diff --git a/build.sbt b/build.sbt
index c5d74fe7..f126dbf5 100644
--- a/build.sbt
+++ b/build.sbt
@@ -556,7 +556,14 @@ val restserver = project
       "-Xmx150M",
       "-XX:+UseG1GC"
     ),
-    Revolver.enableDebugging(port = 5050, suspend = false)
+    Revolver.enableDebugging(port = 5050, suspend = false),
+    Universal / mappings := {
+      val allMappings = (Universal / mappings).value
+      allMappings.filter {
+        //scalajs artifacts are not needed at runtime
+        case (file, name) => !name.contains("_sjs1_")
+      }
+    }
   )
   .dependsOn(restapi, joexapi, backend, webapp, ftssolr)
 
@@ -771,7 +778,7 @@ def packageTools(logger: Logger, dir: File, version: String): Seq[File] = {
 
 addCommandAlias(
   "make",
-  ";set webapp/elmCompileMode := ElmCompileMode.Production; set webapp/stylesMode := StylesMode.Prod ;root/openapiCodegen ;root/test:compile"
+  ";set webapp/elmCompileMode := ElmCompileMode.Production; set webapp/stylesMode := StylesMode.Prod ;root/openapiCodegen ;root/Test/compile"
 )
 addCommandAlias("make-zip", ";restserver/universal:packageBin ;joex/universal:packageBin")
 addCommandAlias("make-deb", ";restserver/debian:packageBin ;joex/debian:packageBin")
diff --git a/project/build.nix b/project/build.nix
index 21eba62c..410459e1 100644
--- a/project/build.nix
+++ b/project/build.nix
@@ -1,13 +1,13 @@
 let
-    nixpkgsUnstable = builtins.fetchTarball {
-    url = "https://github.com/NixOS/nixpkgs-channels/archive/nixos-unstable.tar.gz";
+  nixpkgs = builtins.fetchTarball {
+    url = "https://github.com/NixOS/nixpkgs/archive/nixos-20.09.tar.gz";
   };
-  pkgsUnstable = import nixpkgsUnstable { };
-  initScript = pkgsUnstable.writeScript "docspell-build-init" ''
+  pkgs = import nixpkgs { };
+  initScript = pkgs.writeScript "docspell-build-init" ''
      export LD_LIBRARY_PATH=
-     ${pkgsUnstable.bash}/bin/bash -c sbt
+     ${pkgs.bash}/bin/bash -c "sbt -mem 2048 -java-home ${pkgs.openjdk11}/lib/openjdk"
   '';
-in with pkgsUnstable;
+in with pkgs;
 
 buildFHSUserEnv {
   name = "docspell-sbt";