diff --git a/core/WORKSPACE b/core/WORKSPACE
index c992e4734..ddfa59e74 100644
--- a/core/WORKSPACE
+++ b/core/WORKSPACE
@@ -47,7 +47,7 @@ nixpkgs_local_repository(
     nix_file_content = "import ./nixpkgs.nix",
     nix_file_deps = [
         "//:nixpkgs.nix",
-        "//:nixpkgs.json",
+        "//:flake.lock",
     ],
 )
 
@@ -72,7 +72,7 @@ nixpkgs_package(
 nixpkgs_package(
     name = "expr-test",
     nix_file_content = "let pkgs = import <nixpkgs> { config = {}; overlays = []; }; in pkgs.hello",
-    nix_file_deps = ["//:nixpkgs.json"],
+    nix_file_deps = ["//:flake.lock"],
     # Deliberately not @nixpkgs, to test whether explict file works.
     repositories = {"nixpkgs": "//:nixpkgs.nix"},
 )
@@ -141,7 +141,7 @@ nixpkgs_package(
     attribute_path = "hello",
     nix_file = "//tests:relative_imports.nix",
     nix_file_deps = [
-        "//:nixpkgs.json",
+        "//:flake.lock",
         "//:nixpkgs.nix",
         "//tests:relative_imports/nixpkgs.nix",
     ],
@@ -155,7 +155,7 @@ nixpkgs_package(
     attribute_path = "",
     nix_file_content = """let pkgs = import <nixpkgs> { config = {}; overlays = []; }; in pkgs.writeText "foo" "bar" """,
     nix_file_deps = [
-        "//:nixpkgs.json",
+        "//:flake.lock",
         "//:nixpkgs.nix",
         "//tests:relative_imports/nixpkgs.nix",
     ],
diff --git a/core/docs/dependencies_2.bzl b/core/docs/dependencies_2.bzl
index 37cf1be5e..ca6c38cae 100644
--- a/core/docs/dependencies_2.bzl
+++ b/core/docs/dependencies_2.bzl
@@ -17,7 +17,7 @@ def docs_dependencies_2():
     nixpkgs_local_repository(
         name = "nixpkgs",
         nix_file = "@rules_nixpkgs_core//:nixpkgs.nix",
-        nix_file_deps = ["@rules_nixpkgs_core//:nixpkgs.json"],
+        nix_file_deps = ["@rules_nixpkgs_core//:flake.lock"],
     )
 
     rules_sh_dependencies()
diff --git a/core/flake.lock b/core/flake.lock
new file mode 120000
index 000000000..1985b6556
--- /dev/null
+++ b/core/flake.lock
@@ -0,0 +1 @@
+../flake.lock
\ No newline at end of file
diff --git a/core/nixpkgs.json b/core/nixpkgs.json
deleted file mode 100644
index 524887447..000000000
--- a/core/nixpkgs.json
+++ /dev/null
@@ -1,7 +0,0 @@
-{
-  "owner": "NixOS",
-  "repo": "nixpkgs",
-  "branch": "22.05",
-  "rev": "ce6aa13369b667ac2542593170993504932eb836",
-  "sha256": "0d643wp3l77hv2pmg2fi7vyxn4rwy0iyr8djcw1h5x72315ck9ik"
-}
diff --git a/core/nixpkgs.nix b/core/nixpkgs.nix
index 120a30c38..5b3a2a3b8 100644
--- a/core/nixpkgs.nix
+++ b/core/nixpkgs.nix
@@ -1,9 +1,11 @@
 let
-  # nixpkgs 21.11
-  spec = builtins.fromJSON (builtins.readFile ./nixpkgs.json);
-  nixpkgs = fetchTarball {
-    url = "https://github.com/${spec.owner}/${spec.repo}/archive/${spec.rev}.tar.gz";
-    sha256 = spec.sha256;
-  };
+  lock = builtins.fromJSON (builtins.readFile ./flake.lock);
+  src = lock.nodes.nixpkgs.locked;
+  nixpkgs =
+    assert src.type == "github";
+    fetchTarball {
+      url = "https://github.com/${src.owner}/${src.repo}/archive/${src.rev}.tar.gz";
+      sha256 = src.narHash;
+    };
 in
 import nixpkgs
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 000000000..9ab1863d3
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,60 @@
+{
+  "nodes": {
+    "flake-compat": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1650374568,
+        "narHash": "sha256-Z+s0J8/r907g149rllvwhb4pKi8Wam5ij0st8PwAh+E=",
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "rev": "b4a34015c698c7793d592d66adbab377907a2be8",
+        "type": "github"
+      },
+      "original": {
+        "owner": "edolstra",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
+    "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": 1662099760,
+        "narHash": "sha256-MdZLCTJPeHi/9fg6R9fiunyDwP3XHJqDd51zWWz9px0=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "67e45078141102f45eff1589a831aeaa3182b41e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-22.05",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-compat": "flake-compat",
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 000000000..6d28fccec
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,21 @@
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-22.05";
+    flake-compat = {
+      url = github:edolstra/flake-compat;
+      flake = false;
+    };
+    flake-utils.url = github:numtide/flake-utils;
+  };
+  outputs = { nixpkgs, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+      in
+      {
+        devShells.default = with pkgs; mkShell {
+          name = "rules_nixpkgs_shell";
+          packages = [ bazel_5 bazel-buildtools cacert gcc nix git ];
+        };
+      });
+}
diff --git a/shell.nix b/shell.nix
index 59c9d0fd0..a8e628cca 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,11 +1,11 @@
-{ pkgs ? import ./core/nixpkgs.nix {
-  config = { };
-  overlays = [ ];
-} }:
+(import
+  (
+    let lock = builtins.fromJSON (builtins.readFile ./flake.lock); in
+    fetchTarball {
+      url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+      sha256 = lock.nodes.flake-compat.locked.narHash;
+    }
+  )
+  { src = ./.; }
+).shellNix
 
-with pkgs;
-
-mkShell {
-  name = "rules_nixpkgs_shell";
-  packages = [ bazel_5 bazel-buildtools cacert gcc nix git ];
-}