ChatGPT by Text: SMS, WhatsApp or iMessage?

Nothing, because it does not exist as an official OpenAI feature. There is no short code, no ten digit number, and no toll free line that OpenAI publishes for plain SMS access to ChatGPT. What you will find if you search for "text ChatGPT" are third party apps and bridges that call the ChatGPT API on the back end and hand you a phone number on the front end, and those are genuinely useful products, just not ChatGPT itself. Before you point a business at one, ask who owns the number, what happens to the conversation data, and what happens to your setup if that vendor shuts down or changes its terms, since none of those answers come from OpenAI's own policies. If your business already needs a texting number that an AI agent answers from, building that yourself with a platform you control removes the dependency on a vendor OpenAI never vetted in the first place.

A ChatGPT Pro 100 or Pro 200 subscription, a United States phone number, and an iPhone with iMessage already turned on, or an Android phone with RCS already active in Google Messages. OpenAI launched this feature on October 30, 2026 under a persona named Dot, and it is a genuinely different shape of product than the WhatsApp contact: you link your own phone number from Dot's profile inside the ChatGPT app, and Dot can then text you first, not just answer when you reach out, sending text, photos and voice memos and asking you to confirm anything that needs approval through a link back into the app (techtimes.com). Access is rolling out gradually to eligible Pro accounts rather than everyone at once, and it is explicitly limited to the United States, excluding the European Economic Area, Switzerland and the United Kingdom.

The privacy picture is the part worth slowing down for. Apple's end to end encryption on iMessage runs between Apple IDs, but Dot's texts arrive through a third party vendor called Linq, registered as a business sender rather than a personal Apple ID, so whether that specific path carries full iMessage encryption is a detail OpenAI has not made public. On the Android side, RCS business messaging uses transport layer security rather than the device to device end to end encryption that RCS normally offers between two people, because business messaging is deliberately excluded from that encryption spec. OpenAI's own documentation reportedly tells users to use caution with sensitive information sent through this channel, and a security writeup on the launch put the risk plainly: a Dot connected to your calendar, email or financial accounts is a more valuable target than a general purpose chatbot, and whether OpenAI's security testing specifically covered the Linq relationship has not been disclosed (techtimes.com).

Work through the question in order, because each step rules out at least one of the three channels before you get to the next one.

1. Write down who actually needs to reach the assistant. A single person reaching it from their own phone and a list of customers texting a shared business line are two different products, not one, and the rest of the decision follows from which of those you are actually building.
2. Check which country each relevant phone number is registered in. A United States number rules out WhatsApp today, while any number outside the United States rules out Dot's iMessage and RCS feature, so this one check alone often leaves only one of the three channels still standing.
3. Check your budget tier honestly. WhatsApp access is free once it is available to you, SMS has no official path at any price because it does not exist, and Dot requires an active Pro 100 or Pro 200 subscription for every single person who uses it, not one shared business seat.
4. Decide what the assistant actually needs to see. A one to one personal connection with no access to anyone else's inbox, which is how Dot is built, is a very different shape of product from a shared number with full conversation history, tagging, and CRM sync across a whole team.
5. Run a plain privacy gut check. Ask whether you are comfortable with this conversation's content passing through a vendor's relay that is not the platform's own first party infrastructure, given what OpenAI itself says about Linq and sensitive data.

If what you actually want is a business number that customers text and an AI agent answers from, none of the five steps above end in texting ChatGPT directly at all. That is a job for an iMessage bot you build or run on your own number, with whichever model you pick working behind it rather than a single vendor's consumer feature. Teams already running inside GoHighLevel and weighing iMessage against plain SMS for that specific setup have a more detailed next read in Beam's own comparison of iMessage and SMS inside GoHighLevel.