ChatGPT does not usually need a phone number: OpenAI's help centre says phone verification is not generally required to create an account or use ChatGPT. OpenAI does ask you to verify your phone number for your first API key on the developer platform, and it may ask when you open Codex in the ChatGPT desktop app. In some countries you can also sign up with a phone number instead of an e-mail.
When OpenAI asks for a phone number
| Phone number needed? | |
|---|---|
| Creating an account and chatting in ChatGPT | Not generally |
| Opening Codex in the ChatGPT desktop app | You may be asked |
| Your first API key on platform.openai.com | Yes |
| Any API key after the first | No |
| Phone-only sign-up, in some countries | Yes, the number is your login |
Per OpenAI's help centre, October 2026. OpenAI changes this often.
OpenAI states that an e-mail address or an authenticator app does not replace the phone step for Codex. If you sign in through a company SSO and are asked anyway, OpenAI asks you to contact its support with the exact error.
One number, up to three verifications
OpenAI counts how often a number has been used. A phone number can complete phone verification at most three times, across all accounts, and OpenAI says it makes no exceptions.
- The number cannot be changed. OpenAI offers no way to update it, for ChatGPT or the API.
- Deleted an account? For a consumer account that was not disabled for a rule violation, the number is freed after 30 days.
- “Too many signups with this number” can appear on a recycled number that someone else used before you. OpenAI names no workaround.
- Phone-only accounts reset their password by SMS, and only from a device that has signed in before.
Verification code not arriving
| Accepted by OpenAI | |
|---|---|
| A mobile number that receives SMS | Yes |
| Landlines | No |
| VoIP numbers and Google Voice | No |
| Premium-rate numbers | No |
OpenAI says these number types are often linked to fraud or abuse.
- Check the country The form starts on the United States. Pick your country first, then check every digit of the number.
- Look in WhatsApp In some countries the screen offers WhatsApp delivery. If you chose it, the code arrives there, not as a text.
- Do not wait for a call or e-mail OpenAI sends codes only by SMS or WhatsApp.
- Error on a supported number Contact OpenAI support and quote the exact error message.
Using a number you do not hand out
Some people would rather not link a personal number to an API account they use for a test project. For a one-time verification, such as the first API key, a temporary number receives the code instead.
- Fits: a one-off check that will not come back, on an account that also has an e-mail login.
- Does not fit: a phone-only ChatGPT sign-up, because the number is then your login and your password reset.
- Expect refusals: OpenAI turns away many virtual ranges, so choose a country with a good success rate and switch if nothing arrives after about two minutes.
The form opens on the United States; what is available there right now is on the page for US numbers for OpenAI. Claude asks at a different moment and has its own limits: see Claude phone verification.
Common questions
Do I need a phone number to use ChatGPT?
Usually not. OpenAI says phone verification is not generally required to create an account or use ChatGPT. Codex in the desktop app and your first API key are the exceptions.
Why is ChatGPT asking for my phone number?
Most often because you opened Codex in the ChatGPT desktop app or are creating your first API key. In some countries ChatGPT also offers sign-up with a phone number instead of an e-mail.
Can I use a Google Voice or VoIP number for OpenAI?
No. OpenAI does not accept landlines, VoIP numbers, Google Voice or premium-rate numbers.
How many OpenAI accounts can use one phone number?
A number can be used for phone verification up to three times. After that it is refused, with no exceptions.
Can I get the OpenAI code by call or e-mail?
No. Codes go out by SMS, or by WhatsApp where OpenAI offers it in your country.
Can I change the phone number on my OpenAI account?
No. OpenAI does not let you change or update the number, neither for ChatGPT nor for the API.