How to Monitor Your Deno Application with Vigilmon

Deno is a secure TypeScript runtime gaining fast adoption. This guide shows you how to add uptime monitoring to your Deno app with Vigilmon.

Health Endpoint with Oak Framework

import { Application, Router } from 'https://deno.land/x/oak@v12.6.1/mod.ts';

const router = new Router();

router.get('/health', (ctx) => {
  ctx.response.body = {
    status: 'ok',
    runtime: 'deno',
    version: Deno.version.deno,
    timestamp: new Date().toISOString(),
  };
});

const app = new Application();
app.use(router.routes());
app.use(router.allowedMethods());
await app.listen({ port: 8000 });

Health Endpoint with Hono

import { Hono } from 'npm:hono';

const app = new Hono();

app.get('/health', (c) => c.json({ status: 'ok', ts: new Date().toISOString() }));

Deno.serve(app.fetch);

Health Endpoint with Fresh Framework

// routes/health.ts
import { Handlers } from '$fresh/server.ts';

export const handler: Handlers = {
  GET(_req) {
    return new Response(
      JSON.stringify({ status: 'ok' }),
      { headers: { 'Content-Type': 'application/json' } }
    );
  },
};

Deno KV Health Check

If you use Deno KV, include it in your health check:

router.get('/health', async (ctx) => {
  const checks: Record<string, string> = {};

  try {
    const kv = await Deno.openKv();
    await kv.set(['health_probe'], 'ok');
    const entry = await kv.get(['health_probe']);
    checks.kv = entry.value === 'ok' ? 'ok' : 'miss';
  } catch {
    checks.kv = 'error';
  }

  const allOk = Object.values(checks).every(v => v === 'ok');
  ctx.response.status = allOk ? 200 : 503;
  ctx.response.body = { status: allOk ? 'ok' : 'degraded', checks };
});

Add to Vigilmon

1. Deploy your app (Deno Deploy, Fly.io, or VPS)
2. Go to vigilmon.online
3. Click Add Monitor and enter your health URL
4. Set interval: 1 minute
5. Add email or Slack alerts

Deno Deploy Monitoring

If you use Deno Deploy, your app URL is https://your-app.deno.dev. Vigilmon monitors this external endpoint from multiple global locations, catching incidents even when Deno Deploy's own status page is delayed.

Start free at vigilmon.online — no credit card required.