Twitter SMS on X today is mostly about codes: X texts you to verify a phone number, reset a password and, for X Premium subscribers, log in with two-factor authentication. X says it doesn't charge for text messages, but your mobile carrier may, depending on your plan. If codes aren't arriving, X's first fix is to unblock texts from the 40404 number.
A lot of the old SMS features people remember are gone or limited, so here's what X's own help pages say about texts on the platform now, what you might pay, and how to fix the most common problem: the code that never shows up.
What X still sends by text message
| Text from X | When you get it | Who can use it |
|---|---|---|
| Phone verification code | When you add or update a phone number | Anyone adding a number |
| Password reset code | When you choose to reset by text | Accounts with a verified number |
| Two-factor login code | When you log in with text message 2FA | X Premium subscribers only |
| Temporary password | When an app or device needs your X password after 2FA is on | Accounts using 2FA |
| Login code on x.com | If you choose to request a code by text at login | Accounts using two-factor authentication |
Does X charge for SMS?
No. X says it won't charge you for text messages or for using mobile.x.com. Your carrier is a different matter, and X spells out how it treats texts from X the same as texts from anyone you know:
- On an unlimited texting plan, you won't be charged for X's texts.
- On a plan with a monthly text allowance, texts over that number are charged, whether or not they came from X.
- If you pay per message, your carrier charges you for every message X sends.
X also notes that standard rates apply when you add your phone, and that some carriers, even in the UK, treat X's long code as an international number and charge per message. If you're on a tight plan, check with your carrier.
Can you still post to X by text?
X's SMS page says that once your phone is verified, you can send your updates to its long code, +447624800379, but you won't be able to receive text updates from X on that number. It also says to check whether your specific carrier supports two-way service with X. In other words, getting your timeline by text isn't something to plan around.
Why your X verification code isn't arriving
X currently flags on its phone FAQ page that some people are having trouble requesting and receiving verification codes by SMS. Its first fix: if you've ever blocked texts from a 40404 number, unblock it and request the code again. Beyond that, these are the checks I'd run, in order:
- Unblock 40404 in your phone's messages or blocked contacts list, then request a new code.
- Confirm the number on your account is the one in your hand. X allows only one phone number per account, even on a dual-SIM phone.
- Ask your carrier about texts from X. X says to check whether your carrier supports two-way service with X, and some carriers treat its long code as international.
- Request the code again. A password reset code by text is valid for 60 minutes, so an older one may have expired.
- If you use the same number on several accounts, use your email or username to start a password reset instead, because X says the phone number route won't work when more than one account shares it.
If you're waiting on a code because something looks wrong with your account, my guide to two-factor authentication explains how the different methods work.
Text message 2FA is Premium only
This is the change that catches people out. Effective 20 March 2023, X stopped supporting two-factor authentication by text message for non-Premium accounts, and anyone with it switched on had to disable it to keep using the account. X adds that even for X Premium, text message 2FA may vary by country and carrier.
On a free account, the two methods left are an authentication app or a security key. An authenticator app is the simplest for most people (here's how to set up Google Authenticator), and X shows you a backup code when you finish, which you should save somewhere safe.
Want AI doing the heavy lifting in your marketing?
I build the systems that handle the boring 80 percent, so you get your week back. Done properly, with the human kept in.
How to add or change your phone number on X
- From the navigation menu, tap Settings and privacy.
- Tap Account.
- Tap Phone Number and verify your password. Tap Add if you haven't added one before, or choose Update number or Delete number.
- Enter the number and tap Next.
- X sends an SMS with a verification code. Enter it in the app and tap Verify.
Phone number rules worth knowing
- One account can only have one phone number attached.
- One phone number can be added to up to 10 accounts, and each still gets texts for password resets and login verification.
- If your account is inactive for 45 days or more and your number is added and verified on a new account, X may detach it from yours and notify you that the number was reclaimed.
- If a new number says it's already in use, it probably belonged to someone else before you. X says the previous owner has no access to your account.
My verdict
Treat SMS on X as a backup channel for codes, not a feature. Keep a current number on the account so resets work, unblock 40404 if codes stop, and if you're on a free account, move your login protection to an authenticator app. Texts are the route X itself has scaled back.
Should the worst happen, I've laid out the recovery route in my guide to getting a hacked X account back.
Frequently asked questions
Does Twitter charge for SMS?
X says it doesn't charge for text messages or for using mobile.x.com, but your mobile carrier may charge depending on your plan.
Why am I not getting my X verification code by text?
X says some people are having trouble receiving SMS codes, and recommends unblocking texts from a 40404 number if you've blocked it, then requesting the code again.
Can I use SMS two-factor authentication on X for free?
No. Since 20 March 2023 X only supports text message two-factor authentication for X Premium subscribers. Free accounts can use an authentication app or a security key.
How many X accounts can use one phone number?
X says you can add the same phone number to up to 10 accounts, but each account can only have one phone number attached.
