diff --git a/default.nix b/default.nix
index fd05850..5969b92 100644
--- a/default.nix
+++ b/default.nix
@@ -1,67 +1,6 @@
-{ pkgs ? import ./nix {
-    overlays = [ (import ./nix/overlay.nix) ];
-  }
-}:
-
-let
-  inherit (pkgs) lib;
-
-  pkg = pkgs.rustPlatform.buildRustPackage {
-    name = "ofborg";
-    src = pkgs.nix-gitignore.gitignoreSource [ ] ./.;
-
-    nativeBuildInputs = with pkgs; [
-      pkgconfig
-      pkgs.rustPackages.clippy
-    ];
-
-    buildInputs = with pkgs; [
-      openssl
-    ] ++ lib.optionals pkgs.stdenv.isDarwin (with pkgs; [
-      darwin.apple_sdk.frameworks.Security
-      darwin.apple_sdk.frameworks.CoreFoundation
-    ]);
-
-    preBuild = ''
-      cargo clippy
-    '';
-
-    doCheck = false; # Tests require access to a /nix/ and a nix daemon
-    checkInputs = with pkgs; [
-      nix
-    ];
-
-    cargoLock = {
-      lockFile = ./Cargo.lock;
-      outputHashes = {
-        "hubcaps-0.3.16" = "sha256-/BFXGccu27K8heK4IL7JnS/U7zatTk9wRybhtxppADM=";
-      };
-    };
-  };
-in
-
-{
-  inherit pkg;
-
-  ofborg.rs = pkgs.runCommand "ofborg-rs-symlink-compat" { src = pkg; } ''
-    mkdir -p $out/bin
-    for f in $(find $src -type f); do
-      bn=$(basename "$f")
-      ln -s "$f" "$out/bin/$bn"
-
-      # Rust 1.n? or Cargo  starting outputting bins with dashes
-      # instead of underscores ... breaking all the callers.
-      if echo "$bn" | grep -q "-"; then
-        ln -s "$f" "$out/bin/$(echo "$bn" | tr '-' '_')"
-      fi
-    done
-
-    test -e $out/bin/builder
-    test -e $out/bin/github_comment_filter
-    test -e $out/bin/github_comment_poster
-    test -e $out/bin/log_message_collector
-    test -e $out/bin/evaluation_filter
-  '';
-
-  ofborg.php = import ./php { inherit pkgs; };
-}
+(import
+  (fetchTarball {
+    url = "https://github.com/edolstra/flake-compat/archive/99f1c2157fba4bfe6211a321fd0ee43199025dbf.tar.gz";
+    sha256 = "0x2jn3vrawwv9xp15674wjz9pixwjyj3j771izayl962zziivbx2";
+  })
+  { src = ./.; }).defaultNix.packages.${builtins.currentSystem}
diff --git a/flake.nix b/flake.nix
index 55d512f..582d7b8 100644
--- a/flake.nix
+++ b/flake.nix
@@ -13,16 +13,12 @@
       forAllSystems = f: nixpkgs.lib.genAttrs supportedSystems (system: f system);
     in
     {
-      # TODO(cole-h): see if we still need these overlays
-      # overlays.default = import ./nix/overlay.nix;
-      overlays.default = _: _: { };
-
+      devShell = forAllSystems (system: inputs.self.devShells.${system}.default);
       devShells = forAllSystems
         (system:
           let
             pkgs = import nixpkgs {
               inherit system;
-              overlays = [ self.overlays.default ];
             };
 
             phpEnv = pkgs.mkShell {
@@ -87,7 +83,6 @@
         let
           pkgs = import nixpkgs {
             inherit system;
-            overlays = [ self.overlays.default ];
           };
 
           pkg = pkgs.rustPlatform.buildRustPackage {
@@ -124,7 +119,7 @@
           };
 
         in
-        rec {
+        {
           inherit pkg;
 
           ofborg.rs = pkgs.runCommand "ofborg-rs-symlink-compat" { src = pkg; } ''
diff --git a/nix/default.nix b/nix/default.nix
deleted file mode 100644
index 286ea32..0000000
--- a/nix/default.nix
+++ /dev/null
@@ -1,25 +0,0 @@
-let
-  hostpkgs = import <nixpkgs> {};
-
-  srcDef = builtins.fromJSON (builtins.readFile ./nixpkgs.json);
-
-  inherit (hostpkgs) fetchFromGitHub fetchpatch fetchurl;
-in import (hostpkgs.stdenv.mkDerivation {
-  name = "ofborg-nixpkgs-${builtins.substring 0 10 srcDef.rev}";
-  phases = [ "unpackPhase" "patchPhase" "moveToOut" ];
-
-  src = fetchFromGitHub {
-    owner = "NixOS";
-    repo = "nixpkgs";
-    inherit (srcDef) rev sha256;
-  };
-
-  patches = [
-  ];
-
-  moveToOut = ''
-    root=$(pwd)
-    cd ..
