Twitter (now X) formally allows signup with just an email — and then locks the fresh account minutes later with «confirm your identity», solvable only by SMS. In practice a phone number is mandatory for any usable X account. A virtual number from Get-SMS receives that code, keeping your personal number away from the platform and letting you run separate accounts for projects, bots (within X rules), or regional content.
X verifies numbers both at signup and at random «unusual activity» locks afterwards. The first check is the important one: once the account has some history, locks become rare unless the account behaves like spam. If a number is rejected during signup, that pool is temporarily rate-limited — cancel free of charge and take a neighbouring country.
Age the account before automation or bulk following: X's spam filters weigh account age heavily. Set a profile picture and bio immediately — blank profiles are locked first. If you plan to develop with the X API, note that the developer portal may ask to re-confirm the phone; a 30-day rented number covers the whole onboarding period. US and UK numbers show the best first-try rate; Indonesian numbers are the budget option that still passes reliably.
Note that a verified phone is also X's prerequisite for several account-level features: enabling two-factor authentication, applying for monetisation, and raising API rate limits all require the phone check to have been completed at least once. The virtual number covers this requirement the same way a physical SIM would.