In short. An anonymous text leaves almost nothing on the recipient's side — but it leaves a great deal on yours: browser history, gateway cookies, a delivery receipt in your inbox, a notification, your phone's automatic backup, and sometimes a line on a statement. Traces held by the carrier, meanwhile, fall under connection data retained for a year and cannot be deleted on request.
Information verified on 28 October 2026 on the public pages of Légifrance, the CNIL, the Arcep, service-public.fr and cybermalveillance.gouv.fr. This article provides general information and is no substitute for legal advice.
Why are the most revealing traces on your side?
Because the anonymity of a text message consists of withholding an identifier from the display, not of erasing the operation. The recipient sees a short code, an alphanumeric sender, or an unknown number — that's all they have. You, on the other hand, have travelled through an entire chain: a browser, a service, a network, sometimes an email account. Each of those links keeps its own memory.
The consequence is counter-intuitive: in the short term, the person most likely to trace the author of an anonymous text is neither the carrier nor the police, it's someone with access to your phone or your computer. A partner, a colleague, a child, a repair technician. We have already explained why an anonymous text is not truly untraceable; what follows looks at the floor below, far more mundane and far more common.
Three families of traces, to be dealt with in this order:
- Local traces — on the device you used. You control them entirely.
- Traces held by the service — the sending gateway, the inbox, the app. You control part of them, through settings and the right to erasure.
- Network traces — at the carrier. You control none of them, and their retention is a legal obligation.
What traces remain on the device used to send?
Far more than browser history, which is merely the most visible one. Sending from a computer or a phone typically leaves seven distinct deposits, and deleting them one by one only makes sense if you know about all of them.
| Trace | Where it sits | Default lifespan | Deletable |
|---|---|---|---|
| Browsing history | Browser | Months | Yes |
| Cookies and the site's local storage | Browser | Days to years | Yes |
| Saved form fields (the number you typed) | Browser autofill | Indefinite | Yes |
| Screenshot of the message | Photo gallery | Indefinite | Yes, + trash |
| Confirmation notification | Notification centre | Hours to days | Yes |
| Delivery-receipt email | Inbox | Indefinite | Yes, + trash + spam |
| Automatic backup (cloud) | iCloud, Google One, manufacturer backup | Depends on the plan | Partially |
The trap lies in the last two rows. You delete a screenshot, and it goes into a "Recently deleted" album where it stays for thirty days. You empty an inbox, and the delivery receipt remains in the trash. And if the automatic backup ran in the meantime, a copy of the device's earlier state exists elsewhere, beyond the reach of your local deletions.
In what order should you clean up?
- Close the session first on the service you used, before any cleaning: an explicit sign-out rather than simply closing the tab.
- Delete the screenshot, then empty the recently deleted items album.
- Deal with your inbox: the receipt message, then the trash, then the "sent items" folder if you forwarded anything.
- Clear the history and cookies for that site, not the whole browser: a completely empty history over a specific period is, in itself, a clue.
- Check autofill: numbers typed into a form often stay there. Browser settings → autofill data.
- Leave backups alone if you don't understand how they work: abruptly disabling an iCloud or Google backup can cost you something else.
If you find yourself doing this housekeeping regularly — for professional reasons, for instance when writing to clients without giving out your personal line, as detailed in our guide on writing to a client without giving out your personal number — the best hygiene is not cleaning but separation: a dedicated browser, or a dedicated device. A paired spare smartphone with no personal account, or even a simple feature phone kept for this purpose, solves the problem upstream: there's nothing left to clean because there's nothing to hide on that device.
What does the sending service keep, and for how long?
A sending service retains, at a minimum, the items required for its operation and its liability: timestamp, recipient number, content passed to the carrier, connection IP address. The GDPR does not forbid this retention: it requires that it be time-limited, documented and justified.
This is one of the most stubborn misunderstandings about anonymity by text message. "Anonymous" describes what the recipient sees; on the provider's side, you are a user identifiable through technical data. The CNIL notes on its website that an IP address is personal data, and that processing it must rest on a legal basis and a defined retention period. We set out this interplay in detail in anonymous texts and the GDPR: anonymity is not the absence of rules.
What you can do in practical terms:
- Read the privacy policy before sending, not after. Look for three words: "period", "retention", "recipients".
- Exercise your right to erasure (Article 17 of the GDPR) with the provider. It applies, but not in absolute terms: a data controller may refuse if retention is necessary to comply with a legal obligation or to establish abuse.
- Refer the matter to the CNIL if the provider does not reply within the one-month deadline set by the regulation.
And the confirmation email — should you ask for one?
A delivery receipt is useful: it proves the message went out, and it can help if you later need to show what you wrote — a point we address in how to build solid evidence. But it also creates a lasting document, in an account that bears your name, within a service that backs it up.
