Have you ever encountered this situation while using Codex, where you need to bind a foreign phone number to receive a verification code before you can continue logging in?

There is a +86 option in the dropdown list, but after entering the number, it shows as invalid (it seems there is no +86 option anymore, though there was one before).

SMS Verification Platforms

The current common solution is to use an SMS verification platform, receiving the verification code via a virtual number provided by the platform https://github.com/fazgal0/free-sms-receivers

Some verification platforms can provide a number with a one-month validity period. Any SMS verification issues within that month can be resolved.

If your Codex stays logged in on the same device without logging out, and you don't encounter risk-control scenarios requiring a second login during use, you can use this method.

Applying for a UK giffgaff Phone Number

The downside of using a verification platform is that if a second verification is needed, you can only use the phone that received the verification code last time. Moreover, Codex currently does not support changing the phone number. If a second login is required, your account is practically useless (the author has already lost one account this way).

The best way is to apply for a foreign phone number. Whether for Codex or other scenarios requiring foreign phone verification, it can be perfectly resolved. After some research, the easiest to apply for is the UK (+44) giffgaff. The benefits are as follows:

• A real carrier number, not a VoIP number like Google Voice
• No real-name registration required domestically, direct payment with Visa
• Easy to keep active: just send a text message every six months for £0.3 to keep the number

Buying a Physical SIM Card

Buy a physical giffgaff SIM card directly from JD.com. The official giffgaff platform does not support shipping to China, and major platforms have also blocked the giffgaff keyword. Currently, JD.com is the only channel to purchase one; search for "UK gg envelope".

If you don't want to buy a physical SIM, you can also apply for a giffgaff eSIM.

Overseas Version Phones Support eSIM

If you have an overseas version phone that supports eSIM, you can directly download the giffgaff App. After registering and logging in, apply directly. When choosing a plan, scroll all the way to the bottom and select the plan with no monthly fee. For the specific process, you can refer to the application method for domestic phones below.

Domestic Phones Do Not Support eSIM

To prevent domestic users from applying, giffgaff checks if your phone supports eSIM before applying for one. Therefore, you need to use an Android phone to download a modified APK to apply. The modified version hardcodes the eSIM variable to true.

Download link: https://drive.google.com/file/d/1llkIojBFCuqpQcr0ObEG-EgbP_UUfopq/view

After downloading, register and log in first, then follow the process below:

The minimum top-up amount to activate the number is £10. Choose credit card payment. The default options here are only Visa and Mastercard credit cards. You can fill in your own name for the payment information, and fill in the rest according to the template.

After successful payment, you will receive the eSIM phone information in your Outlook email. Then download the eSIM activation code. The activation code is only valid for 24 hours. Normally, it will be automatically copied to the clipboard. After the number is activated and used, you can receive a welcome text message from giffgaff.

Because domestic phones do not support eSIM, you need to buy a blank eSIM card. Use a card reader to download the eSIM onto the blank card, then insert the card for use. This can be bought directly on Taobao.

The eSIM activation code obtained after application is only valid for 24 hours, so it's best to apply after the card reader and blank card have arrived.

Tips for Keeping the Number Active

After using giffgaff, first turn off international roaming, otherwise the £10 will be used up in a minute. The phone needs to be actively used (send a text, make a call, use data) once every six months to keep the number active. The safest method is to send a text message. Domestic phones might fail to send, so you can send it directly to your own giffgaff number. As long as you see a normal deduction in the giffgaff app, the number has been successfully kept active. Top-ups are also done within the app. £10 should be enough to keep the number active for 20 years, barring any unforeseen issues.

Off-Topic

After starting formal work, I rarely have time to browse Juejin and write things. My last update was a year ago when I first joined ByteDance as a campus hire. I have since left ByteDance and gone to Didi. If I have time, I will continue to share some practical tips with everyone. Please forgive my slightly degraded writing style.