-    mv "$root" $out
-  '';
-})
diff --git a/nix/nixpkgs.json b/nix/nixpkgs.json
deleted file mode 100644
index 9cd13ae..0000000
--- a/nix/nixpkgs.json
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-  "url": "https://github.com/nixos/nixpkgs.git",
-  "rev": "43b394b98e352562a6ea63db387b9fbdd858727f",
-  "date": "2021-11-11T14:00:02+01:00",
-  "path": "/nix/store/465a6kmjj22qyvhcyrjgm0azcnsm35f5-nixpkgs",
-  "sha256": "1r2s8hyhdlf2js1hlmgmmdkhb2bi0dyf9yil0xig5vz7g2ac2l47",
-  "fetchLFS": false,
-  "fetchSubmodules": false,
-  "deepClone": false,
-  "leaveDotGit": false
-}
diff --git a/nix/overlay.nix b/nix/overlay.nix
deleted file mode 100644
index fe17a56..0000000
--- a/nix/overlay.nix
+++ /dev/null
@@ -1,14 +0,0 @@
-(self: super:
-{
-  defaultCrateOverrides = super.defaultCrateOverrides // {
-    ofborg = attrs: {
-      buildInputs = with self.darwin.apple_sdk.frameworks;
-        super.lib.optional super.stdenv.isDarwin Security;
-    };
-    ofborg-simple-build = attrs: {
-      buildInputs = with self.darwin.apple_sdk.frameworks;
-        super.lib.optional super.stdenv.isDarwin Security;
-    };
-  };
-})
-
diff --git a/nix/update-nixpkgs.sh b/nix/update-nixpkgs.sh
deleted file mode 100755
index bcc9e14..0000000
--- a/nix/update-nixpkgs.sh
+++ /dev/null
@@ -1,5 +0,0 @@
-#!/usr/bin/env nix-shell
-#!nix-shell -i bash -p nix-prefetch-git
-
-nix-prefetch-git https://github.com/nixos/nixpkgs.git \
-                 --rev refs/heads/nixos-unstable-small > ./nix/nixpkgs.json
diff --git a/release.nix b/release.nix
deleted file mode 100644
index c43b03f..0000000
--- a/release.nix
+++ /dev/null
@@ -1,83 +0,0 @@
-{ nixpkgs ? ./nix
-, supportedSystems ? [ "x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin" ]
-}:
-let
-  pkgs = import nixpkgs {
-    overlays = [ (import ./nix/overlay.nix) ];
-  };
-  inherit (pkgs) lib;
-
-  # An attrset of borgpkgs per supportedSystem:
-  #
-  # {
-  #   "x86_64-linux" = ...
-  #   "x86_64-darwin" = ...
