diff --git a/.gitignore b/.gitignore
index 599be4e..7ef61a4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@
 *.ez
 /build
 erl_crash.dump
+.envrc
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..42b5046
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,48 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1783279667,
+        "narHash": "sha256-/NAkDSsve+GNM0Bt6tleJdCGfsTlK89nPjkVOzZMo0s=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "f205b5574fd0cb7da5b702a2da51507b7f4fdd1b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "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..b91698d
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,41 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    treefmt-nix = {
+      url = "github:numtide/treefmt-nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    treefmt-nix,
+    ...
+  }: let
+    lib = nixpkgs.lib;
+    supportedSystems = ["x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin"];
+    forEachSupportedSystem = f:
+      lib.genAttrs supportedSystems (system:
+        f {
+          pkgs = import nixpkgs {inherit system;};
+        });
+    treefmtEval = forEachSupportedSystem ({pkgs}: treefmt-nix.lib.evalModule pkgs ./treefmt.nix);
+  in {
+    devShells = forEachSupportedSystem ({pkgs}: {
+      default = pkgs.mkShell {
+        packages = with pkgs; [
+          gleam
+          beamMinimal29Packages.erlang
+          beamMinimal29Packages.rebar3
+        ];
+      };
+    });
+
+    formatter = forEachSupportedSystem ({pkgs}: treefmtEval.${pkgs.stdenv.hostPlatform.system}.config.build.wrapper);
+    checks = forEachSupportedSystem ({pkgs}: {
+      formatting =
+        treefmtEval.${pkgs.stdenv.hostPlatform.system}.config.build.check self;
+    });
+  };
+}
diff --git a/treefmt.nix b/treefmt.nix
new file mode 100644
index 0000000..15a8d59
--- /dev/null
+++ b/treefmt.nix
@@ -0,0 +1,5 @@
+{pkgs, ...}: {
+  projectRootFile = "flake.nix";
+  programs.gleam.enable = true;
+  programs.alejandra.enable = true;
+}