diff --git a/.env.example b/.env.example
index 918a359..563c57c 100644
--- a/.env.example
+++ b/.env.example
@@ -86,6 +86,16 @@ GATEWAY_ADMIN_LOCAL_ACCOUNT_ENABLED=true
 GATEWAY_LOCAL_ACCOUNT_GRACE_DAYS=7
 GATEWAY_LEGACY_PASSWORD_GLOBAL_SALT=
 
+# Web Push is intentionally off until a VAPID key pair and contact subject are
+# configured. The private key file is mounted as a Compose secret and must not
+# be committed. The public key is safe to expose to browsers.
+WEB_PUSH_ENABLED=false
+WEB_PUSH_VAPID_SUBJECT=mailto:admin@example.com
+WEB_PUSH_VAPID_PUBLIC_KEY=
+WEB_PUSH_VAPID_PRIVATE_KEY_FILE=./secrets/web_push_vapid_private_key.example
+WEB_PUSH_POLL_INTERVAL_MS=1000
+WEB_PUSH_OUTBOX_POLL_MS=1000
+
 # Shared image service. The two secret files must contain the values configured
 # for the core2026 caller on the image server and must not be committed.
 IMAGE_SERVICE_URL=https://sam-image.hided.net
diff --git a/.gitignore b/.gitignore
index 31ec611..9dbcb43 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,5 +4,6 @@
 data/*
 !data/image/
 !data/image/.gitkeep
-secrets/
+secrets/*
+!secrets/*.example
 *.log
diff --git a/README.md b/README.md
index f1162bd..cf3c961 100644
--- a/README.md
+++ b/README.md
@@ -110,6 +110,20 @@ mount되며 원문은 환경 변수나 브라우저 bundle에 들어가지 않
 URL query나 `VITE_*`가 아니라 `IMAGE_UPLOAD_CORE2026_SECRET_FILE`이 가리키는
 mode 0600 secret 파일에만 둡니다.
 
+## Web Push 활성화 경계
+
+Gateway의 Android, iPhone과 Windows 브라우저 알림 기반은 포함하지만 기본값은
+`WEB_PUSH_ENABLED=false`입니다. 이 상태에서는 구독 버튼과 전송 worker가
+비활성이고, 알림 이벤트를 나중에 소급 전송할 backlog도 만들지 않습니다.
+
+활성화할 때만 VAPID key pair를 생성하여 공개키는
+`WEB_PUSH_VAPID_PUBLIC_KEY`, private key는 Git에서 제외한
+`WEB_PUSH_VAPID_PRIVATE_KEY_FILE`에 각각 넣고, 운영 연락처를
+`WEB_PUSH_VAPID_SUBJECT`의 `mailto:` 또는 HTTPS URL로 설정합니다. private key는
+runtime의 `/run/secrets/web_push_vapid_private_key`에 Compose secret으로만
+mount됩니다. 설정 후 `./scripts/check.sh`가 키 파일의 존재와 activation 필드를
+검증한 다음 runtime을 재생성해야 하며, 실제 활성화와 배포는 별도 운영 작업입니다.
+
 ## 데이터와 복구 경계
 
