Key Takeaways
- Free SMS server API production-readiness is a go/no-go for proving the SIM path — not a license to run customer login on 300 lifetime SMS.
- Sends pause when the Free allowance is exhausted. Upgrade or custom — no silent $0.0x overage.
- Hub J cornerstone: free SMS server. Hub C: the API guide.
- Keys in env, webhooks signed, OTP isolated, phone on a charger: still required on Free.
- Priced by devices and SMS send volume. You use your own phone and operator SMS credit.
- Demo footers may apply on demo accounts. Do not treat Free as unmetered carrier SMS.
Hub J checklist: free sms server checklist for API production readiness. Cornerstone: free SMS server. API hub: Android SMS gateway API. This page is the gate, not a rewrite of either overview.
Priced by devices and SMS send volume. You use your own phone and operator SMS credit.
If your launch plan needs more than 300 lifetime messages, you are not “production on Free.” You are negotiating with a pause button.
What “production ready” means on Free
Ready to prove: pairing, one Bearer send, one DLR or inbound webhook, one staff OTP. Ready for strangers logging into your SaaS at Monday peak: almost never. Device cap is one. Volume is lifetime, not monthly.
Allowance pause is a feature
Free and Developer pause at the plan SMS allowance. Starter/Pro/Business uncap platform send volume but still meter devices; operator airtime is never “unlimited.” Do not retitle this page Unlimited SMS.
Go / no-go table
| Gate | Go on Free | No-go |
|---|---|---|
| Staff canary OTP | Yes, counted | Open signup to the world |
| Webhook signature check | Required even on Free | Skipping because “it is just a trial” |
| Keys in env | Required | Key in the SPA |
| Bulk CSV | No | Burning lifetime on a list |
| Spare device | Not on one-device Free | Promising failover |
API gates before customer traffic
- Bearer from env — keys in env.
- Idempotency on send.
- Accept ≠ delivered.
- Live fields from Developer Center.
Radio gates the dashboard cannot fake
Charger, OEM battery exceptions, SIM credit, last-seen. Troubleshooting.
Customer OTP is usually a no
Lifetime 300 plus one radio is a demo. Use OTP verification on a paid device slot when login is revenue.
When to leave Free
Second device, real volume, or pause scares you. Catalog: devices and SMS volume.
Checklist
- Counted remaining Free SMS before any script.
- Official APK paired, not a random zip.
- Key in env.
- Staff canary succeeded with DLR or eyeball.
- Webhook HMAC if you rely on events.
- No CSV on the OTP idea.
- OEM keep-alive done.
- Pause behavior explained to the founder.
- Privacy/retention thought through.
- Upgrade path booked before public launch.
Next steps
Read what Free includes, then the API. Production is a charged phone and a plan that will not pause mid-login.
Related product pages
Jump to the live product docs for this topic—not another long-form article.
- SMS API documentationLive endpoint reference
- device and SMS volume pricingPlans and allowances
- Android SMS gateway product guideDefinition, product, and how to buy
- download the Android gateway appGet the APK
