diff --git a/cabal.project b/cabal.project
index f3c121f8..fda6f25f 100644
--- a/cabal.project
+++ b/cabal.project
@@ -1,17 +1,13 @@
 packages:
-  account/backend/
   account/types/
   aeson-orphans/
-  backend/
   beam/db/
   beam/orphans/
-  beam/task/backend/
   beam/task/types/
   common/
   email/
   email/mime-mail-orphans/
   frontend/
-  iv/backend/
   iv/common/
   notify-listen/notify-listen/
   notify-listen/notify-listen-beam/
@@ -22,10 +18,21 @@ packages:
   signed-data/signed-data/
   signed-data/signed-data-clientsession/
   test/
+
   widgets/
 
+if (!os(ghcjs))
+  packages:
+    account/backend/
+    backend/
+    beam/task/backend/
+    iv/backend/
+
 allow-newer:
   postgresql-lo-stream:*,
   vessel:*,
   aeson-gadt-th:*,
+  attoparsec,
 
+allow-older:
+  postgresql-simple,
diff --git a/default.nix b/default.nix
index 456c01ac..0178f74d 100644
--- a/default.nix
+++ b/default.nix
@@ -1,16 +1,9 @@
-{ obelisk ? import ./dep/obelisk (builtins.removeAttrs args ["pkgs" "inNixShell"] // { useGHC810 = true; })
-, pkgs ? obelisk.nixpkgs
+{ obelisk ? import ./dep/obelisk (builtins.removeAttrs args ["pkgs" "inNixShell"])
+, pkgs ? obelisk.pkgs
 , ... } @ args:
 
 let
-  reflex-platform = obelisk.reflex-platform;
-  inherit (pkgs) lib;
-  haskellLib = pkgs.haskell.lib;
-  repos = pkgs.thunkSet ./dep;
-
-  # Some dependency thunks needed
-  dep = import ./dep reflex-platform.hackGet;
-  #TODO: Consider whether to prefer using thunkSet here.
+  nix-thunk = import ./dep/nix-thunk { inherit pkgs; };
 
   # Local packages. We override them below so that other packages can use them.
   rhyolitePackages = {
@@ -41,8 +34,12 @@ let
     signed-data-clientsession = ./signed-data/signed-data-clientsession;
   };
 
+  repos = nix-thunk.mapSubdirectories
+    nix-thunk.thunkSource
+    ./dep;
+
   # srcs used for overrides
-  overrideSrcs = rhyolitePackages // {
+  haskellPackageSources = rhyolitePackages // {
     beam-sqlite = repos.beam + "/beam-sqlite";
     beam-core = repos.beam + "/beam-core";
     beam-postgres = repos.beam + "/beam-postgres";
@@ -61,7 +58,7 @@ let
     postgresql-simple = repos.postgresql-simple;
     postgresql-simple-interpolate = repos.postgresql-simple-interpolate;
 
-    # Newer versions than those in reflex-platform
+    # Newer versions than those in Reflex Platform
     gargoyle = repos.gargoyle + "/gargoyle";
     gargoyle-postgresql = repos.gargoyle + "/gargoyle-postgresql";
     gargoyle-postgresql-connect = repos.gargoyle + "/gargoyle-postgresql-connect";
@@ -74,78 +71,24 @@ let
     vessel = repos.vessel;
   };
 
