Key Takeaways
- Scenario 880 is weekend homework LMS OTP, not exam-hall Monday. Failover must work when campus IT is offline.
- Parent Sunday digests cannot share the student-login radio.
- A spare last touched Friday afternoon is the only spare that counts.
- Device caps (2 / 5 / 15) matter more than uncapped platform volume on Sunday nights.
- Priced by devices and SMS send volume. You use your own phone and operator SMS credit. Free: 1 device / 300 SMS lifetime / 300 contacts. Developer: 25,000 SMS per year.
Android SMS gateway scenario 880 is a K–12 or university LMS that sends homework-portal OTP on Sunday evenings. Exam-week failover essays assume staff in the building. This one assumes an empty lab, a Doze event at 18:00, and parents already angry on email.
Priced by devices and SMS send volume. You use your own phone and operator SMS credit. Multi-device · Developer Center. GSMA.
Sunday homework OTP
Count OTP per 15 minutes from last term’s Sundays. Add retries. If one radio cannot drain the burst, run two live plus a spare. Idempotency stays on the login attempt id so a cutover does not double-send the same code.
A spare that is “in the drawer for exams” will not save Sunday homework. Weekend failover is a Friday pair plus a Sunday heartbeat.
LMS login vs parent digest
| Lane | When | Pool | Failover |
|---|---|---|---|
| Student LMS OTP | Sun 17:00–22:00 | Login Androids | Warm spare required |
| Teacher 2FA | Weekday AM | Same login pool OK | Same spare |
| Parent digest | Sunday PM | Promo / ops SIM | Can delay |
Caps: 2 / 5 / 15 devices.
Nobody in the lab
On-call is remote. Cutover cannot require a badge-in. Worker watches pairing heartbeat, last DLR, battery. Doze.
Spare that survives Saturday OEM
Weekly OEM “optimize” jobs love Saturday. Re-verify exemptions after any update. Dual SIM is not two campuses. Dual SIM.
Auto-cut on heartbeat
Pin new OTP to spare device id. Do not spray both SIMs. REST: PHP, C#. MCP wraps REST.
Devices vs Sunday volume
Priced by devices and SMS send volume. You use your own phone and operator SMS credit. Free: 300 lifetime. Developer: 25,000 SMS per year. Platform unlimited volume on paid tiers is not unlimited carrier SMS. Pricing.
Friday canary
Staff OTP Friday 16:00 and Sunday 16:00. Spare charged. Setup.
Minor accounts
Do not log full OTP. Parent STOP is not a student delete. Rotate contractor keys.
Email magic-link only
If you refuse weekend phone ops, do not offer SMS OTP on Sundays. CPaaS for that lane if needed.
Checklist
- Parent digest ≠ login SIM.
- Sunday 16:00 canary + Friday pair.
- Heartbeat cutover documented.
- Airtime on both SIMs.
- Peak OTP/15m from last term.
Next steps
Disable primary pairing on Saturday in staging; prove Sunday canary hits spare. Downloads · Docs.
Related product pages
Jump to the live product docs for this topic—not another long-form article.
- multi-device and dual SIM routingCapacity and failover
- OTP and 2FA SMS on AndroidAuthentication flows
- SMS delivery reports (DLR)Delivery status tracking
- SMS API documentationLive endpoint reference
