diff --git a/Dockerfile b/Dockerfile
index 64008a6..744dec4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,7 +5,7 @@ FROM --platform=$BUILDPLATFORM node:22-alpine AS frontend
 ARG REGISTRY_TOKEN
 WORKDIR /ui
 COPY ui/package.json ui/package-lock.json ui/.npmrc ./
-RUN echo "//gitea.siegeln.net/api/packages/cameleer/npm/:_authToken=${REGISTRY_TOKEN}" >> .npmrc && npm ci
+RUN --mount=type=cache,target=/root/.npm echo "//gitea.siegeln.net/api/packages/cameleer/npm/:_authToken=${REGISTRY_TOKEN}" >> .npmrc && npm ci
 COPY ui/ .
 RUN npm run build
 
@@ -14,11 +14,11 @@ FROM --platform=$BUILDPLATFORM eclipse-temurin:21-jdk-alpine AS build
 WORKDIR /build
 COPY .mvn/ .mvn/
 COPY mvnw pom.xml ./
-# Cache deps — only re-downloaded when POM changes
-RUN ./mvnw dependency:go-offline -B || true
+# Cache deps — BuildKit cache mount persists across --no-cache builds
+RUN --mount=type=cache,target=/root/.m2/repository ./mvnw dependency:go-offline -B || true
 COPY src/ src/
 COPY --from=frontend /ui/dist/ src/main/resources/static/
-RUN ./mvnw package -DskipTests -B
+RUN --mount=type=cache,target=/root/.m2/repository ./mvnw package -DskipTests -B
 
 # Runtime: target platform (amd64)
 FROM eclipse-temurin:21-jre-alpine
diff --git a/ui/sign-in/Dockerfile b/ui/sign-in/Dockerfile
index 442616a..60acef8 100644
--- a/ui/sign-in/Dockerfile
+++ b/ui/sign-in/Dockerfile
@@ -1,8 +1,10 @@
+# syntax=docker/dockerfile:1
+
 FROM --platform=$BUILDPLATFORM node:22-alpine AS build
 ARG REGISTRY_TOKEN
 WORKDIR /ui
 COPY package.json package-lock.json .npmrc ./
-RUN echo "//gitea.siegeln.net/api/packages/cameleer/npm/:_authToken=${REGISTRY_TOKEN}" >> .npmrc && npm ci
+RUN --mount=type=cache,target=/root/.npm echo "//gitea.siegeln.net/api/packages/cameleer/npm/:_authToken=${REGISTRY_TOKEN}" >> .npmrc && npm ci
 COPY . .
 RUN npm run build