-  # You can use these manually if you don’t want to use rhyolite.project.
-  # It will be needed if you need to combine with multiple overrides.
-  haskellOverrides = lib.foldr lib.composeExtensions (_: _: {}) [
-    (self: super: lib.mapAttrs (name: path: self.callCabal2nix name path {}) overrideSrcs)
-    (self: super: {
-      frontend = super.frontend.override {
-        obelisk-executable-config-lookup = self.obelisk-executable-config-lookup;
-      };
-      beam-automigrate = haskellLib.doJailbreak super.beam-automigrate;
-      beam-postgres = haskellLib.dontCheck super.beam-postgres;
-      beam-migrate = haskellLib.dontCheck super.beam-migrate;
-      bytestring-trie = haskellLib.dontCheck super.bytestring-trie;
-      gargoyle-postgresql-nix = haskellLib.overrideCabal super.gargoyle-postgresql-nix {
-        librarySystemDepends = [ pkgs.postgresql ];
-      };
-      postgresql-simple = haskellLib.dontCheck super.postgresql-simple;
-      validation = haskellLib.dontCheck super.validation;
-
-      postgresql-lo-stream = haskellLib.doJailbreak (self.callHackageDirect {
-        pkg = "postgresql-lo-stream";
-        ver = "0.1.1.1";
-        sha256 = "0ifr6i6vygckj2nikv7k7yqia495gnn27pq6viasckmmh6zx6gwi";
-      } {});
-
-      monad-logger-extras = self.callHackageDirect {
-        pkg = "monad-logger-extras";
-        ver = "0.1.1.1";
-        sha256 = "17dr2jwg1ig1gd4hw7160vf3l5jcx5p79b2lz7k17f6v4ygx3vbz";
-      } {};
-      monoid-subclasses = self.callHackageDirect {
-        pkg = "monoid-subclasses";
-        ver = "1.1";
-        sha256 = "02ggjcwjdjh6cmy7zaji5mcmnq140sp33cg9rvwjgply6hkddrvb";
-      } {};
-      HaskellNet = self.callHackage "HaskellNet" "0.6" {};
-      HaskellNet-SSL = self.callHackage "HaskellNet-SSL" "0.3.4.4" {};
-
-      base-orphans = self.callHackageDirect {
-        pkg = "base-orphans";
-        ver = "0.8.6";
-        sha256 = "sha256:17hplm1mgw65jbszg5z4vqk4i24ilxv8mbszr3s8lhpll5naik26";
-      } {};
-
-      # 'locale' is broken on nix darwin which is required by postgres 'initdb'
-      rhyolite-beam-task-worker-backend = if pkgs.stdenv.hostPlatform.isDarwin
-      then
-        haskellLib.dontCheck super.rhyolite-beam-task-worker-backend
-      else
-        super.rhyolite-beam-task-worker-backend;
-    })
-  ];
-
 in obelisk // {
 
-  inherit haskellOverrides;
-
-  rhyolitePackages = haskellPackages: builtins.intersectAttrs rhyolitePackages (haskellPackages.extend haskellOverrides);
-
-  haskellPackageSources = overrideSrcs;
+  inherit rhyolitePackages haskellPackageSources;
 
   # Function similar to obelisk.project that handles overrides for you.
   project = base: projectDefinition:
     obelisk.project base ({...}@args:
       let def = projectDefinition args;
       in def // {
-        overrides = lib.composeExtensions haskellOverrides (def.overrides or (_: _: {}));
+        inputThunks = haskellPackageSources // def.inputThunks or {};
       });
 
