
 
 
 def login_url(next_url: str = "") -> str:
-    # Auth lives in federation. Set AUTH_APP to override.
-    from quart import session as qsession
-    auth_app = os.getenv("AUTH_APP", "federation")
-    base = app_url(auth_app, "/auth/login/")
-    params: list[str] = []
+    from quart import current_app
+
+    # Federation handles login directly (magic link flow)
+    if current_app.name == "federation":
+        base = "/auth/login/"
+        params: list[str] = []
+        if next_url:
+            params.append(f"next={quote(next_url, safe='')}")
+        from quart import session as qsession
+        cart_sid = qsession.get("cart_sid")
+        if cart_sid:
+            params.append(f"cart_sid={quote(cart_sid, safe='')}")
+        if params:
+            return f"{base}?{'&'.join(params)}"
+        return base
+
+    # Client apps: local /auth/login triggers OAuth redirect to federation
+    base = "/auth/login/"
     if next_url:
-        params.append(f"next={quote(next_url, safe='')}")
-    # Pass anonymous cart session so the auth app can adopt it on login
-    cart_sid = qsession.get("cart_sid")
-    if cart_sid:
-        params.append(f"cart_sid={quote(cart_sid, safe='')}")
-    if params:
-        return f"{base}?{'&'.join(params)}"
+        return f"{base}?next={quote(next_url, safe='')}"
     return base
diff --git a/models/__init__.py b/models/__init__.py
index 7a4823c..d76422b 100644
--- a/models/__init__.py
+++ b/models/__init__.py
@@ -1,6 +1,7 @@
 from .user import User
 from .kv import KV
 from .magic_link import MagicLink
+from .oauth_code import OAuthCode
 from .menu_item import MenuItem
 
 from .ghost_membership_entities import (
diff --git a/models/oauth_code.py b/models/oauth_code.py
new file mode 100644
index 0000000..9aac2bf
--- /dev/null
+++ b/models/oauth_code.py
@@ -0,0 +1,25 @@
+from __future__ import annotations
+from datetime import datetime
+from sqlalchemy import String, Integer, DateTime, ForeignKey, func, Index
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+from shared.db.base import Base
+
+
+class OAuthCode(Base):
+    __tablename__ = "oauth_codes"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    code: Mapped[str] = mapped_column(String(128), unique=True, index=True, nullable=False)
+    user_id: Mapped[int] = mapped_column(ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True)
+    client_id: Mapped[str] = mapped_column(String(64), nullable=False)
+    redirect_uri: Mapped[str] = mapped_column(String(512), nullable=False)
+    expires_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)
+    used_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, server_default=func.now())
+
+    user = relationship("User", backref="oauth_codes")
+
+    __table_args__ = (
+        Index("ix_oauth_code_code", "code", unique=True),
+        Index("ix_oauth_code_user", "user_id"),
+    )
diff --git a/services/widget_registry.py b/services/widget_registry.py
index 0cab373..f43d8e5 100644
--- a/services/widget_registry.py
+++ b/services/widget_registry.py
@@ -48,8 +48,8 @@ class _WidgetRegistry:
         slug = w.slug
 
         def _href(s=slug):
-            from shared.infrastructure.urls import federation_url
-            return federation_url(f"/auth/{s}/")
+            from shared.infrastructure.urls import account_url
+            return account_url(f"/{s}/")
 
         self._account_nav.append(AccountNavLink(
             label=w.label,