diff --git a/shell.nix b/shell.nix
index 2ae043c..3963630 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,94 +1,6 @@
-{ command ? "bash --noprofile --norc" }:
 # If you're on NixOS, use me! `nix-shell --pure`.
-with import (fetchTarball {
-  # nixpkgs 23.05 as of 2023/07/19
-  url = "https://github.com/NixOS/nixpkgs/archive/2fadc2426928c844054cd28fabe231ff26a70715.tar.gz";
-  sha256 = "sha256:06hpcqhaaqvd5gjcz2ps9lz6q2sf5fwgl5rwllpyl9x4g5g95ahv";
-}) {};
+{ sources ? import third_party/nix/sources.nix }:
 let
-  wrapper = pkgs.writeScript "wrapper.sh"
-  ''
-    # Fancy colorful PS1 to make people notice easily they're in the Monogon Nix shell.
-    PS1='\[\033]0;\u/monogon:\w\007\]'
-    if type -P dircolors >/dev/null ; then
-      PS1+='\[\033[01;35m\]\u/monogon\[\033[01;36m\] \w \$\[\033[00m\] '
-    fi
-    export PS1
-
-    # Use Nix-provided cert store.
-    export NIX_SSL_CERT_FILE="${cacert}/etc/ssl/certs/ca-bundle.crt"
-    export SSL_CERT_FILE="${cacert}/etc/ssl/certs/ca-bundle.crt"
-
-    # Let some downstream machinery know we're on NixOS. This is used mostly to
-    # work around Bazel/NixOS interactions.
-    export MONOGON_NIXOS=yep
-
-    # Convince rules_go to use /bin/bash and not a NixOS store bash which has
-    # no idea how to resolve other things in the nix store once PATH is
-    # stripped by (host_)action_env.
-    export BAZEL_SH=/bin/bash
-
-    # Allow passing a custom command via env since nix-shell doesn't support
-    # this yet: https://github.com/NixOS/nix/issues/534
-    if [ ! -n "$COMMAND" ]; then
-        COMMAND="bash --noprofile --norc"
-    fi
-    exec $COMMAND
-  '';
+    pkgs = import sources.nixpkgs {};
 in
-(pkgs.buildFHSUserEnv {
-  name = "monogon-nix";
-  targetPkgs = pkgs: with pkgs; [
-    git
-    buildifier
-    (stdenv.mkDerivation {
-      name = "bazel";
-      src = builtins.fetchurl  {
-        url = https://github.com/bazelbuild/bazel/releases/download/5.4.0/bazel-5.4.0-linux-x86_64;
-        sha256 = "1w58m1brwjfwsv48fmd66inry67m4vgb3bwvwmamhdv099v183jg";
-      };
-      unpackPhase = ''
-        true
-      '';
-      buildPhase = ''
-        mkdir -p $out/bin
-        cp $src $out/bin/.bazel-inner
-        chmod +x $out/bin/.bazel-inner
-
-        cat > $out/bin/bazel <<EOF
-        #!/usr/bin/bash
-        export BAZEL_REAL=$out/bin/.bazel-inner
-        function get_workspace_root() {
-          workspace_dir="\''${PWD}"
-          while [[ "\''${workspace_dir}" != / ]]; do
-            if [[ -e "\''${workspace_dir}/WORKSPACE" || -e "\''${workspace_dir}/WORKSPACE.bazel" ]]; then
-              readonly workspace_dir
-              return
-            fi
-            workspace_dir="$(dirname "\''${workspace_dir}")"
-          done
-          readonly workspace_dir=""
-        }
-
-        get_workspace_root
-        readonly wrapper="\''${workspace_dir}/tools/bazel"
-        if [ -f "\''${wrapper}" ]; then
-          exec -a "\$0" "\''${wrapper}" "\$@"
-        fi
-        exec -a "\$0" "\''${BAZEL_REAL}" "\$@"
-        EOF
-        chmod +x $out/bin/bazel
-      '';
-      dontStrip = true;
-    })
-    zlib
-    curl
-    gcc
-    binutils
-    openjdk11
-    patch
-    python3
-  ];
-  runScript = wrapper;
-}).env
-
+(import third_party/nix/env.nix { inherit pkgs; }).env