diff --git a/apps/api/Dockerfile b/apps/api/Dockerfile
index d55f9d9..18985d9 100644
--- a/apps/api/Dockerfile
+++ b/apps/api/Dockerfile
@@ -28,6 +28,8 @@ ENV NODE_ENV=production
 COPY . .
 WORKDIR /app/apps/api
 EXPOSE 4000
+# Use 127.0.0.1, not localhost: the server binds IPv4 only, and busybox wget
+# resolves localhost to ::1 first — which would refuse and fail the check.
 HEALTHCHECK --interval=20s --timeout=4s --start-period=20s --retries=3 \
-  CMD wget -qO- http://localhost:4000/health || exit 1
+  CMD wget -qO- http://127.0.0.1:4000/health || exit 1
 CMD ["pnpm", "start"]
diff --git a/apps/runner-template/Dockerfile b/apps/runner-template/Dockerfile
index ee9d823..cf40407 100644
--- a/apps/runner-template/Dockerfile
+++ b/apps/runner-template/Dockerfile
@@ -10,6 +10,8 @@ COPY --from=deps /app/node_modules ./node_modules
 COPY package.json tsconfig.json ./
 COPY src ./src
 EXPOSE 3000
+# 127.0.0.1, not localhost: busybox wget resolves localhost to ::1 first and
+# the server binds IPv4 only, so a localhost check would wrongly fail.
 HEALTHCHECK --interval=15s --timeout=3s --start-period=10s --retries=3 \
-  CMD wget -qO- http://localhost:3000/health || exit 1
+  CMD wget -qO- http://127.0.0.1:3000/health || exit 1
 CMD ["npx", "tsx", "src/server.ts"]