diff --git a/api/project.py b/api/project.py
index 0853e1c..d1d9e60 100644
--- a/api/project.py
+++ b/api/project.py
@@ -3,6 +3,8 @@ from .connection import g_conn_dict as conn
 
 # no undo/redo
 
+_project_open_count: dict[str, int] = {}
+
 def have_project(name: str) -> bool:
     with pg.connect(conninfo="dbname=postgres host=127.0.0.1", autocommit=True) as conn:
         with conn.cursor() as cur:
@@ -23,11 +25,19 @@ def delete_project(name: str) -> None:
             cur.execute(f"drop database {name}")
 
 def open_project(name: str) -> None:
-    conn[name] = pg.connect(conninfo=f"dbname={name} host=127.0.0.1", autocommit=True)
+    if name not in _project_open_count:
+        conn[name] = pg.connect(conninfo=f"dbname={name} host=127.0.0.1", autocommit=True)
+        _project_open_count[name] = 0
+
+    _project_open_count[name] += 1
 
 def is_project_open(name: str) -> bool:
     return name in conn
 
 def close_project(name: str) -> None:
-    conn[name].close()
-    del conn[name]
+    if name in _project_open_count:
+        _project_open_count[name] -= 1
+        if _project_open_count[name] == 0:
+            conn[name].close()
+            del conn[name]
+            del _project_open_count[name]