diff --git a/surfsense_backend/alembic/versions/73_add_chat_session_state_table.py b/surfsense_backend/alembic/versions/73_add_chat_session_state_table.py
new file mode 100644
index 000000000..12e99f306
--- /dev/null
+++ b/surfsense_backend/alembic/versions/73_add_chat_session_state_table.py
@@ -0,0 +1,75 @@
+"""Add chat_session_state table for live collaboration
+
+Revision ID: 73
+Revises: 72
+
+Creates chat_session_state table to track AI responding state per thread.
+Enables real-time sync via Electric SQL for shared chat collaboration.
+"""
+
+from collections.abc import Sequence
+
+from alembic import op
+
+revision: str = "73"
+down_revision: str | None = "72"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    """Create chat_session_state table with Electric SQL replication."""
+    op.execute(
+        """
+        CREATE TABLE IF NOT EXISTS chat_session_state (
+            id SERIAL PRIMARY KEY,
+            thread_id INTEGER NOT NULL REFERENCES new_chat_threads(id) ON DELETE CASCADE,
+            ai_responding_to_user_id UUID REFERENCES "user"(id) ON DELETE SET NULL,
+            updated_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+            UNIQUE (thread_id)
+        )
+        """
+    )
+
+    op.execute(
+        "CREATE INDEX IF NOT EXISTS idx_chat_session_state_thread_id ON chat_session_state(thread_id)"
+    )
+
+    op.execute("ALTER TABLE chat_session_state REPLICA IDENTITY FULL;")
+
+    op.execute(
+        """
+        DO $$
+        BEGIN
+            IF NOT EXISTS (
+                SELECT 1 FROM pg_publication_tables 
+                WHERE pubname = 'electric_publication_default' 
+                AND tablename = 'chat_session_state'
+            ) THEN
+                ALTER PUBLICATION electric_publication_default ADD TABLE chat_session_state;
+            END IF;
+        END
+        $$;
+        """
+    )
+
+
+def downgrade() -> None:
+    """Drop chat_session_state table and remove from Electric SQL replication."""
+    op.execute(
+        """
+        DO $$
+        BEGIN
+            IF EXISTS (
+                SELECT 1 FROM pg_publication_tables 
+                WHERE pubname = 'electric_publication_default' 
+                AND tablename = 'chat_session_state'
+            ) THEN
+                ALTER PUBLICATION electric_publication_default DROP TABLE chat_session_state;
+            END IF;
+        END
+        $$;
+        """
+    )
+
+    op.execute("DROP TABLE IF EXISTS chat_session_state;")