 - PostgreSQL, Redis, Core clone/worktree, PM2 상태와 Caddy 인증서는 named
diff --git a/compose.yaml b/compose.yaml
index a726ee0..1b64faa 100644
--- a/compose.yaml
+++ b/compose.yaml
@@ -117,6 +117,12 @@ services:
       GATEWAY_ADMIN_LOCAL_ACCOUNT_ENABLED: ${GATEWAY_ADMIN_LOCAL_ACCOUNT_ENABLED:-true}
       GATEWAY_LOCAL_ACCOUNT_GRACE_DAYS: ${GATEWAY_LOCAL_ACCOUNT_GRACE_DAYS:-7}
       GATEWAY_LEGACY_PASSWORD_GLOBAL_SALT: ${GATEWAY_LEGACY_PASSWORD_GLOBAL_SALT:-}
+      WEB_PUSH_ENABLED: ${WEB_PUSH_ENABLED:-false}
+      WEB_PUSH_VAPID_SUBJECT: ${WEB_PUSH_VAPID_SUBJECT:-}
+      WEB_PUSH_VAPID_PUBLIC_KEY: ${WEB_PUSH_VAPID_PUBLIC_KEY:-}
+      WEB_PUSH_VAPID_PRIVATE_KEY_FILE: /run/secrets/web_push_vapid_private_key
+      WEB_PUSH_POLL_INTERVAL_MS: ${WEB_PUSH_POLL_INTERVAL_MS:-1000}
+      WEB_PUSH_OUTBOX_POLL_MS: ${WEB_PUSH_OUTBOX_POLL_MS:-1000}
       GATEWAY_API_HOST: 0.0.0.0
       GATEWAY_API_PORT: '15001'
       GATEWAY_FRONTEND_PORT: '15000'
@@ -151,6 +157,8 @@ services:
       - frontend-artifacts:/srv/frontend-artifacts
       - ${IMAGE_UPLOAD_CORE2026_SECRET_FILE:?set IMAGE_UPLOAD_CORE2026_SECRET_FILE in .env}:/run/secrets/image_upload_core2026_secret:ro
       - ${IMAGE_SYNC_CORE2026_SECRET_FILE:?set IMAGE_SYNC_CORE2026_SECRET_FILE in .env}:/run/secrets/image_sync_core2026_secret:ro
+    secrets:
+      - web_push_vapid_private_key
     depends_on:
       postgres:
         condition: service_healthy
@@ -192,6 +200,10 @@ services:
         condition: service_healthy
     restart: unless-stopped
 
+secrets:
+  web_push_vapid_private_key:
+    file: ${WEB_PUSH_VAPID_PRIVATE_KEY_FILE:-./secrets/web_push_vapid_private_key.example}
+
 volumes:
   postgres-data:
   redis-data:
diff --git a/runtime/validate-compose-model.mjs b/runtime/validate-compose-model.mjs
index a78d4e9..16e78a9 100644
--- a/runtime/validate-compose-model.mjs
+++ b/runtime/validate-compose-model.mjs
@@ -49,6 +49,20 @@ export const validateComposeModel = (model, mode) => {
   if (!artifactMount || artifactMount.read_only === true) {
     errors.push('/srv/frontend-artifacts must be a writable runtime volume');
   }
+  if (!['true', 'false'].includes(runtime.environment?.WEB_PUSH_ENABLED)) {
+    errors.push('WEB_PUSH_ENABLED must be literal true or false');
+  }
+  if (runtime.environment?.WEB_PUSH_VAPID_PRIVATE_KEY_FILE !== '/run/secrets/web_push_vapid_private_key') {
+    errors.push('WEB_PUSH_VAPID_PRIVATE_KEY_FILE must use the mounted Compose secret');
+  }
+  const webPushSecret = (Array.isArray(runtime.secrets) ? runtime.secrets : []).find(
+    (candidate) => candidate?.target === '/run/secrets/web_push_vapid_private_key',
+  );
+  if (!webPushSecret) errors.push('the VAPID private key must be mounted as a runtime secret');
+  if (runtime.environment?.WEB_PUSH_ENABLED === 'true') {
+    if (!runtime.environment?.WEB_PUSH_VAPID_SUBJECT) errors.push('WEB_PUSH_VAPID_SUBJECT must be configured');
+    if (!runtime.environment?.WEB_PUSH_VAPID_PUBLIC_KEY) errors.push('WEB_PUSH_VAPID_PUBLIC_KEY must be configured');
+  }
   const caddyArtifactMount = (Array.isArray(caddy?.volumes) ? caddy.volumes : []).find(
     (candidate) => candidate?.target === '/srv/frontend-artifacts',
   );
diff --git a/runtime/validate-env.mjs b/runtime/validate-env.mjs
index 0d3482f..3916b9f 100644
--- a/runtime/validate-env.mjs
+++ b/runtime/validate-env.mjs
@@ -108,6 +108,25 @@ export const validateEnvironment = (env) => {
     errors.push('CORE_SSH_KNOWN_HOSTS_BASE64 must contain valid base64-encoded known_hosts data');
   }
 
