Tumblr to add support for ActivityPub, the social protocol powering Mastodon and other apps

Tumblr will add support for ActivityPub, the open, decentralized social networking protocol that today is powering social networking software like Twitter alternative Mastodon, the Instagram-like Pixelfed, video streaming service PeerTube, and others. The news was revealed in response to a Twitter user’s complaint about Mastodon’s complexities. Automattic CEO Matt Mullenweg — whose company acquired Tumblr from Verizon in 2019suggested the user “come to Tumblr” as the site would soon “add activitypub for interconnect.”

“Don’t stress,” he said, before clarifying that Tumblr first has to deal with the waves of new users coming in right now from Twitter but that support for “interop and activitypub” were due to come “ASAP.”

In short, this announcement means Tumblr would move from being only a niche blogging platform to becoming a part of a larger, decentralized social network of sorts — and one whose user base has grown in size in recent days as people flee Elon Musk’s Twitter in search of new communities.

The ActivityPub protocol, its website explains, provides a client-to-server API for creating, updating, and deleting content, as well as a federal server-to-server API for delivering notifications and subscribing to content. In practice, this means that Mastodon users can interact with and follow users on other instances (independently run nodes) and on other social apps (like PeerTube), which also support the implementation of ActivityPub. It makes for a web of social networks where users can find and follow each other without having to set up new accounts on each new service.

This is the opposite approach to today’s “walled garden” social networks, where a post on one platform can’t be viewed by those on others, unless you re-upload or repost the content directly or share a link to the other site where the content can be found.

If Tumblr were to add ActivityPub support, it means users on Mastodon could follow Tumblr users’ posts from their own Mastodon instance — without having to use the Tumblr app. It could also provide Tumblr users with an entry point into the so-called fediverse¬†without having to face some of the complexities that are involved with signing up for Mastodon for the first time.

Tumblr was already benefiting from the Twitter exodus, having grown its U.S. app installs 7% week-over-week from the week prior to the acquisition and the 7 days after, data.ai had reported earlier this month. And, as of 12 days after Twitter’s acquisition, Tumblr’s worldwide downloads surged 77% to 301,000 up from 170,000 in the 12 days before the acquisition, Sensor Tower recently said.

Mullenweg later offered a glimpse into Tumblr’s metrics, noting to The Atlantic that iOS downloads of the Tumblr app were up 62% the week after Musk took over Twitter.

But even before Musk took Twitter’s helm, Mullenweg had been thinking about how Tumblr could better compete with Twitter in the future.

“I just want there to be an open alternative, I want you to be able to choose your algorithm…we’re trying to make Tumblr a space for art and artists…,” he had said earlier this year, one where “you’re not doomscrolling, you’re joy-scrolling.”

More recently, Mullenweg has been trying to directly recruit former Twitter employees to come work for Automattic, setting up a dedicated website for the purpose.

Automattic, we should note, already has some experience with ActivityPub.

In addition to Tumblr, Automattic runs the blogging service WordPress.com and contributes to the open source WordPress blogging software platform. The latter today offers an ActivityPub plug-in for self-hosted WordPress sites. This allows a WordPress blog’s readers to follow their posts on Mastodon and other federated social platforms. One could imagine a similar scenario for Tumblr, if ActivitiyPub support was added.

Mullenweg did not offer an ETA as to how “ASAP” this support would be added.

Tumblr was not able to provide an immediate comment when reached.