diff --git a/backend/app/models.py b/backend/app/models.py
index dbdbf09..c33af44 100644
--- a/backend/app/models.py
+++ b/backend/app/models.py
@@ -4,14 +4,18 @@ import uuid
 from datetime import datetime
 from .database import Base
 
-# Compatibility layer for SQLite
+# Compatibility layer for SQLite and PostgreSQL without pgvector
 try:
     from sqlalchemy.dialects.postgresql import UUID, ARRAY
-    from pgvector.sqlalchemy import Vector
-    # Check if we are using SQLite
     import os
     if "sqlite" in os.getenv("DATABASE_URL", ""):
         raise ImportError("Using SQLite")
+    # Try to import pgvector, if fails use JSON
+    try:
+        from pgvector.sqlalchemy import Vector
+    except ImportError:
+        # No pgvector, use JSON instead
+        Vector = JSON
 except ImportError:
     from sqlalchemy.types import TypeDecorator, CHAR
     import json
@@ -38,7 +42,6 @@ except ImportError:
             if value is None: return None
             return json.loads(value)
 
-    # Use JSON for ARRAY in SQLite
     ARRAY = JSON
 
 class ContextNode(Base):