diff --git a/pyproject.toml b/pyproject.toml
index 1291f22..74a239c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -18,7 +18,12 @@ sqlmodel = "^0.0.8"
 confz = "^2.0.0"
 psycopg2-binary = "^2.9.6"
 pydase = "*"
-tiqi-rpc = { git = "ssh://git@gitlab.phys.ethz.ch/tiqi-projects/tiqi-rpc-python.git" }
+
+# optional dependencies
+tiqi-rpc = { git = "ssh://git@gitlab.phys.ethz.ch/tiqi-projects/tiqi-rpc-python.git", optional=true }
+
+[tool.poetry.extras]
+ionizer = ["tiqi-rpc"]
 
 [tool.poetry.group.dev]
 optional = true