diff --git a/backend/constants.py b/backend/constants.py
index e1086c9..bfddb72 100644
--- a/backend/constants.py
+++ b/backend/constants.py
@@ -1,9 +1,11 @@
 import os
 
-
 DATABASE_URL = "sqlite:///./data/database.db"
 JWT_ALGORITHM = "HS256"
-ACCESS_TOKEN_EXPIRE_HOURS = 24
+# Token inactivity expiration - token expires if not used for this duration
+TOKEN_INACTIVITY_EXPIRE_HOURS = 30 * 24  # 30 days of inactivity
+# Maximum token lifetime (safety net) - tokens expire after this regardless of usage
+MAX_TOKEN_LIFETIME_HOURS = 365 * 24  # 1 year maximum
 OWNER_USERNAME = "denis0001-dev"
 JWT_SECRET_KEY = os.getenv("JWT_SECRET")
 
diff --git a/backend/dependencies.py b/backend/dependencies.py
index c19adee..6ebb55b 100644
--- a/backend/dependencies.py
+++ b/backend/dependencies.py
@@ -1,4 +1,4 @@
-from datetime import datetime
+from datetime import datetime, timedelta
 from fastapi import Depends, HTTPException, Request, status
 from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer
 from sqlalchemy.orm import Session
@@ -66,7 +66,20 @@ def get_current_user(
             headers={"WWW-Authenticate": "Bearer"},
         )
 
-    # Touch last_seen on valid session
+    # Check if session has been inactive for too long (sliding expiration)
+    from constants import TOKEN_INACTIVITY_EXPIRE_HOURS
+    inactivity_threshold = datetime.now() - timedelta(hours=TOKEN_INACTIVITY_EXPIRE_HOURS)
+    if device_session.last_seen < inactivity_threshold:
+        # Session expired due to inactivity - revoke it
+        device_session.revoked = True
+        db.commit()
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Session expired due to inactivity",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+
+    # Touch last_seen on valid session (sliding expiration - extends token life)
     device_session.last_seen = datetime.now()
     db.commit()
 
diff --git a/backend/utils.py b/backend/utils.py
index 660b475..ac2cd5a 100644
--- a/backend/utils.py
+++ b/backend/utils.py
@@ -4,16 +4,17 @@ import jwt
 from typing import Optional, Any
 import bcrypt
 
-from constants import ACCESS_TOKEN_EXPIRE_HOURS, JWT_SECRET_KEY, JWT_ALGORITHM
+from constants import MAX_TOKEN_LIFETIME_HOURS, JWT_SECRET_KEY, JWT_ALGORITHM
 
 # JWT Helper Functions
 def create_token(user_id: int, username: str, session_id: str) -> str:
-    expire = datetime.now() + timedelta(hours=ACCESS_TOKEN_EXPIRE_HOURS)
+    # Set a long expiration as safety net (actual expiration based on inactivity)
+    expire = datetime.now() + timedelta(hours=MAX_TOKEN_LIFETIME_HOURS)
     payload = {
         "user_id": user_id,
         "username": username,
         "session_id": session_id,
-        "exp": expire
+        "exp": int(expire.timestamp())  # JWT exp must be Unix timestamp (int)
     }
     return jwt.encode(payload, JWT_SECRET_KEY, algorithm=JWT_ALGORITHM)