Health Checks

Smart Deploy verifies your app is reachable after deploy and continues probing running deployments for runtime health.

Post-deploy verification

After ECS rollout (or static publish), the deploy pipeline runs verification:

Verification logs include ECS service events and filtered CloudWatch excerpts on failure.

Adding a health endpoint (recommended)

Expose a lightweight route that returns 200 when your app is ready:

// Express example
app.get('/health', (_req, res) => res.status(200).send('ok'));

# FastAPI example
@app.get("/health")
def health():
    return {"status": "ok"}

If your app only serves SPA routes, / may return 200 once the server is up — verification can succeed without a dedicated /health.

Database-dependent health

For production-grade checks, verify critical dependencies:

app.get('/health', async (_req, res) => {
  await db.ping();
  res.status(200).send('ok');
});

Keep checks fast — verification runs repeatedly during the deploy window.

Static sites

Static S3 deploys verify the public URL serves expected content (HTTP success on probed paths). No container process — ensure index.html is at the correct S3 prefix.

Common verification failures

See Startup and Runtime Failures.

Runtime health (ongoing)

Separate from deploy verification, a background reconciler probes running deployments every ~10 minutes.

See Runtime Health.

Related

• Deployment Pipeline
• Debugging Deployments
• Error Catalog — DEPLOYMENT_VERIFICATION_FAILED