diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..e6b69f7
--- /dev/null
+++ b/.envrc
@@ -0,0 +1,3 @@
+if has nix; then
+  use flake .
+fi
diff --git a/.gitignore b/.gitignore
index d787b70..ca1ab72 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 /target
 /result
+.direnv/*
diff --git a/flake.nix b/flake.nix
index 998d52b..f024f27 100644
--- a/flake.nix
+++ b/flake.nix
@@ -161,7 +161,9 @@
           # MY_CUSTOM_DEVELOPMENT_VAR = "something else";
 
           # Extra inputs can be added here; cargo and rustc are provided by default.
-          packages = [
+          packages = with pkgs; [
+            rustup
+            toolchain
             # pkgs.ripgrep
           ];
         };
diff --git a/src/main.rs b/src/main.rs
index 168661b..408e780 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,4 +1,7 @@
-/// GPLv3  2024 KLM banana bread©
+#![feature(test)]
+
+extern crate test;
+
 use chrono::prelude::*;
 use std::{env, io};
 use utils::print_time_delta;
@@ -73,6 +76,7 @@ mod utils {
     #[cfg(test)]
     mod tests {
         use super::*;
+        use test::{black_box, Bencher};
 
         const DATE: &str = "1998-01-20T16:00:00+01:00";
 
@@ -157,6 +161,15 @@ mod utils {
             );
         }
 
+        #[bench]
+        fn bench_parse_timestamp_hms(b: &mut Bencher) {
+            b.iter(|| {
+                for i in 1..1000 {
+                    black_box(parse_timestamp(&get_ctx(), &"23:59:59".to_string()));
+                }
+            })
+        }
+
         #[test]
         #[should_panic(expected = "Couldn't parse timestamp.")]
         fn parse_timestamp_hms_highh() {