diff --git a/.gitignore b/.gitignore
index d97f62e..67e0e9c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@
 .DS_Store
 .idea
 .direnv/
+/result
diff --git a/flake.lock b/flake.lock
index a62c24a..8d2d0df 100644
--- a/flake.lock
+++ b/flake.lock
@@ -1,12 +1,32 @@
 {
   "nodes": {
+    "naersk": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1721727458,
+        "narHash": "sha256-r/xppY958gmZ4oTfLiHN0ZGuQ+RSTijDblVgVLFi1mw=",
+        "owner": "nix-community",
+        "repo": "naersk",
+        "rev": "3fb418eaf352498f6b6c30592e3beb63df42ef11",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "naersk",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1703499205,
-        "narHash": "sha256-lF9rK5mSUfIZJgZxC3ge40tp1gmyyOXZ+lRY3P8bfbg=",
+        "lastModified": 1728538411,
+        "narHash": "sha256-f0SBJz1eZ2yOuKUr5CA9BHULGXVSn6miBuUWdTyhUhU=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "e1fa12d4f6c6fe19ccb59cac54b5b3f25e160870",
+        "rev": "b69de56fac8c2b6f8fd27f2eca01dcda8e0a4221",
         "type": "github"
       },
       "original": {
@@ -18,10 +38,32 @@
     },
     "root": {
       "inputs": {
+        "naersk": "naersk",
         "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay",
         "utils": "utils"
       }
     },
+    "rust-overlay": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1728700003,
+        "narHash": "sha256-Ox1pvEHxLK6lAdaKQW21Zvk65SPDag+cD8YA444R/og=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "fc1e58ebabe0cef4442eedea07556ff0c9eafcfe",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
+      }
+    },
     "systems": {
       "locked": {
         "lastModified": 1681028828,
@@ -42,11 +84,11 @@
         "systems": "systems"
       },
       "locked": {
-        "lastModified": 1701680307,
-        "narHash": "sha256-kAuep2h5ajznlPMD9rnQyffWG8EM/C73lejGofXvdM8=",
+        "lastModified": 1726560853,
+        "narHash": "sha256-X6rJYSESBVr3hBoH0WbKE5KvhPU5bloyZ2L4K60/fPQ=",
         "owner": "numtide",
         "repo": "flake-utils",
-        "rev": "4022d587cbbfd70fe950c1e2083a02621806a725",
+        "rev": "c1dfcf08411b08f6b8615f7d8971a2bfa81d5e8a",
         "type": "github"
       },
       "original": {
diff --git a/flake.nix b/flake.nix
index dccdd6c..936e777 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,41 +1,72 @@
 {
   description = "Leet your code in command-line.";
 
-  inputs.nixpkgs.url      = "github:NixOS/nixpkgs/nixpkgs-unstable";
-  inputs.utils.url        = "github:numtide/flake-utils";
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    utils.url = "github:numtide/flake-utils";
 
-  outputs = { self, nixpkgs, utils, ... }:
+    naersk = {
+      url = "github:nix-community/naersk";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    utils,
+    naersk,
+    rust-overlay,
+    ...
+    }:
     utils.lib.eachDefaultSystem (system:
       let
-        pkgs = import nixpkgs { inherit system; };
+        overlays = [ (import rust-overlay) ];
+
+        pkgs = (import nixpkgs) {
+          inherit system overlays;
+        };
+
+        toolchain = pkgs.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml;
+
+        naersk' = pkgs.callPackage naersk {
+          cargo = toolchain;
+          rustc = toolchain;
+          clippy = toolchain;
+        };
 
         nativeBuildInputs = with pkgs; [
           pkg-config
         ];
 
+        darwinBuildInputs = pkgs.lib.optionals pkgs.stdenv.isDarwin [
+          pkgs.darwin.apple_sdk.frameworks.Security
+          pkgs.darwin.apple_sdk.frameworks.SystemConfiguration
+        ];
+
         buildInputs = with pkgs; [
           openssl
           dbus
           sqlite
-        ] ++ lib.optionals stdenv.isDarwin [ darwin.apple_sdk.frameworks.Security ];
+        ] ++ darwinBuildInputs;
 
-
-        package = with pkgs; rustPlatform.buildRustPackage rec {
+        package = naersk'.buildPackage rec {
           pname = "leetcode-cli";
-          version = "0.4.3";
-          src = fetchCrate {
-            inherit pname version;
-            sha256 = "sha256-y5zh93WPWSMDXqYangqrxav+sC0b0zpFIp6ZIew6KMo=";
-          };
-          cargoSha256 = "sha256-VktDiLsU+GOsa6ba9JJZGEPTavSKp+aSZm2dfhPEqMs=";
+          version = "git";
+
+          src = ./.;
+          doCheck = true; # run `cargo test` on build
 
           inherit buildInputs nativeBuildInputs;
 
-          # a nightly compiler is required unless we use this cheat code.
-          RUSTC_BOOTSTRAP = 0;
+          buildNoDefaultFeatures = true;
 
-          # CFG_RELEASE = "${rustPlatform.rust.rustc.version}-stable";
-          CFG_RELEASE_CHANNEL = "stable";
+          buildFeatures = "git";
 
           meta = with pkgs.lib; {
             description = "Leet your code in command-line.";
@@ -44,9 +75,16 @@
             maintainers = with maintainers; [ congee ];
             mainProgram = "leetcode";
           };
+
+          # Env vars
+          # a nightly compiler is required unless we use this cheat code.
+          RUSTC_BOOTSTRAP = 0;
+
+          # CFG_RELEASE = "${rustPlatform.rust.rustc.version}-stable";
+          CFG_RELEASE_CHANNEL = "stable";
         };
       in
-      {
+        {
         defaultPackage = package;
         overlay = final: prev: { leetcode-cli = package; };
 
@@ -55,11 +93,7 @@
           inherit nativeBuildInputs;
 
           buildInputs = buildInputs ++ [
-            rustc
-            cargo
-            rustfmt
-            clippy
-            rust-analyzer
+            toolchain
             cargo-edit
             cargo-bloat
             cargo-audit
diff --git a/rust-toolchain.toml b/rust-toolchain.toml
new file mode 100644
index 0000000..2a19081
--- /dev/null
+++ b/rust-toolchain.toml
@@ -0,0 +1,10 @@
+[toolchain]
+channel = "stable"
+components = [
+  "rustc",
+  "cargo",
+  "rustfmt",
+  "clippy",
+  "rust-analyzer",
+]
+profile = "minimal"