A simple trade-off: if the message is legitimate and something you'd stand behind (booking an appointment, alerting someone, reporting information), keep the confirmation — it protects you. If discretion is the main objective, forgo the receipt and instead note the essentials on an offline medium — a hardcover notebook is enough and syncs with nothing.
What do carriers keep, and can you have it deleted?
Nothing can be deleted on request at this level, and that's the most important part to understand. Under Article L. 34-1 of the French Postal and Electronic Communications Code, electronic communications operators retain certain categories of data for the purposes of criminal proceedings — notably civil identity data and information relating to traffic and location, for periods set by regulation, with one year being the usual order of magnitude for traffic data.
Three practical consequences:
Hiding your number is a display function. It acts on what the called party or recipient sees, never on what the network records.
- The #31# prefix does not create network anonymity. It asks the carrier not to pass on your number for display. The carrier, for its part, knows perfectly well who called. And for text messages, it simply doesn't work: the subject is covered in blocking withheld-number calls without missing a text.
- A judicial order lifts anonymity. At the request of a magistrate or an authorised judicial police officer, as part of an investigation, the retained data is handed over. Anonymity by text message holds against the recipient, not against the courts.
- Your own statements also keep a record. The usage details available from your carrier's customer portal may list sent messages. You cannot delete them; you can, however, know that they exist and who in your household has access to the customer account — the typical case being a family plan held in a parent's or partner's name.
In other words: serious deletion applies to levels 1 and 2. Level 3 cannot be cleaned, only anticipated — by choosing from the outset a channel and a use that won't expose you if someone ever takes a closer look. That's also why the question of the channel arises before sending, not after, as explained in the 7 checks to run before you send.
Should you delete, or should you keep?
There are situations where the instinct to clean up is a mistake. If your message is part of a conflict — a neighbour dispute, a separation, a professional disagreement — destroying your own traces deprives you of the only item able to show that you wrote once, at a given time, and exactly what you wrote.
So distinguish between two needs that are often confused:
- Discretion towards the people around you: local cleaning, separate devices, no delivery receipt.
- Legal safety: keeping a dated, offline copy of what you sent.
The two are compatible on one condition: that the copy does not live on your everyday device. An encrypted USB stick stored elsewhere, or an encrypted external hard drive for larger volumes, does exactly that job. You then get what is most often missing: nothing to find on the phone, everything to produce if needed.
Two final safeguards. First, deletion regularises nothing: if the message amounted to harassment within the meaning of Article 222-33-2-2 of the French Criminal Code, or to threats, removing your traces erases neither the offence nor the records kept elsewhere. Second, a device never forgets completely — an ordinary deletion marks the space as reusable without immediately overwriting the data. If you have to part with the device, what counts is a full factory reset, not sorting through file by file: the method is described in buying, reselling and wiping without giving yourself away. Any reader mildly curious about these mechanisms will find in a plain-language book on cybersecurity plenty to explain why "deleted" almost never means "gone".
Summary: the three questions to ask yourself after sending
- Who has access to the device I used? If the answer isn't "only me", local cleaning is the priority — and next time, switch devices rather than clean up.
- Do I need proof of this message? If so, keep it offline; if not, don't request a receipt.
- Could my message withstand being read by a judge? If the answer is no, the problem isn't the trace, it's the message.
Frequently asked questions
Is clearing my browser history enough to erase an anonymous text?
No. History is only one trace out of roughly seven: the site's cookies, saved form fields, notifications, any confirmation email, screenshots and automatic backups all remain. And no local action affects the data retained by the carrier.
Can the recipient find my number afterwards?
No, not on their own. Neither a private individual nor a commercial caller-ID service has access to a carrier's connection data. Only a judicial order, as part of an investigation, can lift that anonymity. We spell out what is visible and what isn't in who is the sender of an anonymous text?.
How long is the data from a sent message kept?
On the sending service's side, the period must appear in the privacy policy and varies from one provider to another. On the carrier's side, retention follows Article L. 34-1 of the French Postal and Electronic Communications Code, with one year as the order of magnitude for traffic data.
Can I ask an SMS sending service to erase my data?
Yes, under Article 17 of the GDPR, with a reply expected within one month. The provider may nonetheless refuse if retention is necessary to comply with a legal obligation or to handle abuse. If there is no reply, you can lodge a complaint with the CNIL.
Should I erase my traces if I received a reply?
Not necessarily — and it is often inadvisable: a two-way conversation is precisely what attests to a consented exchange. How these exchanges work is explained in anonymous texts with replies: how does it work?.
Public sources consulted on 28 October 2026: Légifrance (criminal code, postal and electronic communications code, GDPR), CNIL (IP address, right to erasure, retention periods), Arcep, service-public.fr, cybermalveillance.gouv.fr. To send a message without disclosing your line, see the sending page and the guide send an SMS without giving your number.
