Track what happened to each text

How to do it

Pass a status callback address with each send and verify its signature, as in verify webhook signatures. Store the provider's message ID, status, error code and cost against the send. Do not retry a text marked undelivered for an invalid or unreachable number. Suppress a number after 3 such failures in a row. Watch daily cost per country next to the pumping alerts.

Example

app.post('/sms/status', verifyProviderSignature, async (req, res) => {
  const { MessageSid, MessageStatus, ErrorCode, To } = req.body;
  await db.sends.updateStatus(MessageSid, MessageStatus, ErrorCode);
  if (MessageStatus === 'undelivered' && (await db.sends.recentFailures(To)) >= 3) await db.smsSuppressions.add(To);
  res.sendStatus(204);
});

@app.post("/sms/status")
def sms_status():
    verify_provider_signature(request)
    form = request.form
    db.sends.update_status(form["MessageSid"], form["MessageStatus"], form.get("ErrorCode"))
    if form["MessageStatus"] == "undelivered" and db.sends.recent_failures(form["To"]) >= 3:
        db.sms_suppressions.add(form["To"])
    return "", 204

How to check

Send to a provider test number that always fails. The send row shows the failure code, and after the third failure the number is suppressed.