diff --git a/.envrc b/.envrc
index 1d953f4..3550a30 100644
--- a/.envrc
+++ b/.envrc
@@ -1 +1 @@
-use nix
+use flake
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..b15beb5
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,68 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "locked": {
+        "lastModified": 1659877975,
+        "narHash": "sha256-zllb8aq3YO3h8B/U0/J1WBgAL8EX5yWf5pMj3G0NAmc=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "c0e246b9b83f637f4681389ecabcb2681b4f3af0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1662019588,
+        "narHash": "sha256-oPEjHKGGVbBXqwwL+UjsveJzghWiWV0n9ogo1X6l4cw=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "2da64a81275b68fdad38af669afeda43d401e94b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "pre-commit-hooks": {
+      "inputs": {
+        "flake-utils": [
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1660830093,
+        "narHash": "sha256-HUhx3a82C7bgp2REdGFeHJdhEAzMGCk3V8xIvfBqg1I=",
+        "owner": "cachix",
+        "repo": "pre-commit-hooks.nix",
+        "rev": "8cb8ea5f1c7bc2984f460587fddd5f2e558f6eb8",
+        "type": "github"
+      },
+      "original": {
+        "owner": "cachix",
+        "ref": "master",
+        "repo": "pre-commit-hooks.nix",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs",
+        "pre-commit-hooks": "pre-commit-hooks"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..a1d46bc
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,38 @@
+{
+  inputs = {
+    flake-utils.url = "github:numtide/flake-utils";
+
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+
+    pre-commit-hooks.url = "github:cachix/pre-commit-hooks.nix/master";
+    pre-commit-hooks.inputs.flake-utils.follows = "flake-utils";
+    pre-commit-hooks.inputs.nixpkgs.follows = "nixpkgs";
+  };
+
+  outputs = { self, flake-utils, nixpkgs, pre-commit-hooks }: flake-utils.lib.eachDefaultSystem (system:
+    let
+      pkgs = import nixpkgs { inherit system; };
+    in
+    {
+      checks = {
+        pre-commit-check = pre-commit-hooks.lib.${system}.run {
+          src = self;
+          hooks = {
+            black.enable = true;
+            nixpkgs-fmt.enable = true;
+            shellcheck.enable = true;
+          };
+        };
+      };
+
+      devShells.default = pkgs.mkShell {
+        buildInputs = (with pkgs; [
+          nixpkgs-fmt
+          black
+          shellcheck
+        ]);
+
+        shellHook = self.checks.${system}.pre-commit-check.shellHook;
+      };
+    });
+}
diff --git a/nix/sources.json b/nix/sources.json
deleted file mode 100644
index 727d9e9..0000000
--- a/nix/sources.json
+++ /dev/null
@@ -1,26 +0,0 @@
-{
-    "nixpkgs": {
-        "branch": "nixos-20.09",
-        "description": "Nix Packages collection",
-        "homepage": "",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "42809feaa9f7474f5566a5c6e8e317e15e39160e",
-        "sha256": "12cnyxx316pwhw069brqsx8v23b10akqlf0vhkilaimsksv7cwgm",
-        "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/42809feaa9f7474f5566a5c6e8e317e15e39160e.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    },
-    "pre-commit-hooks.nix": {
-        "branch": "master",
-        "description": "Seamless integration of https://pre-commit.com git hooks with Nix.",
-        "homepage": "",
-        "owner": "cachix",
-        "repo": "pre-commit-hooks.nix",
-        "rev": "431227b41d0aaa83fabdee6611e145b7d9bd150b",
-        "sha256": "0ff24n8i3mfw0jw5r5lsgvbahmh88zhi3qsk9yxrb8x82jprgzsy",
-        "type": "tarball",
-        "url": "https://github.com/cachix/pre-commit-hooks.nix/archive/431227b41d0aaa83fabdee6611e145b7d9bd150b.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
-    }
-}
diff --git a/nix/sources.nix b/nix/sources.nix
deleted file mode 100644
index f614e68..0000000
--- a/nix/sources.nix
+++ /dev/null
@@ -1,149 +0,0 @@
-# This file has been generated by Niv.
-let
-  #
-  # The fetchers. fetch_<type> fetches specs of type <type>.
-  #
-
-  fetch_file = pkgs: spec:
-    if spec.builtin or true then
-      builtins_fetchurl { inherit (spec) url sha256; }
-    else
-      pkgs.fetchurl { inherit (spec) url sha256; };
-
-  fetch_tarball = pkgs: name: spec:
-    let
-      ok = str: ! builtins.isNull (builtins.match "[a-zA-Z0-9+-._?=]" str);
-      # sanitize the name, though nix will still fail if name starts with period
-      name' = stringAsChars (x: if ! ok x then "-" else x) "${name}-src";
-    in
-    if spec.builtin or true then
-      builtins_fetchTarball { name = name'; inherit (spec) url sha256; }
-    else
-      pkgs.fetchzip { name = name'; inherit (spec) url sha256; };
-
-  fetch_git = spec:
-    builtins.fetchGit { url = spec.repo; inherit (spec) rev ref; };
-
-  fetch_local = spec: spec.path;
-
-  fetch_builtin-tarball = name: throw
-    ''[${name}] The niv type "builtin-tarball" is deprecated. You should instead use `builtin = true`.
-        $ niv modify ${name} -a type=tarball -a builtin=true'';
-
-  fetch_builtin-url = name: throw
-    ''[${name}] The niv type "builtin-url" will soon be deprecated. You should instead use `builtin = true`.
-        $ niv modify ${name} -a type=file -a builtin=true'';
-
-  #
-  # Various helpers
-  #
-
-  # The set of packages used when specs are fetched using non-builtins.
