مكتبة الشروحات

A health check endpoint lets load balancers, monitoring tools, container orchestrators, and your own scripts quickly verify whether your application is actually working — not just that the process is running.

Why "Process Running" Isn't Enough

A process can be alive but unable to serve requests — a stuck database connection, an exhausted connection pool, or a deadlocked thread all present as "running" to a process manager while being completely non-functional to real users.

What a Good Health Check Verifies

• The application process itself is responsive
• The database connection is alive
• Any critical external dependencies (Redis, external APIs) are reachable, if the app can't function without them

Basic Health Check (Node.js/Express)

app.get('/health', (req, res) => {
  res.status(200).json({ status: 'ok' });
});

Health Check with Database Verification (Node.js)

app.get('/health', async (req, res) => {
  try {
    await db.query('SELECT 1');
    res.status(200).json({ status: 'ok', database: 'connected' });
  } catch (err) {
    res.status(503).json({ status: 'error', database: 'disconnected' });
  }
});

Basic Health Check (PHP/Laravel)

Route::get('/health', function () {
    try {
        DB::connection()->getPdo();
        return response()->json(['status' => 'ok'], 200);
    } catch (\Exception $e) {
        return response()->json(['status' => 'error'], 503);
    }
});

Basic Health Check (Python/Flask)

@app.route('/health')
def health():
    try:
        db.session.execute('SELECT 1')
        return {'status': 'ok'}, 200
    except Exception:
        return {'status': 'error'}, 503

Testing Manually

curl -i http://127.0.0.1:3000/health

Using Health Checks with Docker

healthcheck:
  test: ["CMD", "curl", "-f", "http://localhost:3000/health"]
  interval: 30s
  timeout: 5s
  retries: 3

See Docker Restart Policies and Healthchecks Explained for full detail.

Using Health Checks with a Load Balancer

Configure your load balancer (or Nginx upstream) to periodically hit the health endpoint and automatically remove unhealthy backends from rotation — see How to Set Up Basic Load Balancing with Nginx.

Using Health Checks for Uptime Monitoring

Point an external monitoring service at your /health endpoint rather than just the homepage — it gives a faster, more specific signal than checking whether an entire page renders correctly.

Security Consideration: Don't Leak Sensitive Detail

Keep the health endpoint's response minimal in production — avoid returning internal error messages, stack traces, or infrastructure details that could help an attacker; a simple status code and generic JSON is sufficient.

Common Errors

Health check always returns 200 even when the app is broken — the endpoint isn't actually testing anything meaningful (like a database query); add a real dependency check as shown above.

Best Practices

• Verify actual dependencies (database, critical external services), not just that the process responds
• Keep the endpoint fast — avoid expensive operations that could themselves cause timeouts
• Don't expose sensitive internal details in the response

Related Articles

• Docker Restart Policies and Healthchecks Explained
• How to Set Up Basic Load Balancing with Nginx
• How to Manage Services with systemd and systemctl