diff --git a/infra/docker/Dockerfile.backend b/infra/docker/Dockerfile.backend
index 79ca8f8..e832c08 100644
--- a/infra/docker/Dockerfile.backend
+++ b/infra/docker/Dockerfile.backend
@@ -1,4 +1,4 @@
-FROM node:22-alpine
+FROM node:22-slim
 
 WORKDIR /app
 
@@ -6,11 +6,10 @@ WORKDIR /app
 RUN npm install -g pnpm
 
 # Install build tools for native dependencies (node-crc, @discordjs/opus)
-# @discordjs/voice is a shared workspace dependency needed even by backend
-RUN apk add --no-cache python3 make g++
+RUN apt-get update -qq && apt-get install -y -qq --no-install-recommends python3 make g++ wget && rm -rf /var/lib/apt/lists/*
 
 # Create non-root user
-RUN addgroup -S app && adduser -S -G app app
+RUN groupadd --system app && useradd --system -g app app
 
 # Copy dependency definition files first for better caching
 COPY pnpm-workspace.yaml .
diff --git a/infra/docker/Dockerfile.discord-gateway b/infra/docker/Dockerfile.discord-gateway
index 8167c41..e89ef9f 100644
--- a/infra/docker/Dockerfile.discord-gateway
+++ b/infra/docker/Dockerfile.discord-gateway
@@ -11,7 +11,10 @@ RUN addgroup -S app && adduser -S -G app app
 # Install build tools for native dependencies (node-crc, @discordjs/opus)
 # and ffmpeg for voice transmit (PCM to OggOpus encoding)
 # This is done early to cache this expensive layer
-RUN apk add --no-cache python3 make g++ rust cargo ffmpeg
+RUN apk add --no-cache python3 make g++ rust cargo ffmpeg linux-headers
+
+# Use bundled node headers for native addon compilation
+ENV npm_config_nodedir=/usr/local
 
 # Copy dependency definition files first for better caching
 COPY pnpm-workspace.yaml .