Twitter users on Apple’s iOS can now sign up and pay for the service, which will give them the blue-tick badge next to their profile name on the platform.
The company said the service would expand to Android and the web version of the app for users in due course, but Twitter owner Elon Musk continues to face criticism over the controversial change.
Until now, the verification badge was only given to notable or high-profile accounts which Twitter had analysed and deemed authentic, but now the only barrier to clear is for a user to pay a £6.99 monthly subscription.
Mr Musk has argued that adding a paid tier to the platform will help weed out spam and fake accounts because they will not be willing to pay to get traction on the site.
Twitter Blue is also set to add a feature that will promote replies to tweets from verified accounts as a way of rooting out those not verified on the site as part of a range of other perks labelled as “coming soon” to the subscription.
But critics have warned it will enable a new wave of misinformation as bad actors sign up for the badge and then pose as public figures to spread false information.
Twitter has pledged to stamp out any fake or misleading use of the system and says it will not allow users to change their display name after receiving a badge.
Twitter’s online help pages say the definition of the blue checkmark is “changing” as part of the update.
“Until now, Twitter used the blue checkmark to indicate active, notable, and authentic accounts of public interest that Twitter had independently verified based on certain requirements,” the company says.
“Now the blue checkmark may mean two different things: either that an account was verified under the previous verification criteria (active, notable, and authentic), or that the account has an active subscription to Twitter Blue.
“Accounts that receive the blue checkmark as part of a Twitter Blue subscription will not undergo review to confirm that they meet the active, notable and authentic criteria that was used in the previous process.”
It adds that the changes are designed to “help reduce fake, untrustworthy accounts, and promote higher quality Twitter”.
For now, accounts verified under the old system are allowed to keep their own blue badges.
The new system has gone live for users on iOS in the US, Canada, Australia and New Zealand, alongside the UK.
The update comes after a chaotic day on the site on Wednesday as another form of verification – a grey tick and “Official” badge was rolled out, only for Mr Musk to “kill” it a few hours later, saying it was “an aesthetic nightmare”.
In response to the back and forth, Mr Musk tweeted: “Please note that Twitter will do lots of dumb things in coming months.
“We will keep what works & change what doesn’t.”