Use TwinNumber with ChatGPT.
Setting up or securing your own ChatGPT account? Use a real U.S. mobile number for sign-up checks and two-step verification codes, and read them in your browser.
- What we tested
- Receiving SMS verification codes
- Line type
- Mobile
- Last tested
- Oct 12, 2026
We re-test ChatGPT regularly and update this date.
What ChatGPT uses your number for
- Phone verification before you generate your first API key on platform.openai.com.
- A verification step that may appear when you open Codex in the ChatGPT desktop app.
- Optional multi-factor sign-in codes by text message or WhatsApp.
Add your TwinNumber on ChatGPT
- 01
Choose a number you'll keep
OpenAI doesn't offer a way to change or unlink the phone number on your account, for ChatGPT or the API.
- 02
Use a mobile number
Codes go out only by SMS or, where available, WhatsApp; landlines, VoIP and premium numbers aren't accepted.
- 03
Add SMS sign-in codes
For MFA, open Settings > Security and login, pick text message under Multi-factor authentication and enter the code.
Why the line type matters
AI and developer platforms often check whether a number is mobile, landline or VoIP before sending a code, and many turn VoIP numbers away. TwinNumber numbers are registered as mobile.
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Why does OpenAI ask for my phone number?
Phone verification isn't generally required to use ChatGPT, but OpenAI asks for it before your first API key and may ask when you use Codex in the desktop app. You can also add your number for multi-factor sign-in.
Can I change the phone number on my OpenAI account later?
No, OpenAI doesn't offer that option. A number can also be used for phone verification only up to 3 times, so verify with one you plan to keep.
Does a U.S. number give me ChatGPT where it isn't offered?
No. OpenAI asks for a mobile number from a supported country or region, and a U.S. number doesn't change where its services are available to you.
Do I need to live in the U.S.?
No. TwinNumber works from 150+ countries with just a browser and an internet connection.
Is TwinNumber affiliated with ChatGPT?
No. We test our numbers with popular services and publish the results. ChatGPT is a trademark of its owner.
What if a code doesn't arrive?
Request a new code, then check your inbox and notification settings. If it keeps failing, contact us and we'll look into it.
Ready for ChatGPT codes?
Join the waitlist and be among the first to get your U.S. mobile number.