OpenAI asks for phone verification in two situations: when you generate your first API key on the developer platform, and for some new ChatGPT sign-ups in certain countries. The code arrives by SMS or, where available, WhatsApp. One number can be used for this verification at most three times, landlines and VoIP numbers are generally not accepted, and the verified number can't be changed later. If your code doesn't arrive or the number is rejected, the checks below solve most cases.
When OpenAI asks for phone verification
- Your first API key. According to OpenAI's help center, phone verification is required on platform.openai.com before you generate your initial API key. Later keys don't need it again.
- Some ChatGPT sign-ups. OpenAI has rolled out phone verification for new ChatGPT users in a list of countries, including the United States, the United Kingdom, Germany, France, Spain, the Netherlands, Poland, Japan and India.
The purpose is the same in both cases: to make it expensive to create accounts in bulk and to tie each account to a real person.
The rules that matter before you start
| Rule | What it means for you |
|---|---|
| Codes by SMS or WhatsApp only | No email or voice call option; check WhatsApp if SMS doesn't arrive |
| One number, up to three verifications | A number used for three OpenAI accounts can't verify a fourth |
| Deleted ChatGPT accounts free the number after 30 days | Only if the account wasn't disabled for policy violations |
| The verified number can't be changed | Choose the number carefully; you can't swap it later |
| Landlines, premium and VoIP numbers | Generally rejected; use a mobile number that receives SMS |
| Supported countries only | OpenAI does not offer ChatGPT and the API in every country |
The full list of rules is in OpenAI's phone verification help collection. The VoIP rule is the one that surprises people most; our explainer on non-VoIP vs VoIP numbers shows why apps filter them.
OpenAI phone verification not working: fixes
- Check the country and format. Choose your country in the dropdown and type the number without its leading 0.
- Look in WhatsApp. Where WhatsApp delivery is available, the code may arrive there instead of as an SMS.
- Wait before requesting again. Several requests in a row can trigger a temporary block. Leave it for an hour, then try once.
- Read the error message. "Already linked to the maximum number of accounts" means the three-use limit is reached; only a different number helps.
- Use a mobile number. If the number comes from a calling app or a fixed line, replace it with a mobile number.
- Try a clean browser session. Ad blockers and privacy extensions sometimes break the verification form; a private window without extensions rules this out.
- Contact OpenAI support. If none of the above works, use the chat in OpenAI's help center and include the exact error text.
Using a one-time number for your API key
If your own number has reached the three-use limit, or you prefer not to tie a personal number to a developer account, a one-time mobile number can receive the code. On smsvar.com you choose OpenAI as the service and a country, see the price before you buy, and the code appears on your order screen. If nothing arrives within 20 minutes, the order is cancelled and the fee goes back to your balance automatically. Prices per country are on our prices page; if you are new to this, start with how receiving SMS online works.
Two points to keep in mind. First, OpenAI doesn't let you change the verified number later, so a temporary phone number should never be your account's only way back in; secure the account as described below. Second, a foreign number does not change where you are: OpenAI's services are available only in supported countries, and its terms apply to you wherever your number comes from. Don't use extra numbers to create additional accounts and get around usage limits; OpenAI disables accounts for that.
Secure your OpenAI account after verification
- Turn on multi-factor authentication with an authenticator app in your account's security settings.
- Keep your login email accessible. Email is how you recover the account, not the phone number.
- Protect API keys. Store them in environment variables or a secret manager, never in public code, and set a monthly usage limit.
Frequently asked questions
Why does OpenAI say my number is linked to the maximum number of accounts?
Because the number has already been used three times for OpenAI phone verification, which is the maximum. This includes accounts created by other people if the number is shared or recycled. The only solution is to verify with a different mobile number.
Can I get the OpenAI code by email or a phone call?
No. OpenAI sends verification codes only by SMS or, where it is available, WhatsApp. If the SMS doesn't arrive, check WhatsApp on the same number, wait a while before requesting another code, and make sure the number is a mobile number.
Can I change the phone number on my OpenAI account?
OpenAI's help center states that changing the phone number on an account is not supported. That is why it is worth choosing the number carefully and securing the account with multi-factor authentication and a reliable email address.
Do I need to verify my phone for every API key?
No. Phone verification is required only before you generate your first API key on the platform. Additional keys in the same account can be created without verifying again.
Ready to verify? Open our virtual number page, choose OpenAI and a country, and you'll see availability and the price before you pay.