Key Takeaways
- GDPR-minded data handling for open-source / self-built SMS stacks: treat MSISDNs and message bodies as personal data you chose to process.
- The Android handset and your logs often hold more than the API response — document both.
- Priced by devices and SMS send volume. You use your own phone and operator SMS credit. Compliance work does not replace BYO phone and operator credit.
- Free 300 SMS lifetime still creates real message records — purge demos.
- Link privacy policy + retention; do not invent legal advice.
- Isolate OTP content from marketing exports.
GDPR-minded data handling for teams running Android SIM gateways (including open-source experiments on GitHub) starts with one fact: phone numbers and SMS text are personal data when they identify people. Hub: core GDPR how-to. Privacy Policy. GDPR.eu overview.
Priced by devices and SMS send volume. You use your own phone and operator SMS credit.
Shipping an open-source modem stack does not erase Article 5 — your README cannot outrank retention and purpose limitation.
What you process vs what the gateway stores
Your app decides recipients and bodies. The control plane queues jobs and may retain history by plan. The handset SMS app may keep copies on-device. Map all three. Product posture: Security.
Data classes and retention instincts
| Data | Sensitivity | Instinct |
|---|---|---|
| MSISDN | High | Need + retention limit |
| OTP body | High | Short TTL; avoid long log keep |
| Marketing copy | Medium | Consent + STOP linked |
| Device last-seen | Ops | Keep for health, not profiling |
Minimize SMS bodies and logs
Prefer opaque references over full PII in text. Strip secrets from support exports. Related: log retention.
Access, export, deletion
Know how you fulfill access/erasure across API history, warehouse copies, and the physical phone. Document who can open the panel.
Phones are still endpoints
Lost handsets, unlocked screens, and shared SIMs are data incidents waiting to happen. Pair with charged, locked devices — multi-device ops.
Related reading
Secure API keys in env. Document runbooks.
Checklist
- Purpose recorded for each SMS lane.
- Retention written (API + device + logs).
- OTP not in long-lived storage.
- Access limited to need-to-know.
- STOP / consent for marketing.
- Counsel reviewed for your jurisdiction.
Next steps
Align runbooks with counsel, then operate on devices + volume with BYO Android and carrier credit.
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