-  mkPkgs = sources:
-    let
-      sourcesNixpkgs =
-        import (builtins_fetchTarball { inherit (sources.nixpkgs) url sha256; }) { };
-      hasNixpkgsPath = builtins.any (x: x.prefix == "nixpkgs") builtins.nixPath;
-      hasThisAsNixpkgsPath = <nixpkgs> == ./.;
-    in
-    if builtins.hasAttr "nixpkgs" sources
-    then sourcesNixpkgs
-    else if hasNixpkgsPath && ! hasThisAsNixpkgsPath then
-      import <nixpkgs> { }
-    else
-      abort
-        ''
-          Please specify either <nixpkgs> (through -I or NIX_PATH=nixpkgs=...) or
-          add a package called "nixpkgs" to your sources.json.
-        '';
-
-  # The actual fetching function.
-  fetch = pkgs: name: spec:
-
-    if ! builtins.hasAttr "type" spec then
-      abort "ERROR: niv spec ${name} does not have a 'type' attribute"
-    else if spec.type == "file" then fetch_file pkgs spec
-    else if spec.type == "tarball" then fetch_tarball pkgs name spec
-    else if spec.type == "git" then fetch_git spec
-    else if spec.type == "local" then fetch_local spec
-    else if spec.type == "builtin-tarball" then fetch_builtin-tarball name
-    else if spec.type == "builtin-url" then fetch_builtin-url name
-    else
-      abort "ERROR: niv spec ${name} has unknown type ${builtins.toJSON spec.type}";
-
-  # If the environment variable NIV_OVERRIDE_${name} is set, then use
-  # the path directly as opposed to the fetched source.
-  replace = name: drv:
-    let
-      saneName = stringAsChars (c: if isNull (builtins.match "[a-zA-Z0-9]" c) then "_" else c) name;
-      ersatz = builtins.getEnv "NIV_OVERRIDE_${saneName}";
-    in
-    if ersatz == "" then drv else ersatz;
-
-  # Ports of functions for older nix versions
-
-  # a Nix version of mapAttrs if the built-in doesn't exist
-  mapAttrs = builtins.mapAttrs or (
-    f: set: with builtins;
-    listToAttrs (map (attr: { name = attr; value = f attr set.${attr}; }) (attrNames set))
-  );
-
-  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/lists.nix#L295
-  range = first: last: if first > last then [ ] else builtins.genList (n: first + n) (last - first + 1);
-
-  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L257
-  stringToCharacters = s: map (p: builtins.substring p 1 s) (range 0 (builtins.stringLength s - 1));
-
-  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L269
-  stringAsChars = f: s: concatStrings (map f (stringToCharacters s));
-  concatStrings = builtins.concatStringsSep "";
-
-  # fetchTarball version that is compatible between all the versions of Nix
-  builtins_fetchTarball = { url, name, sha256 }@attrs:
-    let
-      inherit (builtins) lessThan nixVersion fetchTarball;
-    in
-    if lessThan nixVersion "1.12" then
-      fetchTarball { inherit name url; }
-    else
-      fetchTarball attrs;
-
-  # fetchurl version that is compatible between all the versions of Nix
-  builtins_fetchurl = { url, sha256 }@attrs:
-    let
-      inherit (builtins) lessThan nixVersion fetchurl;
-    in
-    if lessThan nixVersion "1.12" then
-      fetchurl { inherit url; }
-    else
-      fetchurl attrs;
-
-  # Create the final "sources" from the config
-  mkSources = config:
-    mapAttrs
-      (
-        name: spec:
-          if builtins.hasAttr "outPath" spec
-          then
-            abort
-              "The values in sources.json should not have an 'outPath' attribute"
-          else
-            spec // { outPath = replace name (fetch config.pkgs name spec); }
-      )
-      config.sources;
-
-  # The "config" used by the fetchers
-  mkConfig =
-    { sourcesFile ? if builtins.pathExists ./sources.json then ./sources.json else null
-    , sources ? if isNull sourcesFile then { } else builtins.fromJSON (builtins.readFile sourcesFile)
-    , pkgs ? mkPkgs sources
-    }: rec {
-      # The sources, i.e. the attribute set of spec name to spec
-      inherit sources;
-
-      # The "pkgs" (evaluated nixpkgs) to use for e.g. non-builtin fetchers
-      inherit pkgs;
-    };
-
-in
-mkSources (mkConfig { }) // { __functor = _: settings: mkSources (mkConfig settings); }
diff --git a/pre-commit.nix b/pre-commit.nix
deleted file mode 100644
index c730bf6..0000000
--- a/pre-commit.nix
+++ /dev/null
@@ -1,11 +0,0 @@
-let
-  nix-pre-commit-hooks = import (import ./nix/sources.nix)."pre-commit-hooks.nix";
-in
-nix-pre-commit-hooks.run {
-  src = ./.;
-  hooks = {
-    black.enable = true;
-    nixpkgs-fmt.enable = true;
-    shellcheck.enable = true;
-  };
-}
diff --git a/shell.nix b/shell.nix
deleted file mode 100644
index 9ed1eda..0000000
--- a/shell.nix
+++ /dev/null
@@ -1,13 +0,0 @@
-let
-  sources = import ./nix/sources.nix;
-  pkgs = import sources.nixpkgs { };
-in
-pkgs.mkShell {
-  nativeBuildInputs = with pkgs; [
-    git
-    nixpkgs-fmt
-  ];
-  shellHook = ''
-    ${(import ./pre-commit.nix).shellHook}
-  '';
-}