SMS was never private, and what that actually means for you

SMS is the most widely supported messaging system on earth. Every phone has it, no account is required, and it works when nothing else does. It is also, by any modern standard, completely unprotected.

This is worth understanding precisely, because the useful conclusion is not "stop using SMS". It is "know which messages belong somewhere else".

What actually happens when you send a text

Your message leaves your phone over the mobile network, reaches your carrier's messaging centre, gets routed to the recipient's carrier, and is delivered. At several of those points it exists as readable text, and it is stored: for delivery retries, for billing, and for whatever retention period the law and the carrier require.

There is no end-to-end encryption anywhere in that chain. There was never meant to be: SMS was specified in the 1980s as a way to use spare signalling capacity, and confidentiality was not a design goal.

Who can read your texts

Being concrete is more useful than being alarming.

Your carrier and the recipient's carrier. They handle the message in plain text and retain it for a period.
Law enforcement with legal process. Access to stored messages is a routine and well-established procedure in most jurisdictions.
Anyone who compromises the network. SS7, the signalling protocol underpinning international routing, has known weaknesses that have been demonstrated repeatedly.
Anyone holding your unlocked phone. Usually the most realistic risk on this list.

Notably absent: random people nearby. The link between your phone and the tower is encrypted. SMS interception is not something a stranger in a café does.

What this means in practice

Treat SMS roughly the way you would treat a postcard: fine for most things, wrong for a few specific ones.

Reasonable over SMS: delivery notifications, appointment reminders, "running ten minutes late", the vast majority of everyday coordination.

Better somewhere encrypted: passwords and access codes, financial details, medical information, anything you would not want read out in a room you are not in.

The two-factor problem

The exception worth knowing about: SMS is still the most common second factor for logging in, and it is the weakest one in common use. SIM-swap attacks, where someone convinces your carrier to move your number to their SIM, are not exotic. They are a service you can buy.

If an account matters, move its second factor to an authenticator app or a hardware key. SMS 2FA is better than no 2FA, and worse than everything else.

Encryption on the wire and encryption at rest are different problems. SMS has none in transit. But the copy sitting in your phone can absolutely be protected, and on most devices that copy is the one an attacker will actually get at.

Where Textly sits in this

We cannot fix SMS. Nobody can; it would require replacing global carrier infrastructure. Any app claiming to make your texts end-to-end encrypted is either describing a different protocol or misleading you.

What we can control is the part on your device. The local message store is encrypted behind Android's hardware-backed keystore, tied to your screen lock. Nothing is copied to a server of ours. We do run one: it holds a number, a balance and whether your phone is still the default messenger. It has never held a message. And the intelligence that reads your messages runs locally, so understanding them never requires transmitting them.

That is the honest division of responsibility: the carrier owns the wire, and we own the device. We take the part we own seriously, and we do not pretend to own the rest.

And the messages you are paid for

One more line in that division of responsibility, because Textly now pays for answers.

A paid poll arrives in the Textly Thread, one conversation from us that is never an SMS, and is answered with a tap. It does not travel as SMS, so nothing above applies to it: it is not sitting in an operator's logs, and it is not readable by the network the way a text message is. The answer goes to us, because that is the transaction; the conversation it landed next to does not, because we have nowhere to put it.

Which is the same division as before, one step further. The carrier owns the wire. We own the device. And the only thing that leaves it on purpose is the answer you chose to give.