diff --git a/nix/default.nix b/nix/default.nix
index 84552c4d52..fe498d5a56 100644
--- a/nix/default.nix
+++ b/nix/default.nix
@@ -21,28 +21,49 @@ let
     in
       if localCommonSrc != ""
       then localCommonSrc
-      else
-        let sources = import ./sources.nix; in sources.common;
+      else sources.common;
+
+  sources = import sourcesnix { sourcesFile = ./sources.json; inherit pkgs; };
+
+  sourcesnix = builtins.fetchurl
+    https://raw.githubusercontent.com/nmattia/niv/506b896788d9705899592a303de95d8819504c55/nix/sources.nix;
+
+  pkgs = import commonSrc {
+    inherit system crossSystem config;
+    overlays = [
+      (
+        self: super:
+          let
+            nixFmt = self.lib.nixFmt { root = ../.; };
+          in
+            {
+              sources = super.sources // sources;
+
+              inherit releaseVersion;
+
+              isMaster = super.isMaster or false;
+
+              # The dfinity-sdk.packages.cargo-security-audit job has this RustSec
+              # advisory-db as a dependency so we add it here to the package set so
+              # that job has access to it.
+              # Hydra injects the latest RustSec-advisory-db, otherwise we piggy
+              # back on the one defined in sources.json.
+              RustSec-advisory-db =
+                if ! isNull RustSec-advisory-db
+                then RustSec-advisory-db
+                else self.sources.advisory-db;
+
+              motoko = import self.sources.motoko { system = self.system; };
+              dfinity = (import self.sources.dfinity { inherit (self) system; }).dfinity.rs;
+              napalm = self.callPackage self.sources.napalm {
+                pkgs = self // { nodejs = self.nodejs-12_x; };
+              };
+
+              inherit (nixFmt) nix-fmt;
+              nix-fmt-check = nixFmt.check;
+            } // import ./overlays/dfinity-sdk.nix self super
+      )
+    ] ++ overlays;
+  };
 in
-import commonSrc {
-  inherit system crossSystem config;
-  overlays = import ./overlays ++ [
-    (
-      _self: super:
-        {
-          inherit
-            releaseVersion
-            ;
-          # The dfinity-sdk.packages.cargo-security-audit job has this RustSec
-          # advisory-db as a dependency so we add it here to the package set so
-          # that job has access to it.
-          # Hydra injects the latest RustSec-advisory-db, otherwise we piggy
-          # back on the one defined in sources.json.
-          RustSec-advisory-db =
-            if ! isNull RustSec-advisory-db
-            then RustSec-advisory-db
-            else super.sources.advisory-db;
-        }
-    )
-  ] ++ overlays;
-}
+pkgs
diff --git a/nix/overlays/default.nix b/nix/overlays/default.nix
deleted file mode 100644
index c5bdbd9573..0000000000
--- a/nix/overlays/default.nix
+++ /dev/null
@@ -1,22 +0,0 @@
-[
-  (_self: super: { isMaster = super.isMaster or false; })
-  (import ./sources.nix)
-  (
-    self: _:
-      let
-        nixFmt = self.lib.nixFmt { root = ../../.; };
-      in
-        # some dependencies
-        {
-          motoko = import self.sources.motoko { system = self.system; };
-          dfinity = (import self.sources.dfinity { inherit (self) system; }).dfinity.rs;
-          napalm = self.callPackage self.sources.napalm {
-            pkgs = self // { nodejs = self.nodejs-12_x; };
-          };
-
-          inherit (nixFmt) nix-fmt;
-          nix-fmt-check = nixFmt.check;
-        }
-  )
-  (import ./dfinity-sdk.nix)
-]
diff --git a/nix/overlays/sources.nix b/nix/overlays/sources.nix
deleted file mode 100644
index a0be4f88cb..0000000000
--- a/nix/overlays/sources.nix
+++ /dev/null
@@ -1,11 +0,0 @@
-# This nixpkgs overlay adds the `sources` attribute to the nixpkgs set which is defined
-# as an attribute set of fetched source code managed by `niv`.
-#
-# Why use an overlay?
-#
-# Without an overlay derivations that need to reference external source code
-# have to use `import ../../../nix/sources.nix` where the path of `../../../`
-# depends on where the derivation is defined relative to `/nix/sources.nix`.
-#
-# With this overlay derivations can just use the `sources` argument from pkgs.
-self: super: { sources = super.sources // import ../sources.nix { pkgs = super; }; }
diff --git a/nix/sources.nix b/nix/sources.nix
deleted file mode 100644
index 6e2bf23180..0000000000
--- a/nix/sources.nix
+++ /dev/null
@@ -1,138 +0,0 @@
-# This file has been generated by Niv.
-
-let
-
-  #
-  # The fetchers. fetch_<type> fetches specs of type <type>.
