diff --git a/src/genesis/server/app.py b/src/genesis/server/app.py
index c9d7c5f..bb53563 100644
--- a/src/genesis/server/app.py
+++ b/src/genesis/server/app.py
@@ -154,11 +154,11 @@ def create_app(
         return {"session_id": rec.session_id, "status": rec.status, "name": rec.name}
 
     @app.get("/api/sessions")
-    def list_sessions(user_id: str = "default"):
+    def list_sessions(user_id: str = "default", project: str | None = None):
         return [
             {"session_id": r.session_id, "name": r.name, "project": r.project,
              "status": r.status, "updated_at": r.updated_at}
-            for r in service.store.list_sessions(user_id)
+            for r in service.store.list_sessions(user_id, project=project)
         ]
 
     @app.get("/api/sessions/{sid}")
diff --git a/tests/test_server_api.py b/tests/test_server_api.py
index 32177db..b7883e2 100644
--- a/tests/test_server_api.py
+++ b/tests/test_server_api.py
@@ -347,3 +347,12 @@ def test_generate_with_project_config_no_template_upload(client):
     gen = client.post(f"/api/sessions/{sid}/generate", json={})
     assert gen.status_code == 200, gen.text
     assert client.get(f"/api/sessions/{sid}/result/download").status_code == 200
+
+def test_api_list_sessions_filter_by_project(client):
+    r0 = client.post("/api/sessions", json={"user_id": "u1", "project": "stock"})
+    r1 = client.post("/api/sessions", json={"user_id": "u1", "project": "other"})
+    res = client.get("/api/sessions", params={"user_id": "u1", "project": "stock"})
+    assert res.status_code == 200
+    ids = {x["session_id"] for x in res.json()}
+    assert r0.json()["session_id"] in ids
+    assert r1.json()["session_id"] not in ids