diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..3550a30
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+use flake
diff --git a/.gitignore b/.gitignore
index 460cbe1..3baef8c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+.direnv
 /findr
 /findr-prof
 *.spall
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..9ecfd2a
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,99 @@
+{
+  "nodes": {
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": "nixpkgs-lib"
+      },
+      "locked": {
+        "lastModified": 1778716662,
+        "narHash": "sha256-m1Yf0wZ8j1OHjTc2UwHwyQRSnNeSgLJOd7q5Y45hzi4=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "f7c1a2d347e4c52d5fb8d10cb4d94b5884e546fb",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1767313136,
+        "narHash": "sha256-16KkgfdYqjaeRGBaYsNrhPRRENs0qzkQVUooNHtoy2w=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "ac62194c3917d5f474c1a844b6fd6da2db95077d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-25.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-lib": {
+      "locked": {
+        "lastModified": 1777168982,
+        "narHash": "sha256-GOkGPcboWE9BmGCRMLX3worL4EMnsnG8MyKmXNeYuhQ=",
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "rev": "f5901329dade4a6ea039af1433fb087bd9c1fe14",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "type": "github"
+      }
+    },
+    "nixpkgs-unstable": {
+      "locked": {
+        "lastModified": 1781173989,
+        "narHash": "sha256-fnzKKPvS+oieI/pTzotA5tkoM47EB1NpaBcgk4R97hE=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "8c91a71d13451abc40eb9dae8910f972f979852f",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-parts": "flake-parts",
+        "nixpkgs": "nixpkgs",
+        "nixpkgs-unstable": "nixpkgs-unstable",
+        "treefmt-nix": "treefmt-nix"
+      }
+    },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1780220602,
+        "narHash": "sha256-eynAfOmbmxJnkp7YewvCEbShNnnYJ9gLLqkzsYtBPeM=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "db947814a175b7ca6ded66e21383d938df01c227",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..aa50bf0
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,127 @@
+{
+  description = "Manage your .env files.";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.05";
+    nixpkgs-unstable.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    treefmt-nix.url = "github:numtide/treefmt-nix";
+    treefmt-nix.inputs.nixpkgs.follows = "nixpkgs";
+  };
+
+  outputs =
+    inputs@{
+      flake-parts,
+      nixpkgs,
+      nixpkgs-unstable,
+      self,
+      treefmt-nix,
+    }:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      imports = [
+        inputs.treefmt-nix.flakeModule
+      ];
+      systems = [
+        "x86_64-linux"
+        "aarch64-linux"
+
+        "aarch64-darwin"
+      ];
+
+      perSystem =
+        {
+          pkgs,
+          system,
+          inputs',
+          ...
+        }:
+        let
+          mysqlite = pkgs.sqlite.overrideAttrs (old: {
+            configureFlags = (old.configureFlags or [ ]) ++ [ "--enable-deserialize" ];
+          });
+        in
+        {
+          _module.args.pkgs = import nixpkgs {
+            inherit system;
+            config.allowUnfree = true;
+
+            overlays = [
+              (_final: _prev: { unstable = inputs'.nixpkgs-unstable.legacyPackages; })
+            ];
+          };
+
+          treefmt = {
+            projectRootFile = "flake.nix";
+            settings.global.excludes = [
+              ".direnv/**"
+              ".jj/**"
+              ".env"
+              ".envrc"
+              ".env.local"
+            ];
+
+            programs.nixpkgs-fmt.enable = true;
+          };
+
+          packages.default = pkgs.stdenv.mkDerivation rec {
+            pname = "envr";
+            version = "0.3.0";
+            src = ./.;
+
+            nativeBuildInputs = [
+              pkgs.unstable.odin
+              pkgs.pkg-config
+            ];
+
+            buildInputs = [
+              pkgs.libsodium
+              mysqlite
+            ];
+
+            doCheck = true;
+            checkPhase = ''
+              runHook preCheck
+              odin test . -all-packages
+              runHook postCheck
+            '';
+
+            buildPhase = ''
+              runHook preBuild
+              echo '${version}' > version.txt
+              odin build . -o:speed -out:${pname}
+              runHook postBuild
+            '';
+
+            installPhase = ''
+              runHook preInstall
+              install -Dm755 ${pname} $out/bin/${pname}
+              runHook postInstall
+            '';
+          };
+
+          devShells.default = pkgs.mkShell {
+            buildInputs = with pkgs; [
+              nushell
+
+              libsodium
+              mysqlite
+              unstable.odin
+              unstable.ols
+
+              # Build tools
+              zip
+
+              # Helper tools
+              delta
+              hyperfine
+
+              # IDE
+              unstable.helix
+              typescript-language-server
+              vscode-langservers-extracted
+            ];
+          };
+        };
+    };
+}