diff --git a/platform/api/src/server.js b/platform/api/src/server.js
index 0db3766..4cf1e18 100644
--- a/platform/api/src/server.js
+++ b/platform/api/src/server.js
@@ -76,6 +76,18 @@ function wrap(fn) {
   return (req, res, next) => fn(req, res, next).catch(next);
 }
 
+// GET /healthz — unauthenticated liveness/readiness probe for uptime monitoring and Ansible
+// deploy smoke tests (Phase 4, docs/OBSERVABILITY.md §"uptime checks"). Confirms the process is
+// up AND can reach Postgres — deliberately minimal, no student/instructor data, no auth.
+app.get('/healthz', async (req, res) => {
+  try {
+    await getPool().query('SELECT 1');
+    res.json({ ok: true, db: 'ok' });
+  } catch (e) {
+    res.status(503).json({ ok: false, db: 'unreachable' });
+  }
+});
+
 // ═══════════════════════════════════════════════════════════════════════════════════════
 // STUDENT-FACING: roster / login / session
 // ═══════════════════════════════════════════════════════════════════════════════════════
diff --git a/platform/gateway/src/server.js b/platform/gateway/src/server.js
index 86dc6db..09c230c 100644
--- a/platform/gateway/src/server.js
+++ b/platform/gateway/src/server.js
@@ -49,6 +49,12 @@ proxy.on('error', (err, req, res) => {
   }
 });
 
+// GET /healthz — the Gateway's own liveness check, answered locally without proxying anywhere
+// (Phase 4, docs/OBSERVABILITY.md §"uptime checks"). Deliberately doesn't depend on Platform
+// API/Provisioner being reachable, so it can distinguish "Gateway itself is down" from
+// "something behind it is down" for alerting.
+app.get('/healthz', (req, res) => res.json({ ok: true }));
+
 function parseCookies(req) {
   const header = req.headers.cookie;
   if (!header) return {};