diff --git a/containers/clearview/src/clearview_app/auth/models.py b/containers/clearview/src/clearview_app/auth/models.py
index 7317812..3736ca1 100644
--- a/containers/clearview/src/clearview_app/auth/models.py
+++ b/containers/clearview/src/clearview_app/auth/models.py
@@ -9,7 +9,7 @@ from __future__ import annotations
 from datetime import datetime, timezone
 from typing import Any
 
-from sqlalchemy import Boolean, DateTime, ForeignKey, Integer, JSON, String, Text
+from sqlalchemy import Boolean, DateTime, ForeignKey, Integer, JSON, String, Text, TypeDecorator
 from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column
 
 
@@ -17,6 +17,32 @@ def _utcnow() -> datetime:
     return datetime.now(timezone.utc)
 
 
+class UTCDateTime(TypeDecorator):
+    """DateTime that always returns tz-aware UTC values.
+
+    SQLite (used in tests) does not preserve tzinfo on roundtrip even with
+    ``DateTime(timezone=True)``. This decorator normalises stored and loaded
+    values to UTC-aware datetimes so app code can rely on tz arithmetic.
+    """
+
+    impl = DateTime(timezone=True)
+    cache_ok = True
+
+    def process_bind_param(self, value, dialect):
+        if value is None:
+            return None
+        if value.tzinfo is None:
+            value = value.replace(tzinfo=timezone.utc)
+        return value.astimezone(timezone.utc)
+
+    def process_result_value(self, value, dialect):
+        if value is None:
+            return None
+        if value.tzinfo is None:
+            return value.replace(tzinfo=timezone.utc)
+        return value.astimezone(timezone.utc)
+
+
 class Base(DeclarativeBase):
     pass
 
@@ -29,8 +55,8 @@ class User(Base):
     password_hash: Mapped[str] = mapped_column(Text, nullable=False)
     role: Mapped[str] = mapped_column(String(16), nullable=False)
     is_active: Mapped[bool] = mapped_column(Boolean, nullable=False, default=True)
-    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_utcnow, nullable=False)
-    updated_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_utcnow, nullable=False)
+    created_at: Mapped[datetime] = mapped_column(UTCDateTime(), default=_utcnow, nullable=False)
+    updated_at: Mapped[datetime] = mapped_column(UTCDateTime(), default=_utcnow, nullable=False)
 
 
 class UserSession(Base):
@@ -40,9 +66,9 @@ class UserSession(Base):
     user_id: Mapped[int] = mapped_column(
         Integer, ForeignKey("users.id", ondelete="CASCADE"), nullable=False, index=True
     )
-    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_utcnow, nullable=False)
-    expires_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False, index=True)
-    last_seen_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_utcnow, nullable=False)
+    created_at: Mapped[datetime] = mapped_column(UTCDateTime(), default=_utcnow, nullable=False)
+    expires_at: Mapped[datetime] = mapped_column(UTCDateTime(), nullable=False, index=True)
+    last_seen_at: Mapped[datetime] = mapped_column(UTCDateTime(), default=_utcnow, nullable=False)
     ip: Mapped[str | None] = mapped_column(String(64), nullable=True)
     user_agent: Mapped[str | None] = mapped_column(Text, nullable=True)
     remember: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False)
@@ -52,7 +78,7 @@ class AuthAudit(Base):
     __tablename__ = "auth_audit"
 
