diff --git a/Dockerfile b/Dockerfile
index ded6532..e4b39ef 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,10 @@
-# Stage 1: build the React SPA
-FROM node:22-slim AS frontend-build
+# Stage 1: build the React SPA.
+# Pin to the native build host ($BUILDPLATFORM) so the Node/V8 build never runs
+# under QEMU during multi-arch builds — emulated Node crashes V8's baseline JIT
+# (SIGTRAP / exit 133 on `npm ci`). The dist/ output is static JS/CSS, i.e.
+# architecture-independent, so building it once and COPYing it into each
+# target-arch runtime stage is both correct and avoids the emulator entirely.
+FROM --platform=$BUILDPLATFORM node:22-slim AS frontend-build
 
 WORKDIR /frontend