Key Takeaways
- A log retention policy names what you store (metadata vs body), where it lives (device, panel, your systems), how long, who can export it, and what deletes it.
- OTP codes are credentials. Do not keep full bodies in Slack, tickets, or “debug” buckets that outlive the code.
- DLR status and message ids are usually enough for disputes; full text is a liability after the conversation is over.
- Legal hold is an exception with an owner and an end date — not “keep everything forever in case.”
- Priced by devices and SMS send volume. You use your own phone and operator SMS credit. Retention is a compliance and disk decision, not a billing SKU.
- Align panel exports, device log dumps, and application logs so one layer does not silently keep what another layer deleted.
Teams search android sms gateway app how to log retention policy after a security questionnaire, a GDPR request, or a support thread that pasted an OTP into chat. The Android app will keep working either way. Your lawyers and your on-call will not, if nobody wrote down what a “log” is and when it dies.
This is a Hub D how-to under the app guide. Pair it with delivery reports and GDPR-minded data handling. It is not a product overview and it does not invent a log SKU.
If you cannot say who deletes a message body — and on which calendar day — you do not have a retention policy. You have a pile.
What counts as an SMS log
People mix four things: the control-plane history in the panel, the Android app’s diagnostic dump, your application’s database of sends, and chat screenshots. A policy has to name each store. Deleting one while Slack retains the OTP is not deletion.
- Envelope: message id, device id, timestamps, DLR state, error class.
- Addressing: full MSISDN vs hashed/truncated. Full numbers are personal data in most regimes.
- Body: OTP, appointment text, campaign copy. Highest sensitivity when it is a login code.
- Attachments: MMS URLs the handset fetched. Treat like the body, plus the remote file’s TTL.
- Operator artefacts: raw radio error strings. Useful for a week; noise after that.
Priced by devices and SMS send volume. You use your own phone and operator SMS credit. None of those classes changes how you are billed. They change how long you can be compelled to produce a text, and how badly a laptop theft goes.
Why retention is a policy, not a folder
Support wants history. Security wants less. Finance wants proof a send happened. Product wants to debug a flaky OEM. Those needs conflict. A written policy is how you stop the loudest ticket from setting the default to “keep everything.”
The UK ICO’s storage limitation guidance is a clean reminder: you should not keep personal data longer than you need it. ICO storage limitation is not SMS-specific, but it is the right shape — purpose, period, deletion, exceptions.
Retention classes
Start with four buckets. Change the days for your counsel and your threat model; do not skip the buckets.
| Class | Typical contents | Default keep | Access |
|---|---|---|---|
| OTP operational | id, dest last-4, template id, DLR, latency | 7–30 days | On-call + eng; no Slack paste |
| OTP body | The code itself | Minutes to hours, or never persist | System only; hashed if you must store |
| Transactional / campaign | Envelope + optional body for disputes | 30–180 days | Support with ticket reason |
| Security / audit | Auth failures, key rotations, exports | 1 year or your audit cycle | Security owner |
| Device diagnostics | App log export, OEM crash lines | Until the incident closes + 14 days | Ops; strip numbers before sharing vendors |
If a row has no delete job, it will become “forever” by accident. Put the job name in the runbook next to the number of days.
OTP bodies and PII
A one-time code is a password with a short TTL. Logging it in plaintext next to an email address is a credential dump. Prefer: store a hash if you need replay detection, or store nothing and rely on your app’s own OTP table with its own expiry.
For destinations, last-4 plus a keyed hash beats a spreadsheet of full MSISDNs in a shared drive. When support needs to prove “we texted this person,” a ticket id plus last-4 plus timestamp usually suffices.
Never paste full OTP bodies into shared chat. That sentence belongs in onboarding, not only in this article.
Where the clock actually runs
Retention is not one TTL. The phone, the control plane, and your warehouse each have a clock. If they disagree, the longest clock wins in an investigation — which is usually the one you forgot.
Draw this for your stack: app export TTL, panel history TTL, object-storage lifecycle, warehouse partition, and backup tapes. Backups are where “we deleted it” goes to die. If backups keep message bodies for 35 days, that is your real OTP retention.
Legal hold vs default delete
A hold is a named incident, a ticket, a data range, and a person who lifts it. It is not a global freeze because someone might sue someday. When the hold lifts, the default TTL resumes — including for the copies you made for counsel.
Isolate OTP from marketing in holds too. A campaign dispute should not freeze a year’s worth of login codes.
Exports for support
The app can export diagnostics. Treat that file as customer data: ticket number in the filename, store in a restricted bucket, delete when the incident closes. Redact MSISDNs before you send a dump to an OEM forum.
Panel history exports should match the class table. If support can download bodies for 180 days, say so in the privacy notice. Surprise access is worse than a documented 30-day window.
Phone storage vs control plane vs your backend
The handset is a radio with a chat database. Android SMS apps and OEM tools may keep threads longer than your panel. Physical access to the production phone is therefore a data-access path. Lock the drawer, use a dedicated device, and do not leave a production SIM in a founder’s personal phone that also has family photos backing up to a consumer cloud.
Your backend is usually the system of record for “did we send an OTP.” Design it that way so you are not dependent on a phone’s local thread when a user disputes a login.
Confirm live history APIs in SMS API documentation; this page stays on policy.
Storage limitation without theatre
You do not need a 40-page DPIA to pick 14 days for OTP metadata. You do need: a purpose (“debug failed logins”), a period, a deletion method, and a way to export a person’s data if they ask. If you cannot fulfill an access request because logs are scattered across laptops, fix the store, not the copy.
Consent and STOP still apply on promotional how-tos — retention of opt-out records is often longer than retention of the campaign body, and that is correct. Keep the STOP list.
Checklist
- Four stores named: device, panel, app DB, chat/tickets.
- Class table filled with days and delete jobs.
- OTP bodies not in Slack; hashed or omitted in long stores.
- Backup TTL documented (the real clock).
- Legal hold has an owner and an end.
- Support export path redacts by default.
- Production phones are dedicated and physically controlled.
- Privacy notice matches what you actually keep.
- OTP vs marketing isolation still holds for data, not only radios.
Next steps
Write the class table in the same repo as your send client. Review it after the next Sev-2. Then walk device setup and device and SMS volume pricing so newcomers do not confuse “we keep logs” with “the gateway sells archives.”
A boring default — short OTP metadata, no bodies, longer audit of who exported what — beats a sophisticated policy nobody runs.
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