+  const webPushEnabled = env.WEB_PUSH_ENABLED?.trim() === 'true';
+  if (env.WEB_PUSH_ENABLED && !['true', 'false'].includes(env.WEB_PUSH_ENABLED.trim())) {
+    errors.push('WEB_PUSH_ENABLED must be true or false');
+  }
+  if (webPushEnabled) {
+    const subject = env.WEB_PUSH_VAPID_SUBJECT?.trim() ?? '';
+    const publicKey = env.WEB_PUSH_VAPID_PUBLIC_KEY?.trim() ?? '';
+    const privateKeyFile = env.WEB_PUSH_VAPID_PRIVATE_KEY_FILE?.trim() ?? '';
+    if (!/^(?:mailto:|https:\/\/)/i.test(subject) || isPlaceholder(subject)) {
+      errors.push('WEB_PUSH_VAPID_SUBJECT must be a non-placeholder mailto: or HTTPS contact');
+    }
+    if (!publicKey || isPlaceholder(publicKey)) {
+      errors.push('WEB_PUSH_VAPID_PUBLIC_KEY is required when Web Push is enabled');
+    }
+    if (!privateKeyFile || isPlaceholder(privateKeyFile) || privateKeyFile.endsWith('.example')) {
+      errors.push('WEB_PUSH_VAPID_PRIVATE_KEY_FILE is required when Web Push is enabled');
+    }
+  }
+
   return errors;
 };
 
diff --git a/scripts/check.sh b/scripts/check.sh
index 34e11d0..db2e7e5 100755
--- a/scripts/check.sh
+++ b/scripts/check.sh
@@ -10,7 +10,12 @@ if [ ! -f "$env_file" ]; then
   exit 66
 fi
 
-for key in IMAGE_UPLOAD_CORE2026_SECRET_FILE IMAGE_SYNC_CORE2026_SECRET_FILE; do
+secret_file_keys='IMAGE_UPLOAD_CORE2026_SECRET_FILE IMAGE_SYNC_CORE2026_SECRET_FILE'
+if [ "$(sed -n 's/^WEB_PUSH_ENABLED=//p' "$env_file" | tail -n 1)" = true ]; then
+  secret_file_keys="$secret_file_keys WEB_PUSH_VAPID_PRIVATE_KEY_FILE"
+fi
+
+for key in $secret_file_keys; do
   value=$(sed -n "s/^${key}=//p" "$env_file" | tail -n 1)
   if [ -z "$value" ]; then
     echo "$key must name a readable, non-empty secret file." >&2
@@ -24,6 +29,10 @@ for key in IMAGE_UPLOAD_CORE2026_SECRET_FILE IMAGE_SYNC_CORE2026_SECRET_FILE; do
     echo "$key must name a readable, non-empty secret file." >&2
     exit 66
   fi
+  if [ "$key" = WEB_PUSH_VAPID_PRIVATE_KEY_FILE ] && grep -q '^replace-with-' "$secret_path"; then
+    echo "$key must not use the tracked example placeholder." >&2
+    exit 66
+  fi
 done
 