-  #
-
-  fetch_file = pkgs: spec:
-    if spec.builtin or true then
-      builtins_fetchurl { inherit (spec) url sha256; }
-    else
-      pkgs.fetchurl { inherit (spec) url sha256; };
-
-  fetch_tarball = pkgs: spec:
-    if spec.builtin or true then
-      builtins_fetchTarball { inherit (spec) url sha256; }
-    else
-      pkgs.fetchzip { inherit (spec) url sha256; };
-
-  fetch_git = spec:
-    builtins.fetchGit { url = spec.repo; inherit (spec) rev ref; };
-
-  fetch_builtin-tarball = spec:
-    builtins.trace
-      ''
-        WARNING:
-          The niv type "builtin-tarball" will soon be deprecated. You should
-          instead use `builtin = true`.
-
-          $ niv modify <package> -a type=tarball -a builtin=true
-      ''
-      builtins_fetchTarball { inherit (spec) url sha256; };
-
-  fetch_builtin-url = spec:
-    builtins.trace
-      ''
-        WARNING:
-          The niv type "builtin-url" will soon be deprecated. You should
-          instead use `builtin = true`.
-
-          $ niv modify <package> -a type=file -a builtin=true
-      ''
-      (builtins_fetchurl { inherit (spec) url sha256; });
-
-  #
-  # Various helpers
-  #
-
-  # The set of packages used when specs are fetched using non-builtins.
-  mkPkgs = sources:
-    if hasNixpkgsPath
-    then
-      if hasThisAsNixpkgsPath
-      then import (builtins_fetchTarball { inherit (mkNixpkgs sources) url sha256; }) {}
-      else import <nixpkgs> {}
-    else
-      import (builtins_fetchTarball { inherit (mkNixpkgs sources) url sha256; }) {};
-
-  mkNixpkgs = sources:
-    if builtins.hasAttr "nixpkgs" sources
-    then sources.nixpkgs
-    else abort
-      ''
-        Please specify either <nixpkgs> (through -I or NIX_PATH=nixpkgs=...) or
-        add a package called "nixpkgs" to your sources.json.
-      '';
-
-  hasNixpkgsPath = (builtins.tryEval <nixpkgs>).success;
-  hasThisAsNixpkgsPath =
-    (builtins.tryEval <nixpkgs>).success && <nixpkgs> == ./.;
-
-  # The actual fetching function.
-  fetch = pkgs: name: spec:
-
-    if ! builtins.hasAttr "type" spec then
-      abort "ERROR: niv spec ${name} does not have a 'type' attribute"
-    else if spec.type == "file" then fetch_file pkgs spec
-    else if spec.type == "tarball" then fetch_tarball pkgs spec
-    else if spec.type == "git" then fetch_git spec
-    else if spec.type == "builtin-tarball" then fetch_builtin-tarball spec
-    else if spec.type == "builtin-url" then fetch_builtin-url spec
-    else
-      abort "ERROR: niv spec ${name} has unknown type ${builtins.toJSON spec.type}";
-
-  # Ports of functions for older nix versions
-
-  # a Nix version of mapAttrs if the built-in doesn't exist
-  mapAttrs = builtins.mapAttrs or (
-    f: set: with builtins;
-    listToAttrs (map (attr: { name = attr; value = f attr set.${attr}; }) (attrNames set))
-  );
-
-  # fetchTarball version that is compatible between all the versions of Nix
-  builtins_fetchTarball = { url, sha256 }@attrs:
-    let
-      inherit (builtins) lessThan nixVersion fetchTarball;
-    in
-      if lessThan nixVersion "1.12" then
-        fetchTarball { inherit url; }
-      else
-        fetchTarball attrs;
-
-  # fetchurl version that is compatible between all the versions of Nix
-  builtins_fetchurl = { url, sha256 }@attrs:
-    let
-      inherit (builtins) lessThan nixVersion fetchurl;
-    in
-      if lessThan nixVersion "1.12" then
-        fetchurl { inherit url; }
-      else
-        fetchurl attrs;
-
-  # Create the final "sources" from the config
-  mkSources = config:
-    mapAttrs (
-      name: spec:
-        if builtins.hasAttr "outPath" spec
-        then abort
-          "The values in sources.json should not have an 'outPath' attribute"
-        else
-          spec // { outPath = fetch config.pkgs name spec; }
-    ) config.sources;
-
-  # The "config" used by the fetchers
-  mkConfig =
-    { sourcesFile ? ./sources.json
-    , sources ? builtins.fromJSON (builtins.readFile sourcesFile)
-    , pkgs ? mkPkgs sources
-    }: rec {
-      # The sources, i.e. the attribute set of spec name to spec
-      inherit sources;
-
-      # The "pkgs" (evaluated nixpkgs) to use for e.g. non-builtin fetchers
-      inherit pkgs;
-    };
-in
-mkSources (mkConfig {}) // { __functor = _: settings: mkSources (mkConfig settings); }