Monitor Heroku Scheduler Jobs with Alert24 Heartbeat Checks

Heroku Scheduler is a simple add-on for running one-off tasks on a schedule. Like cron, it fails silently — if a job fails or the add-on has an issue, you won't know without external monitoring. Alert24 heartbeat checks give you a simple dead-man's switch.

Before you start

1. In Alert24, go to Monitoring → Add check → Heartbeat
2. Name it after your Heroku task (e.g., "Daily summary job")
3. Set Expected interval to match your scheduler frequency:
   • Every 10 minutes → 600 seconds
   • Every hour → 3600 seconds
   • Every day → 86400 seconds
4. Set Grace period to 5–10 minutes (Heroku Scheduler has variable timing)
5. Save and copy the heartbeat URL

Add the ping to your job command

Shell command (simplest)

In Heroku Scheduler, update your job's Command field to append the curl ping:

your-existing-command && curl -fsS https://app.alert24.net/api/hb/YOUR_TOKEN

Ruby / Rails

# lib/tasks/daily_summary.rake
task daily_summary: :environment do
  DailySummary.generate
  # Ping Alert24 on success
  require 'net/http'
  Net::HTTP.get(URI("https://app.alert24.net/api/hb/#{ENV['ALERT24_HB_TOKEN']}"))
end

Python

# jobs/daily_summary.py
import urllib.request, os

def run():
    generate_summary()
    send_emails()
    # Ping Alert24 on success
    urllib.request.urlopen(
        f"https://app.alert24.net/api/hb/{os.environ['ALERT24_HB_TOKEN']}",
        timeout=5
    )

if __name__ == '__main__':
    run()

Node.js

// jobs/daily_summary.js
const https = require('https');

async function run() {
  await generateSummary();
  // Ping Alert24 on success
  await new Promise(r => https.get(
    `https://app.alert24.net/api/hb/${process.env.ALERT24_HB_TOKEN}`, r
  ));
}

run().catch(e => { console.error(e); process.exit(1); });

Store the token as a config var

heroku config:set ALERT24_HB_TOKEN=YOUR_TOKEN --app your-heroku-app

Tips

• Heroku Scheduler timing: Heroku Scheduler runs jobs "approximately" at the scheduled time — it can be up to a few minutes off. Set your grace period to at least 10 minutes for hourly jobs and 30 minutes for daily jobs.
• Exit codes: Heroku Scheduler considers a job successful when the process exits 0. Make sure exceptions in your job code cause a non-zero exit (they typically do by default). If the job exits non-zero, the curl ping won't run — Alert24 fires after the grace period.
• Separate jobs: Create one Alert24 heartbeat check per Heroku Scheduler job. Don't combine multiple jobs behind a single heartbeat — you won't know which one stopped.
• Dyno size: Scheduler jobs run on one-off dynos. Ensure your app has available dyno capacity, otherwise Heroku queues the job and it may run late — account for this in your grace period.