diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 15d782b..f01dbf3 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -35,6 +35,7 @@ jobs:
             ${{ runner.os }}-flatpak-builder-
 
       - run: just ci
+      - run: rm -rf .flatpak-builder/build
 
       # Save caches
       - name: Save Flatpak dependencies
diff --git a/build-aux/Makefile b/build-aux/Makefile
index c0a20a3..c07af24 100644
--- a/build-aux/Makefile
+++ b/build-aux/Makefile
@@ -2,7 +2,8 @@
 .PHONY: all
 all:
 	cat po/LINGUAS | while read lang; do mkdir -p assets/locale/$$lang/LC_MESSAGES; msgfmt -o assets/locale/$$lang/LC_MESSAGES/de.leopoldluley.Clapgrep.mo po/$$lang.po; done
-	cargo build --package clapgrep-gnome --release
+	cargo --offline fetch --manifest-path Cargo.toml --verbose
+	cargo --offline build --package clapgrep-gnome --release
 	mkdir -p /app/share/locale
 	install -Dm0755 target/release/clapgrep-gnome /app/bin/clapgrep
 	install -Dm0755 assets/de.leopoldluley.Clapgrep.desktop /app/share/applications/de.leopoldluley.Clapgrep.desktop
diff --git a/build-aux/fun.sh b/build-aux/fun.sh
index 513c7d3..b215a7b 100755
--- a/build-aux/fun.sh
+++ b/build-aux/fun.sh
@@ -1,3 +1,4 @@
 #!/usr/bin/env sh
 
+export CARGO_HOME=/run/build/clapgrep/cargo
 flatpak-builder --run $(dirname $0)/../flatpak $(dirname $0)/de.leopoldluley.Clapgrep.json "$@"
diff --git a/justfile b/justfile
index d3e2fa8..5bb006f 100644
--- a/justfile
+++ b/justfile
@@ -33,6 +33,10 @@ clean:
 build *args: build-translations
   cargo build --package {{frontend}} {{args}}
 
+build-offline *args: build-translations
+  cargo --offline fetch --manifest-path Cargo.toml --verbose
+  cargo --offline build --package {{frontend}} {{args}}
+
 check *args:
   cargo clippy --all-features {{args}}
 
@@ -40,13 +44,13 @@ run *args: build-translations
   env RUST_BACKTRACE=full cargo run --package {{frontend}} {{args}}
 
 ci: setup-flatpak-repos
-  flatpak-builder --delete-build-dirs --disable-updates --build-only --ccache --force-clean flatpak build-aux/{{appid}}.json
+  flatpak-builder --keep-build-dirs --disable-updates --build-only --ccache --force-clean flatpak build-aux/{{appid}}.json
   echo Check formatting:
-  ./build-aux/fun.sh cargo fmt --all -- --check --verbose
+  ./build-aux/fun.sh env CARGO_HOME=/run/build/clapgrep/cargo cargo --offline fmt --all -- --check --verbose
   echo Check code:
-  ./build-aux/fun.sh cargo check
+  ./build-aux/fun.sh env CARGO_HOME=/run/build/clapgrep/cargo cargo --offline check
   echo Check code with Clippy:
-  ./build-aux/fun.sh cargo clippy --workspace --all-targets --all-features -- -D warnings
+  ./build-aux/fun.sh env CARGO_HOME=/run/build/clapgrep/cargo cargo --offline clippy --workspace --all-targets --all-features -- -D warnings
 
 install:
   mkdir -p {{po-dst}}
@@ -60,7 +64,7 @@ make-makefile:
   echo "# This file was generated by 'just make-makefile'" > build-aux/Makefile
   echo ".PHONY: all" >> build-aux/Makefile
   echo "all:" >> build-aux/Makefile
-  just -n build --release 2>&1 | sed 's/^/\t/' | sed 's/\$/$$/g' >> build-aux/Makefile
+  just -n build-offline --release 2>&1 | sed 's/^/\t/' | sed 's/\$/$$/g' >> build-aux/Makefile
   just -n --set prefix /app install 2>&1 | sed 's/^/\t/' >> build-aux/Makefile
 
 prepare-flatpak: make-makefile