     id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
-    ts: Mapped[datetime] = mapped_column(DateTime(timezone=True), default=_utcnow, nullable=False, index=True)
+    ts: Mapped[datetime] = mapped_column(UTCDateTime(), default=_utcnow, nullable=False, index=True)
     user_id: Mapped[int | None] = mapped_column(
         Integer, ForeignKey("users.id", ondelete="SET NULL"), nullable=True
     )
diff --git a/containers/clearview/src/clearview_app/auth/sessions.py b/containers/clearview/src/clearview_app/auth/sessions.py
new file mode 100644
index 0000000..2263f1f
--- /dev/null
+++ b/containers/clearview/src/clearview_app/auth/sessions.py
@@ -0,0 +1,72 @@
+"""Session lifecycle: create, look up + refresh, revoke, purge expired."""
+from __future__ import annotations
+
+from datetime import datetime, timedelta, timezone
+
+from sqlalchemy import delete
+from sqlalchemy.orm import Session
+
+from .models import UserSession
+from .security import new_session_id
+
+SLIDING_TTL = timedelta(hours=8)
+REMEMBER_TTL = timedelta(days=30)
+
+
+def _utcnow() -> datetime:
+    return datetime.now(timezone.utc)
+
+
+def create_session(
+    db: Session,
+    *,
+    user_id: int,
+    remember: bool,
+    ip: str | None,
+    user_agent: str | None,
+) -> tuple[str, datetime]:
+    ttl = REMEMBER_TTL if remember else SLIDING_TTL
+    expires = _utcnow() + ttl
+    sid = new_session_id()
+    db.add(
+        UserSession(
+            id=sid,
+            user_id=user_id,
+            expires_at=expires,
+            ip=ip,
+            user_agent=user_agent,
+            remember=remember,
+        )
+    )
+    db.flush()
+    return sid, expires
+
+
+def lookup_and_refresh(db: Session, sid: str | None) -> UserSession | None:
+    if not sid:
+        return None
+    row = db.get(UserSession, sid)
+    if row is None:
+        return None
+    now = _utcnow()
+    expires = row.expires_at if row.expires_at.tzinfo else row.expires_at.replace(tzinfo=timezone.utc)
+    if expires <= now:
+        return None
+    row.last_seen_at = now
+    if not row.remember:
+        row.expires_at = now + SLIDING_TTL
+    return row
+
+
+def revoke(db: Session, sid: str) -> None:
+    db.execute(delete(UserSession).where(UserSession.id == sid))
+
+
+def revoke_all_for_user(db: Session, user_id: int) -> int:
+    res = db.execute(delete(UserSession).where(UserSession.user_id == user_id))
+    return res.rowcount or 0
+
+
+def purge_expired(db: Session) -> int:
+    res = db.execute(delete(UserSession).where(UserSession.expires_at <= _utcnow()))
+    return res.rowcount or 0
diff --git a/containers/clearview/tests/test_sessions.py b/containers/clearview/tests/test_sessions.py
new file mode 100644
index 0000000..3093ace
--- /dev/null
+++ b/containers/clearview/tests/test_sessions.py
@@ -0,0 +1,79 @@
+from datetime import datetime, timedelta, timezone
+
+import pytest
+
+from clearview_app.auth import sessions as S
+from clearview_app.auth.models import User, UserSession
+
+
+@pytest.fixture()
+def user(db_session):
+    u = User(username="alice", password_hash="x", role="admin")
+    db_session.add(u); db_session.commit(); db_session.refresh(u)
+    return u
+
+
+def test_create_session_sliding(db_session, user):
+    sid, expires = S.create_session(db_session, user_id=user.id, remember=False, ip=None, user_agent=None)
+    db_session.commit()
+    assert len(sid) == 32
+    row = db_session.get(UserSession, sid)
+    assert row.remember is False
+    delta = row.expires_at - datetime.now(timezone.utc)
+    assert timedelta(hours=7, minutes=55) < delta < timedelta(hours=8, minutes=5)
+
+
+def test_create_session_remember(db_session, user):
+    sid, _ = S.create_session(db_session, user_id=user.id, remember=True, ip=None, user_agent=None)
+    db_session.commit()
+    row = db_session.get(UserSession, sid)
+    delta = row.expires_at - datetime.now(timezone.utc)
+    assert delta > timedelta(days=29)
+
+
+def test_lookup_refresh_sliding_extends(db_session, user):
+    sid, _ = S.create_session(db_session, user_id=user.id, remember=False, ip=None, user_agent=None)
+    db_session.commit()
+    row = db_session.get(UserSession, sid)
+    row.expires_at = datetime.now(timezone.utc) + timedelta(minutes=5)
+    db_session.commit()
+    looked = S.lookup_and_refresh(db_session, sid)
+    db_session.commit()
+    assert looked is not None
+    assert looked.expires_at - datetime.now(timezone.utc) > timedelta(hours=7)
+
+
+def test_lookup_refresh_remember_does_not_slide(db_session, user):
+    sid, _ = S.create_session(db_session, user_id=user.id, remember=True, ip=None, user_agent=None)
+    db_session.commit()
+    before = db_session.get(UserSession, sid).expires_at
+    S.lookup_and_refresh(db_session, sid)
+    db_session.commit()
+    after = db_session.get(UserSession, sid).expires_at
+    assert before == after
+
+
+def test_expired_session_returns_none(db_session, user):
+    sid, _ = S.create_session(db_session, user_id=user.id, remember=False, ip=None, user_agent=None)
+    row = db_session.get(UserSession, sid)
+    row.expires_at = datetime.now(timezone.utc) - timedelta(minutes=1)
+    db_session.commit()
+    assert S.lookup_and_refresh(db_session, sid) is None
+
+
+def test_revoke(db_session, user):
+    sid, _ = S.create_session(db_session, user_id=user.id, remember=False, ip=None, user_agent=None)
+    db_session.commit()
+    S.revoke(db_session, sid); db_session.commit()
+    assert db_session.get(UserSession, sid) is None
+
+
+def test_purge_expired(db_session, user):
+    fresh, _ = S.create_session(db_session, user_id=user.id, remember=False, ip=None, user_agent=None)
+    stale, _ = S.create_session(db_session, user_id=user.id, remember=False, ip=None, user_agent=None)
+    db_session.get(UserSession, stale).expires_at = datetime.now(timezone.utc) - timedelta(hours=1)
+    db_session.commit()
+    removed = S.purge_expired(db_session); db_session.commit()
+    assert removed == 1
+    assert db_session.get(UserSession, fresh) is not None
+    assert db_session.get(UserSession, stale) is None