diff --git a/.ci_support/environment-old.yml b/.ci_support/environment-old.yml
index 747693da8..9c0cb8e26 100644
--- a/.ci_support/environment-old.yml
+++ b/.ci_support/environment-old.yml
@@ -11,6 +11,7 @@ dependencies:
 - pandas =2.0.0
 - pint =0.18
 - psutil =5.8.0
+- psycopg2 =2.9.3
 - pyfileindex =0.0.16
 - pyiron_snippets =0.1.3
 - executorlib =0.0.1
diff --git a/.ci_support/environment.yml b/.ci_support/environment.yml
index 82c0e3573..e94b8db14 100644
--- a/.ci_support/environment.yml
+++ b/.ci_support/environment.yml
@@ -15,6 +15,7 @@ dependencies:
 - pandas =2.2.3
 - pint =0.24.3
 - psutil =6.0.0
+- psycopg2 =2.9.9
 - pyfileindex =0.0.29
 - pyiron_snippets =0.1.4
 - executorlib =0.0.2
diff --git a/pyproject.toml b/pyproject.toml
index 5f7dec14a..73b97cb90 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -60,6 +60,9 @@ flux = [
 stats = [
     "pint==0.24.3",
 ]
+postgres = [
+    "psycopg2==2.9.9"
+]
 
 [project.scripts]
 pyiron = "pyiron_base.cli:main"