Guides

Texting and SMS guides

How texting actually works: forwarding messages, automatic replies, sending from a business number, international format, and what happens when a message will not deliver.

Reviewed by Sujan ThapaliyaLast updated August 19, 2026

Text messages travel over a different path from calls, which is why a forwarding rule that moves your calls leaves your texts behind, and why a message can show as delivered when it was never seen. These guides cover the mechanics and the business cases that depend on them.

Why do texts behave differently from calls?

They are separate services on the same number. Voice is a live connection set up and torn down for each call; a text is a store-and-forward message handed between networks. That single difference explains most of what surprises people about SMS.

Every row here is a support ticket somebody files each week.
Behaviour	Calls	Texts
Carrier forwarding moves it	Yes	No — forwarding is a voice feature
Works without cell signal	Only over wifi calling	Yes, in any app that sends over data
You learn it failed	Immediately	Often not at all
Blocked at the far end	Rings once, then voicemail	Sends normally and is silently discarded
Business registration required	No	Yes, for application-to-person traffic

What changes when a business does the texting?

Two things. Consent applies — the rules that govern calling a number govern texting it, including do-not-call handling and permitted hours. And carriers require application-to-person traffic to be registered against a brand and a use case, or they filter it, which is why business messages vanish while the delivery receipts look healthy.

Which guide do you need?

If a message will not arrive, start with the blocked-number guide. If you are trying to move messages somewhere — another phone, an inbox, a colleague — start with forwarding. If you are writing to customers rather than to one person, the business number and international format guides are the relevant ones.

Texting and SMS

Guides in this section

How to forward text messages to another number, phone or inbox

Carrier call forwarding does not move text messages — it is a voice feature. To forward texts you either turn on message sync between your own devices, use a third-party auto-forwarding app, ask your carrier whether they offer SMS forwarding, or move the number to a platform where messages arrive in a shared inbox.

How to set up an automatic text reply

iPhone has Driving Focus, which auto-replies only while you are driving, and Focus modes that can reply to chosen contacts. Android varies by manufacturer, with some builds offering scheduled replies. Neither handles business hours properly, which is why a scheduled auto-reply belongs on a business messaging platform.

How to text from a different number than your own

Get a second number and text from it: a business messaging platform, a second line on your existing phone, or a dual-SIM setup. Sending a message that displays somebody else's number is spoofing rather than a feature, and carriers filter it aggressively even where it is not unlawful.

What happens when you text a number that blocked you

The message sends normally and is discarded at the other end. You get no error, no bounce and usually no delivery report either way, which is why nothing on your screen distinguishes being blocked from a phone that is switched off. Delivery receipts are not evidence in either direction.

How to text over wifi when you have no signal

Messages sent through an app — iMessage, WhatsApp, a business texting platform — travel over data, so they work on wifi with no cell signal. Standard SMS between two ordinary handsets needs the carrier network, unless you enable wifi calling on the line, which carries SMS over wifi too.

SMS international format: how to write a number so the text arrives

International standard format is E.164: a plus sign, the country code, then the national number with no spaces, dashes or leading trunk zero. A UK mobile written 07700 900123 becomes +447700900123. That single form works from every country and every platform.

Frequently asked questions

Does call forwarding forward text messages?

No. Carrier call forwarding is a voice feature: it moves calls and leaves texts on the original handset. That is the single most common surprise when somebody forwards a line to hand it over to a colleague.

Can you text over wifi with no cell signal?

Yes, in any app that sends over data rather than the carrier's messaging service — including business texting platforms. Standard SMS between two ordinary handsets needs the carrier network unless wifi calling is enabled on the line.

Why do my business texts show as delivered but never get replies?

Usually carrier filtering rather than a delivery problem. Unregistered application-to-person traffic is filtered after the delivery receipt is issued, so the receipts look fine and nothing reaches anyone. Registration is the fix, not sending more.

Do consent rules apply to texting?

Yes. Texts are treated as calls for consent purposes, so the permission, do-not-call scrubbing, timing limits and opt-out handling you need to call a number all apply to messaging it.

Sources

Combating Spoofed Robocalls with Caller ID Authentication — Federal Communications CommissionThe STIR/SHAKEN framework, the attestation levels carriers sign calls with, and the mandate requiring providers to authenticate caller ID.
47 U.S.C. § 227 — Restrictions on the use of telephone equipment — Cornell Legal Information InstituteThe Telephone Consumer Protection Act itself — the consent requirements, calling-hours limits, and private right of action.
ITU-T Recommendation E.164 — The international public telecommunication numbering plan — International Telecommunication UnionThe international number format, the 15-digit maximum, and how country codes and national numbers compose.

Or run the phone system that does not need star codes

Routing rules, voicemail, recording and reporting against numbers you own, priced on what you use.

Get early access See products