 docker run --rm --network=none --memory=128m --memory-swap=128m --cpus=1 --pids-limit=64 --env-file "$env_file" \
diff --git a/secrets/web_push_vapid_private_key.example b/secrets/web_push_vapid_private_key.example
new file mode 100644
index 0000000..73baa6e
--- /dev/null
+++ b/secrets/web_push_vapid_private_key.example
@@ -0,0 +1 @@
+replace-with-vapid-private-key
diff --git a/test/validate-compose-model.test.mjs b/test/validate-compose-model.test.mjs
index b17b197..926b432 100644
--- a/test/validate-compose-model.test.mjs
+++ b/test/validate-compose-model.test.mjs
@@ -20,6 +20,8 @@ const safeRuntime = {
     IMAGE_SYNC_SECRET_FILE: '/run/secrets/image_sync_core2026_secret',
     VITE_IMAGE_PUBLIC_URL: 'https://sam-image.hided.net',
     VITE_GATEWAY_USER_ICON_BASE_URL: 'https://sam-image.hided.net/icons',
+    WEB_PUSH_ENABLED: 'false',
+    WEB_PUSH_VAPID_PRIVATE_KEY_FILE: '/run/secrets/web_push_vapid_private_key',
     FRONTEND_SERVE_MODE: 'static',
     FRONTEND_SHARED_ASSET_PUBLIC_PATH: '/gateway/profile-assets',
     RELEASE_BUILDER_URL: 'http://builder:15100',
@@ -45,6 +47,12 @@ const safeRuntime = {
       read_only: true,
     },
   ],
+  secrets: [
+    {
+      source: 'web_push_vapid_private_key',
+      target: '/run/secrets/web_push_vapid_private_key',
+    },
+  ],
   restart: 'unless-stopped',
   mem_limit: String(4 * 1024 * 1024 * 1024),
   memswap_limit: String(4 * 1024 * 1024 * 1024),
@@ -149,3 +157,13 @@ test('rejects missing or excessive build memory and parallelism limits', () => {
   assert.ok(errors.some((error) => error.includes('turn daemon Node heap limit')));
   assert.ok(errors.some((error) => error.includes('Rayon thread count')));
 });
+
+test('requires Web Push activation to keep the private key in a mounted secret', () => {
+  const services = safeServices();
+  services.runtime.environment.WEB_PUSH_ENABLED = 'true';
+  services.runtime.secrets = [];
+  const errors = validateComposeModel({ services }, 'production');
+  assert.ok(errors.some((error) => error.includes('VAPID private key')));
+  assert.ok(errors.some((error) => error.includes('WEB_PUSH_VAPID_SUBJECT')));
+  assert.ok(errors.some((error) => error.includes('WEB_PUSH_VAPID_PUBLIC_KEY')));
+});
diff --git a/test/validate-env.test.mjs b/test/validate-env.test.mjs
index 614b913..305204e 100644
--- a/test/validate-env.test.mjs
+++ b/test/validate-env.test.mjs
@@ -75,3 +75,32 @@ test('rejects credentials embedded in repository URLs and mixed auth modes', ()
   assert.ok(errors.some((error) => error.includes('must not embed credentials')));
   assert.ok(errors.some((error) => error.includes('only one Core repository authentication mode')));
 });
+
+test('keeps Web Push disabled by default and validates activation inputs', () => {
+  assert.deepEqual(validateEnvironment({ ...validEnv, WEB_PUSH_ENABLED: 'false' }), []);
+
+  const errors = validateEnvironment({ ...validEnv, WEB_PUSH_ENABLED: 'true' });
+  assert.ok(errors.some((error) => error.includes('WEB_PUSH_VAPID_SUBJECT')));
+  assert.ok(errors.some((error) => error.includes('WEB_PUSH_VAPID_PUBLIC_KEY')));
+  assert.ok(errors.some((error) => error.includes('WEB_PUSH_VAPID_PRIVATE_KEY_FILE')));
+  assert.ok(
+    validateEnvironment({
+      ...validEnv,
+      WEB_PUSH_ENABLED: 'true',
+      WEB_PUSH_VAPID_SUBJECT: 'mailto:admin@test.invalid',
+      WEB_PUSH_VAPID_PUBLIC_KEY: 'test-public-key',
+      WEB_PUSH_VAPID_PRIVATE_KEY_FILE: './secrets/web_push_vapid_private_key.example',
+    }).some((error) => error.includes('WEB_PUSH_VAPID_PRIVATE_KEY_FILE')),
+  );
+
+  assert.deepEqual(
+    validateEnvironment({
+      ...validEnv,
+      WEB_PUSH_ENABLED: 'true',
+      WEB_PUSH_VAPID_SUBJECT: 'mailto:admin@test.invalid',
+      WEB_PUSH_VAPID_PUBLIC_KEY: 'test-public-key',
+      WEB_PUSH_VAPID_PRIVATE_KEY_FILE: './secrets/web-push-private-key',
+    }),
+    [],
+  );
+});