-  # }
-  borgpkgs-per-arch = builtins.foldl'
-    (collector: system:
-      collector // {
-        "${system}" = import ./. {
-          pkgs = import nixpkgs {
-            inherit system;
-            overlays = [
-              (import ./nix/overlay.nix)
-            ];
-          };
-        };
-      }
-    )
-    { }
-    supportedSystems;
-
-  attrForSystem = system: attrpath:
-    if borgpkgs-per-arch ? "${system}"
-    then
-      (
-        let
-          borgpkgs = borgpkgs-per-arch."${system}";
-        in
-        if lib.hasAttrByPath attrpath borgpkgs
-        then
-          lib.setAttrByPath
-            (attrpath ++ [ system ])
-            (lib.attrByPath attrpath "bogus" borgpkgs)
-        else throw "Failed to find ${toString attrpath} for ${system} in borgpkgs"
-      )
-    else throw "No such system ${system}";
-
-  attrsForAllSystems = path:
-    builtins.foldl'
-      (collector: system:
-        lib.recursiveUpdate collector (attrForSystem system path)
-      )
-      { }
-      supportedSystems;
-
-  merge = attrsets:
-    builtins.foldl'
-      (collector: set: lib.recursiveUpdate set collector)
-      { }
-      attrsets;
-
-  x8664LinuxOnly = path:
-    (attrForSystem "x86_64-linux" path);
-
-  jobs = merge [
-    (attrsForAllSystems [ "ofborg" "rs" ])
-
-    (x8664LinuxOnly [ "ofborg" "php" ])
-  ];
-in
-jobs // {
-  release = pkgs.releaseTools.aggregate {
-    name = "release";
-    meta.description = "Release-critical builds for OfBorg infrastructure";
-    constituents = [
-      jobs.ofborg.rs.x86_64-linux
-      jobs.ofborg.rs.x86_64-darwin
-      jobs.ofborg.rs.aarch64-darwin
-      jobs.ofborg.rs.aarch64-linux
-      jobs.ofborg.php.x86_64-linux
-    ];
-  };
-}
diff --git a/shell.nix b/shell.nix
index 6dcb5c8..4f7af74 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,71 +1,6 @@
-{ pkgs ? import ./nix {
-  overlays = [
-    (import ./nix/overlay.nix)
-  ];
-} }:
-
-let
-  inherit (pkgs) stdenv lib;
-
-  phpEnv = stdenv.mkDerivation rec {
-    name = "gh-event-forwarder";
-    src = null;
-    buildInputs = with pkgs; [
-      nix-prefetch-git
-      php
-      phpPackages.composer
-      git
-      php
-      curl
-      bash
-    ];
-
-    # HISTFILE = "${src}/.bash_hist";
-  };
-
-  rustEnv = stdenv.mkDerivation {
-    name = "gh-event-forwarder";
-    nativeBuildInputs = with pkgs; [
-      nix # so in --pure mode we actually find the "correct" nix
-      bash
-      nix-prefetch-git
-      rustc
-      cargo
-      clippy
-      rustfmt
-      pkg-config
-      git
-    ];
-    buildInputs = with pkgs; [
-      openssl
-    ] ++ lib.optionals stdenv.isDarwin [ darwin.Security libiconv ];
-
-    postHook = ''
-      checkPhase() (
-          cd "${builtins.toString ./.}/ofborg"
-          set -x
-          cargo fmt
-          git diff --exit-code
-          cargofmtexit=$?
-  
-          cargo clippy
-          cargoclippyexit=$?
-  
-
-          cargo build && cargo test
-          cargotestexit=$?
-
-          sum=$((cargofmtexit + cargoclippyexit + cargotestexit))
-          exit $sum
-      )
-    '';
-
-    HISTFILE = "${toString ./.}/.bash_hist";
-    RUSTFLAGS = "-D warnings";
-    RUST_BACKTRACE = "1";
-    RUST_LOG = "ofborg=debug";
-    NIX_PATH = "nixpkgs=${pkgs.path}";
-    passthru.phpEnv = phpEnv;
-  };
-
-in rustEnv
+(import
+  (fetchTarball {
+    url = "https://github.com/edolstra/flake-compat/archive/99f1c2157fba4bfe6211a321fd0ee43199025dbf.tar.gz";
+    sha256 = "0x2jn3vrawwv9xp15674wjz9pixwjyj3j771izayl962zziivbx2";
+  })
+  { src = ./.; }).shellNix