diff --git a/default.nix b/default.nix
deleted file mode 100644
index e40c708..0000000
--- a/default.nix
+++ /dev/null
@@ -1,27 +0,0 @@
-{ ... }:
-let
-  sources = import nix/sources.nix;
-  pkgs = import sources.nixpkgs { };
-  gitignore = import sources.gitignore { };
-in pkgs.stdenv.mkDerivation {
-  name = "elo-anything";
-  src = gitignore.gitignoreSource ./.;
-
-  buildInputs = [ pkgs.elmPackages.elm pkgs.elmPackages.elm-test ];
-  buildPhase = pkgs.elmPackages.fetchElmDeps {
-    elmPackages = import ./nix/elm-srcs.nix;
-    elmVersion = "0.19.1";
-    registryDat = ./nix/registry.dat;
-  };
-
-  doCheck = true;
-  checkPhase = ''
-    env ELM_HOME=.elm elm-test
-  '';
-
-  installPhase = ''
-    make dist
-    mkdir -p $out/share/
-    mv dist $out/share/elo-anything
-  '';
-}
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..f2ceea5
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,43 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1631561581,
+        "narHash": "sha256-3VQMV5zvxaVLvqqUrNz3iJelLw30mIVSfZmAaauM3dA=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "7e5bf3925f6fbdfaf50a2a7ca0be2879c4261d19",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1631562492,
+        "narHash": "sha256-RMXh3Ol04TOdes/gl8GI0Q+8PH7kEeXbHzL0e957/Vc=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "f789739acc4baf042c85f2f7382f4b0af5c5e049",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "release-21.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..adb8fff
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,56 @@
+{
+  inputs = {
+    flake-utils.url = "github:numtide/flake-utils";
+    nixpkgs.url = "github:NixOS/nixpkgs/release-21.05";
+  };
+
+  outputs = { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let pkgs = nixpkgs.legacyPackages.${system};
+      in rec {
+        # `nix build`
+        packages.elo-anything = pkgs.stdenv.mkDerivation {
+          name = "elo-anything";
+          src = ./.;
+
+          buildInputs = [ pkgs.elmPackages.elm pkgs.elmPackages.elm-test ];
+          buildPhase = pkgs.elmPackages.fetchElmDeps {
+            elmPackages = import ./nix/elm-srcs.nix;
+            elmVersion = "0.19.1";
+            registryDat = ./nix/registry.dat;
+          };
+
+          doCheck = true;
+          checkPhase = ''
+            env ELM_HOME=.elm elm-test
+          '';
+
+          installPhase = ''
+            make dist
+            mkdir -p $out/share/
+            mv dist $out/share/elo-anything
+          '';
+        };
+        defaultPackage = packages.elo-anything;
+        overlay = final: prev: { elo-anything = packages.elo-anything; };
+
+        # `nix shell`
+        devShell = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            git
+
+            # Elm
+            elmPackages.elm
+            elmPackages.elm-format
+            elmPackages.elm-json
+            elmPackages.elm-test
+            elm2nix
+
+            # Build Stuff
+            gnumake
+            modd
+            devd
+          ];
+        };
+      });
+}
diff --git a/shell.nix b/shell.nix
index 194c92c..db84e3d 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,26 +1,3 @@
-{ ... }:
-let
-  sources = import ./nix/sources.nix;
-
-  nixpkgs = import sources.nixpkgs { };
-
-  niv = import sources.niv { };
-in with nixpkgs;
-mkShell {
-  buildInputs = [
-    niv.niv
-    git
-
-    # Elm
-    elmPackages.elm
-    elmPackages.elm-format
-    elmPackages.elm-json
-    elmPackages.elm-test
-    elm2nix
-
-    # Build Stuff
-    gnumake
-    modd
-    devd
-  ];
-}
+(import (fetchTarball https://github.com/edolstra/flake-compat/archive/master.tar.gz) {
+  src = builtins.fetchGit ./.;
+}).shellNix
diff --git a/shell.nix.bak b/shell.nix.bak
new file mode 100644
index 0000000..194c92c
--- /dev/null
+++ b/shell.nix.bak
@@ -0,0 +1,26 @@
+{ ... }:
+let
+  sources = import ./nix/sources.nix;
+
+  nixpkgs = import sources.nixpkgs { };
+
+  niv = import sources.niv { };
+in with nixpkgs;
+mkShell {
+  buildInputs = [
+    niv.niv
+    git
+
+    # Elm
+    elmPackages.elm
+    elmPackages.elm-format
+    elmPackages.elm-json
+    elmPackages.elm-test
+    elm2nix
+
+    # Build Stuff
+    gnumake
+    modd
+    devd
+  ];
+}