Support for end-to-end encrypted messaging in ActivityPub has been stated as a long-term goal by the Social Web Foundation, but the network might be gaining support for it sooner than anyone expected. Ben Pate, the lead dev of Emissary, posted to the network earlier this week:

Since January, Bonfire and Emissary have been working on true E2EE in ActivityPub, using the MLS protocol — which is a successor to Signal protocol with better support for very large groups.

Anyway, here’s today’s progress video of where I am. Here’s what works: exchanging public keys, creating groups, sending/receiving messages and replies, and realtime notifications.

There’s a lot more to do. We’re planning on general availability in June, so right now we’re about 1/3 of the way into the project.

Funding for this feature was secured through the Sovereign Tech Fund, with leadership provided by the Social Web Foundation. Emissary and Bonfire are both working on this project, and are due to provide deliverables by June 2026. The result of this work will eventually provide a clear standard in a future version of the ActivityPub protocol spec. A December 2025 draft of the existing spec can be read here.

A Quick Demo

Ben was nice enough to record a quick demo for people to get a visual representation of where things are currently, and what support for encrypted messaging looks like.

What’s Next?

For now, implementers are working hard to iron out wrinkles and resolve outstanding points of ambiguity. The demo above already showcases a working product, although a number of client-side bells and whistles could be added for things like read receipts, native support for different content types, and autocomplete for looking up contacts.

The spec currently appears to propose an idea that client implementers could leverage end-to-end encryption through a future version of the ActivityPub API. While the proposal spec is relatively fleshed-out, it would benefit greatly from community feedback.

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