The simplest way to know your student is actually using the app: get a phone notification when they redeem a credit.

Pushover

Pushover takes a one-time $5/platform purchase and offers an HTTP API. The MathNet webhook can’t post directly to Pushover’s /messages.json endpoint because the payload formats differ — but you can use a one-line bridge.

Option 1: Direct (with a tiny relay)

If you run anything that can receive a webhook and forward it — a Cloudflare Worker, a small Lambda, a Pi running webhook, or a Home Assistant rest_command — point MathNet at it and have it call Pushover:

# Cloudflare Worker example
addEventListener('fetch', event => {
  event.respondWith(handle(event.request))
})

async function handle(req) {
  const data = await req.json()
  return fetch('https://api.pushover.net/1/messages.json', {
    method: 'POST',
    headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
    body: new URLSearchParams({
      token: 'YOUR_APP_TOKEN',
      user: 'YOUR_USER_KEY',
      title: 'MathNet credit redeemed',
      message: `${data.device_name} has ${data.balance_after} credits left`
    })
  })
}

ntfy

ntfy.sh is free, self-hostable, and accepts simple HTTP POSTs. You can point MathNet directly at a ntfy topic URL with no relay:

https://ntfy.sh/your-secret-topic-name

ntfy will deliver the JSON body as the notification text. Pick a long, secret topic name — anyone who knows the topic can subscribe.

For a nicer notification, run a one-line relay (Cloudflare Worker, etc.) that reformats the payload into ntfy’s title/message/priority fields:

curl -H "Title: Credit redeemed" \
     -H "Tags: tada" \
     -d "Balance: 4 credits" \
     https://ntfy.sh/your-secret-topic-name

Self-hosting ntfy alongside Home Assistant or on a small VPS gives you the most control. The free hosted ntfy.sh is fine for low-volume family use.

Which to pick?

  • Pushover: more polished, higher reliability, supports priorities/sounds. Pay once per platform.
  • ntfy: free, open source, self-hostable, perfectly fine for “did they practice today?” notifications.

Both are great. Pushover is what most parents end up at after trying both.