   # Used to build this project. Should only be needed by CI, devs.
-  proj = obelisk.reflex-platform.project ({ pkgs, ... }@args: {
-    overrides = haskellOverrides;
-    packages = rhyolitePackages;
+  proj = obelisk.project {} ({ pkgs, ... }@args: {
+    name = "rhyolite-test-project";
+    src = ./.;
+    inputThunks = builtins.attrValues haskellPackageSources;
+    extraArgs = {};
     shells = rec {
       ghc = builtins.attrNames rhyolitePackages;
       ghcjs = [
diff --git a/dep/nix-thunk/default.nix b/dep/nix-thunk/default.nix
new file mode 100644
index 00000000..2b4d4ab1
--- /dev/null
+++ b/dep/nix-thunk/default.nix
@@ -0,0 +1,2 @@
+# DO NOT HAND-EDIT THIS FILE
+import (import ./thunk.nix)
\ No newline at end of file
diff --git a/dep/nix-thunk/github.json b/dep/nix-thunk/github.json
new file mode 100644
index 00000000..212315fe
--- /dev/null
+++ b/dep/nix-thunk/github.json
@@ -0,0 +1,7 @@
+{
+  "owner": "obsidiansystems",
+  "repo": "nix-thunk",
+  "private": false,
+  "rev": "3ce834d514c77bcfd889bd07cb69c1d65172d651",
+  "sha256": "1rvpm0wh62kzaii3d75ijgl8vr2sg3p0ifv2swjccwv3rv380vwg"
+}
diff --git a/dep/nix-thunk/thunk.nix b/dep/nix-thunk/thunk.nix
new file mode 100644
index 00000000..20f2d28c
--- /dev/null
+++ b/dep/nix-thunk/thunk.nix
@@ -0,0 +1,12 @@
+# DO NOT HAND-EDIT THIS FILE
+let fetch = { private ? false, fetchSubmodules ? false, owner, repo, rev, sha256, ... }:
+  if !fetchSubmodules && !private then builtins.fetchTarball {
+    url = "https://github.com/${owner}/${repo}/archive/${rev}.tar.gz"; inherit sha256;
+  } else (import (builtins.fetchTarball {
+  url = "https://github.com/NixOS/nixpkgs/archive/3aad50c30c826430b0270fcf8264c8c41b005403.tar.gz";
+  sha256 = "0xwqsf08sywd23x0xvw4c4ghq0l28w2ki22h0bdn766i16z9q2gr";
+}) {}).fetchFromGitHub {
+    inherit owner repo rev sha256 fetchSubmodules private;
+  };
+  json = builtins.fromJSON (builtins.readFile ./github.json);
+in fetch json
\ No newline at end of file
diff --git a/dep/obelisk/github.json b/dep/obelisk/github.json
index f32e7a27..52ed549a 100644
--- a/dep/obelisk/github.json
+++ b/dep/obelisk/github.json
@@ -1,8 +1,8 @@
 {
   "owner": "obsidiansystems",
   "repo": "obelisk",
-  "branch": "pzp",
+  "branch": "haskell.nix",
   "private": false,
-  "rev": "db78e4d4c20d9d51f90e00e5d9a0d5e77c0baf82",
-  "sha256": "1yxwvfdlv3ii17jrd3w2yiiza26d400b35x04gmpv209xk26yz3h"
+  "rev": "d817702be87bb1eefcf817651bb73dcbf667ba2f",
+  "sha256": "13h9kmcgnfp8wh1yw9ndkjm2hs0g1bw4gd0r624bsnfnbbl74xvg"
 }
diff --git a/release.nix b/release.nix
index d7bf10b9..7d048e28 100644
--- a/release.nix
+++ b/release.nix
@@ -6,25 +6,20 @@
 , supportedSystems ? [ "x86_64-linux" "x86_64-darwin" ]
 }:
 let
-  inherit (local-self) reflex-platform;
   inherit (local-self.nixpkgs) lib;
 
   perPlatform = lib.genAttrs supportedSystems (system: let
     self = import ./. (self-args // { inherit system; });
-    reflex-platform = self.reflex-platform;
     cachePackages =
-      (builtins.attrValues (self.rhyolitePackages self.obelisk))
+      (builtins.attrValues self.rhyolitePackages)
       ++ [
         self.proj.ghcjs.rhyolite-frontend
-        (import ./. {}).proj.ghc.rhyolite-test-suite
+        self.proj.ghc.rhyolite-test-suite
       ];
-  in self.rhyolitePackages self.obelisk // {
-    cache = reflex-platform.pinBuildInputs "rhyolite-${system}" cachePackages;
+  in self.proj // {
+    recurseForDerivations = true;
   });
 
-  metaCache = reflex-platform.pinBuildInputs "rhyolite-everywhere"
-    (map (a: a.cache) (builtins.attrValues perPlatform));
-
 in perPlatform // {
-  inherit metaCache;
+  recurseForDerivations = true;
 }