Does back-in-stock SMS include carrier credit?

No. Priced by devices and SMS send volume. You use your own phone and operator SMS credit. The waitlist SIM still needs operator balance.

Can inventory.restocked share the checkout OTP phone?

No. Isolate OTP so a restock wave cannot starve login codes.

What must the worker prove before send?

HMAC, sku+waitlist-id idempotency, opted-in waitlist row, no cart topic on this radio.

Android SMS Gateway Scenario 457: Ecommerce webhooks in practice

Key Takeaways

Back-in-stock SMS fires only after HMAC and sku+waitlist-id checks say the restock is new — not on cart or paid webhooks.
A retried inventory.restocked without idempotency burns airtime and looks like two restocks.
Priced by devices and SMS send volume. You use your own phone and operator SMS credit. Free is 300 SMS lifetime; Developer is 25,000 SMS per year.
This is our Android SIM gateway, not a CodeCanyon shop plugin. MCP only wraps REST if you add it.
Checkout OTP never shares the waitlist radio.
Developer Center owns live webhook fields.

Summary

A restock ping is not a cart ping. Fire back-in-stock SMS only after HMAC and sku+waitlist-id checks say the restock is new, and keep checkout OTP off the waitlist radio. Priced by devices and SMS send volume. You use your own phone and operator SMS credit.

If inventory.restocked retries without a waitlist lock, the shopper gets two pings and you pay twice.

Back-in-stock vs cart

Topic	SMS?	Guard
inventory.restocked	Yes, after HMAC + waitlist-id	Idempotency lock
cart / paid	Never on this radio	Wrong topic
Checkout OTP	Never	Isolate

Key takeaways

HMAC and waitlist-id before any restock SMS.
Cart and paid topics stay off the waitlist radio.
Checkout OTP never shares this SIM.
Priced by devices and SMS send volume. You use your own phone and operator SMS credit.
Not a CodeCanyon shop plugin. MCP wraps REST if you add it.
Canary one staff waitlist before a restock wave.

Context

Store engineers use this ecommerce scenario to fire restock SMS only after HMAC and waitlist-id checks say the SKU is new.

Radio reality still wins: offline phones and OEM killers break scenarios overnight.

Cross-link hub cornerstones instead of rewriting the product overview.

Keep examples conceptual until Developer Center confirms live request shapes.

Budget airtime for retries — failed loops still cost operator credit.

Core scenario guidance

Map inventory.restocked, waitlist-expired, and checkout-OTP to separate templates and radios before you subscribe restock topics.

Separate configuration mistakes from radio failures during incidents.

Write acceptance criteria before seasonal or clinic-hour traffic.

Prefer gradual rollout with feature flags when automation is involved.

Cost and ownership

Model a restock wave as devices plus volume plus airtime on every un-deduped retry. Free is 300 lifetime SMS; Developer is 25,000 SMS per year.

Failed retries still burn credit during scenario experiments.

Assign who owns SIM top-ups and spare handsets.

Keep marketing spend out of OTP device pools.

Operations

Daily checks: pairing health, battery, queue depth, and DLR anomalies.

After OEM updates or SIM swaps, re-test the scenario path end to end.

Keep a spare charged device ready for failover drills.

Name an on-call owner before unattended sends go live.

Security and compliance

Protect API keys per environment; rotate after contractor access ends.

STOP and consent still apply on promotional scenario lanes.

Avoid logging full OTP bodies into shared chat.

Verify webhook signatures and TLS on every callback path.

Decision guide

Ship back-in-stock webhooks only when HMAC, waitlist-id idempotency, and OTP isolation are written.

Delay if you cannot explain offline-phone behavior during peak hours.

If zero phone ops is mandatory, evaluate CPaaS for that lane.

If local SIM economics matter, harden the Android path and monitor airtime.

Checklist

Scenario moments listed with owners.
OTP vs marketing isolation confirmed.
Spare device funded and paired.
Canary on staff numbers passed.
Developer Center checked if API-shaped.
Webhook/DLR monitoring ready.
Airtime budget includes retries.
On-call owner named.
Rollback path documented.
Hub cornerstone reviewed.

Next steps

Return to Phone as SMS gateway guide, compare device and SMS volume pricing, open device setup guide, and confirm APIs in SMS API documentation.

Deep dive: production hardening

Clinic reminders need consent records and STOP handling even when messages feel transactional.

Logistics ETAs should degrade gracefully when devices go offline mid-route.

Edtech OTP spikes at exam windows — capacity plan devices before the semester starts.

Fintech OTP is high-stakes: isolate devices, rotate keys, and avoid logging full codes.

Real-estate nurture is promotional; keep it off OTP SIMs and honor quiet hours.

Restaurant reservation SMS still needs STOP on marketing lanes.

SaaS onboarding OTPs should canary on staff numbers before paid scale.

Field-service dispatch needs two-way inbox ownership so techs are not double-booked.

Marketplace seller alerts need multi-device failover when a single phone is the SPOF.

NGO outreach must separate fundraising blasts from operational alerts.

Appointment businesses live on reminder deliverability the morning of the visit.

Bulk CSV import needs validation before radio send; bad rows burn airtime.

Scheduled SMS must survive device sleep and timezone mistakes.

Auto-reply and STOP protect promotional lanes — never auto-reply into OTP threads.

Dual SIM routing fails when slot maps drift after reboot without re-pair.

Multi-device failover only helps if spare phones stay charged and paired.

MMS attachments inherit carrier size and APN limits.

USSD requests are carrier- and region-sensitive; treat timeouts as expected.

Contact lists need consent metadata stored with the number.

OTP priority queues fail when marketing blasts share the same device pool.

Spare charged devices matter more than brochure SLAs when phones send the SMS.

Airtime surprise bills happen when bulk loops ignore radio pace.

OTP and marketing must stay on separate lanes on every scenario.

Never claim unlimited free cloud SMS credits with no device or volume meter.

Name an on-call owner before unattended schedules go live.

Canary on staff numbers before customer OTP.

Battery exemptions and OEM killers dominate overnight reliability.

Cross-link Setup, Pricing, Downloads, and Developer Center with keyword-rich anchors.

If zero phone ops is mandatory, evaluate CPaaS for that lane instead.

Webhook signature verification is non-negotiable for scenario automation.

Document who owns SIM top-ups for multi-site scenario rollouts.

Prefer honest latency expectations over marketing claims about global SLAs on SIM paths.

Scenario playbooks still bill by devices and SMS send volume. You bring the Android phone and operator SMS credit.

Developer Center owns live API parameters. Scenario blogs teach process and failure modes, not endpoint catalogs.

Ecommerce webhooks must verify signatures before they trigger SMS sends.