diff --git a/sachy-config/src/lib.rs b/sachy-config/src/lib.rs
--- a/sachy-config/src/lib.rs
+++ b/sachy-config/src/lib.rs
@@ -89,6 +89,8 @@
                 "i64" => validate_kind_to_string::<i64>(name, kind, value)?,
                 "u128" => validate_kind_to_string::<u128>(name, kind, value)?,
                 "i128" => validate_kind_to_string::<i128>(name, kind, value)?,
+                "usize" => validate_kind_to_string::<usize>(name, kind, value)?,
+                "isize" => validate_kind_to_string::<isize>(name, kind, value)?,
                 "f32" => validate_kind_to_string::<f32>(name, kind, value)?,
                 "f64" => validate_kind_to_string::<f64>(name, kind, value)?,
                 "&str" => bail!("{} is a {}, use [statics] for these", name, kind),