diff --git a/.circleci/config.yml b/.circleci/config.yml
index b24b72a..a11b18c 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -23,6 +23,12 @@ jobs:
             echo "keep-outputs = true" | sudo tee -a /etc/nix/nix.conf
             echo "keep-derivations = true" | sudo tee -a /etc/nix/nix.conf
 
+            # Set a new TMP because /run/user is (1) pretty small and (2)
+            # mounted with noexec
+            new_tmp=$HOME/tmp
+            mkdir -p $new_tmp
+            echo "export TMPDIR=$new_tmp" >> $BASH_ENV
+
         # Builds everything from scratch on master. On a branch the branch's
         # cache is used if it exists, otherwise the latest cache generated from
         # master is used.
diff --git a/README.md b/README.md
index 3fd581a..f090ce3 100644
--- a/README.md
+++ b/README.md
@@ -16,10 +16,7 @@ $ nix-env -iA niv -f https://github.com/nmattia/niv/tarball/master
 Inside the provided nix shell:
 
 ``` bash
-$ # GHCi:
-$ snack ghci
-$ # run:
-$ snack run -- <args>
+$ repl
 ```
 
 Run the test suite with this command:
diff --git a/README.tpl.md b/README.tpl.md
index de1d7e4..25d64d9 100644
--- a/README.tpl.md
+++ b/README.tpl.md
@@ -16,10 +16,7 @@ $ nix-env -iA niv -f https://github.com/nmattia/niv/tarball/master
 Inside the provided nix shell:
 
 ``` bash
-$ # GHCi:
-$ snack ghci
-$ # run:
-$ snack run -- <args>
+$ repl
 ```
 
 Run the test suite with this command:
diff --git a/Main.hs b/app/Niv.hs
similarity index 99%
rename from Main.hs
rename to app/Niv.hs
index e0b37a9..ac90698 100644
--- a/Main.hs
+++ b/app/Niv.hs
@@ -6,8 +6,6 @@
 {-# LANGUAGE TupleSections #-}
 {-# LANGUAGE ViewPatterns #-}
 
-module Main (main) where
-
 import Control.Applicative
 import Control.Monad
 import Control.Monad.State
diff --git a/default.nix b/default.nix
index bda28df..9d27d31 100644
--- a/default.nix
+++ b/default.nix
@@ -1,6 +1,31 @@
 { pkgs ? import ./nix {} }:
+with rec
+{ niv-source = pkgs.lib.sourceByRegex ./.
+    [ "^package.yaml$"
+      "^app.*$"
+      "^README.md$"
+    ];
+  haskellPackages = pkgs.haskellPackages.override
+    { overrides = _: haskellPackages:
+        { niv = haskellPackages.callCabal2nix "niv" niv-source {}; };
+    };
+
+  niv-devshell = haskellPackages.shellFor
+    { packages = (ps: [ ps.niv ]);
+      shellHook =
+        ''
+          repl() {
+            ghci Main.hs
+          }
+
+          echo "To start a REPL session, run:"
+          echo "  > repl"
+        '';
+    };
+};
 rec
-{ niv = pkgs.snack-lib.executable ./package.yaml;
+{ inherit niv-source niv-devshell;
+  inherit (haskellPackages) niv;
   readme = pkgs.writeText "README.md"
     (with
       { template = builtins.readFile ./README.tpl.md;
diff --git a/nix/sources.json b/nix/sources.json
index 516998b..e0edb8d 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -1,15 +1,4 @@
 {
-    "snack": {
-        "homepage": "",
-        "url": "https://github.com/nmattia/snack/archive/7b90144a01fff7e5eeb520a6b774377f75e44205.tar.gz",
-        "owner": "nmattia",
-        "branch": "master",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz",
-        "repo": "snack",
-        "sha256": "0p0bldlr83i4bigsv0ygnn7q0lv25hkjd5n4nm1vlvwm9cp8n5dn",
-        "description": "Nix-based incremental build tool for Haskell projects",
-        "rev": "7b90144a01fff7e5eeb520a6b774377f75e44205"
-    },
     "nixpkgs": {
         "url": "https://github.com/NixOS/nixpkgs-channels/archive/8e70d4bd7d5e1c137006fe483d8d116311694bc2.tar.gz",
         "owner": "NixOS",
diff --git a/package.yaml b/package.yaml
index dad8f63..9ec6318 100644
--- a/package.yaml
+++ b/package.yaml
@@ -1,13 +1,19 @@
 name: niv
 
+license: MIT
+
 ghc-options:
     - -Wall
     - -Werror
 
 executable:
-    source-dirs: . # remove when https://github.com/nmattia/snack/pull/96 is merged
-    main: Main.hs
+    main: app/Niv.hs
     dependencies:
+        - base
+        - hashable
+        - process
+        - text
+        - bytestring
         - aeson
         - aeson-pretty
         - directory
diff --git a/shell.nix b/shell.nix
index fa416db..4d49dae 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,4 +1,2 @@
-with { pkgs = import ./nix {}; };
-pkgs.mkShell
-  { buildInputs = [ pkgs.snack-exe ];
-  }
+{ pkgs ? import ./nix {} }:
+(import ./default.nix { inherit pkgs; }).niv-devshell