It’s been testing it over the past couple of months, and today, Facebook has made its new Login Connect with Messenger available to all businesses.

As you can see in this sequence, with this new update, businesses will now also be able to add a Messenger connection opt-in as part of their Facebook Login process, providing another way to maintain customer connection, and amplify promotions with interested users.
The addition aligns with Facebook’s broader release of a range of new messaging and direct connection features for brands, which will provide more ways for businesses to give each user more personal focus through its apps.
As explained by Facebook:
“With this new feature, businesses are able to build better relationships by providing stronger customer care and more tailored engagement through the Messenger Platform.”
Direct connection has become increasingly important given Apple's recent ATT update, which now prompts iOS users to allow, or disallow, data tracking in all apps. As more people choose to opt out of tracking, that reduces the insight available for ad targeting - which could make direct connection tools like this even more valuable as a means to ensure you're able to get your promotions and awareness efforts in front of the right people, at the right time.
And it has seen strong response – in initial testing, Facebook noted that:
"We’ve seen more than 70% of users opt in to messaging with businesses that enable Login Connect with Messenger. This creates a vital source of new customer conversations for businesses looking to double down on customer engagement through the Messenger Platform."
Of course, brands do need to be mindful of such connection, and the privileged access it provides. Spamming people's messaging threads is far more intrusive than social ads, so this can easily be abused. But used in moderation, and with user interests in mind, ideally through proper segmentation, this could be a highly valuable process, worth considering in your connection flow.
In addition, Facebook also notes that 75% of adults want to communicate with businesses via messaging.
Personalized connection to interested users, through the platform they’re already engaging on. For some, that could be significantly more valuable than regular paid outreach.
Developers can check out the full documentation on the new process here.