diff --git a/flake.nix b/flake.nix
index 2a70ad98b..b5929a5ee 100644
--- a/flake.nix
+++ b/flake.nix
@@ -24,17 +24,31 @@
       packages = forAllSystems (system:
         let
           pkgs = nixpkgsFor.${system};
+          # Directories that are neither needed for building the frontend nor the backend.
+          # For better build caching.
+          unrelatedDirs = [
+                "flake.lock"
+                (filter.matchExt "nix")
+            "docs"
+            "docker"
+            "docker-compose.test.yml"
+            "docker-compose.yml"
+            "generate-test-data"
+          ];
         in
         {
           mobilizon = pkgs.callPackage ./. {
             src = filter {
               root = ./.;
               exclude = [
-                "flake.lock"
-                (filter.matchExt "nix")
                 "src"
                 (filter.matchExt "js")
-              ];
+                (filter.matchExt "ts")
+                (filter.matchExt "json")
+                "tests"
+                "scripts"
+                "public"
+              ] ++ unrelatedDirs;
             };
             src-config = ./config;
             mobilizon-js = self.packages."${system}".mobilizon-frontend;
@@ -50,11 +64,12 @@
               (filter {
                 root = ./.;
                 exclude = [
-                  "flake.lock"
-                  (filter.matchExt "nix")
                   "lib"
                   "config"
-                ];
+                  "test"
+                  "rel"
+                  "support"
+                ] ++ unrelatedDirs;
               })
               {
                 inherit nodejs;