Last Week in the ATmosphere – 2025feb

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Last Week in the ATmosphere – 2025feb.b

Welcome to this week’s edition of all the news that happens in the wider ATProto ecosystem. This edition is somewhat more technical, next week I’ll focus again on Bluesky and the growing ecosystem of video and image apps around it.

For the people who are less interested in the technical side, I think some of the main news of this week is still relevant: Chatting app Roomy shows that you can use only a few parts of the ecosystem and combine it with other protocols to build apps. And Microcosm shows that the network infrastructure can be even more modular and accessible than it has been so far.

The News

Roomy is a new P2P public group chat platform, build on both ATProto and Automerge. The project is currently in public alpha testing. Roomy has gotten funding from the ATProto Skyseed fund, and is build by the same people who are also building Weird. Roomy is not the first group chat on ATProto, last fall Picosky released an AppView for chatting on ATProto as well. What makes Roomy different is in the combination of using both ATProto and Automerge: ATProto is used for identity and logging in, and data is stored (in encrypted form) on your PDS. Automerge is used for the actual chatting itself. Automerge uses conflict-free replicated data types (CRDTs) to ‘merge’ everyone’s chat messages into a single chat room, even when other people are offline. What is most interesting to me about Roomy is that it shows that building on ATProto does not have to mean using all the components of the system. Instead, parts like the identity system can be used and combined with other protocols to build products. Another example of this is stream.place, a streaming platform which also integrates with ATProto by using the identity part of ATProto, while using other systems for the actual video streaming part.

Microcosm is an open source and self-hosted JSON API to an index the entire ATProto network, with records of all PDS record back-links. This allows anyone to write queries against it, for things like ‘how many likes did this post get’, and ‘who are all the followers of a DID’. In effect, this is a partial backend of an ATProto AppView: The Bluesky AppView listens to the firehose to get all updates, and creates an internal database that keeps track of these things like ‘how many likes does a post have’. With Microcosm, this part of the AppView is now split into a separate service, called Constellation. This service can index the entire global network and still run of a Raspberry Pi. That this type of service is now available as both API and for selfhosting means that other ATProto apps can also take advantage of it, an early example that uses Constellation is Skyblur. What is interesting to me is that it shows that it is possible to split ‘AppViews’ into multiple components that can be reused, making it more accessible to run apps on global scale without having to run a large infrastructure. Bluesky engineer Bryan Newbold says that this type of generic API/service as an original design goal for Bluesky’s Big Graph Server. In later designs this got scaled down to a more simple Relay. Now other independent developers can bring such services to the network anyway, without depending on Bluesky.

Lexidex is a web index of all the different Lexicons that are used on ATProto. It is part of a bigger proposal regarding Lexicon resolution that Bluesky is working on. With the new proposal, DIDs can now claim ownership over a Lexicon via DNS record, similar to handle validation. Only when a DID has properly claimed ownership over a Lexicon it will show up on Lexidex. For seeing all Lexicons and how often they get used, I can recommend this dashboard, which keeps track of all Lexicons.

Bluesky PDF uploader is a tool to upload a PDF file to your PDS, which then automatically gets posted to Bluesky. It follows a trend of people exploring how you can use the PDS to store arbitrary files, such as with ATFile. In general I think this space is hugely under-explored, and this simple PDF uploader tool is a good illustration of what is possible on an open protocol where everyone has a server that can store personal data.

MuteSky is a site that allows you to manage mute words in bulk. MuteSky has lists of thousands of terms, sorted by category, allowing people to easily manage lots of different mute words. I think sites like MuteSky point to what is possible, if people want to filter out and don’t see specific types of content, it helps if others have already done the work of selecting the words to filter out. However, one of the more difficult parts of effective filtering via mute words is selecting all the different misspellings of words that people use. If someone does not want to see content about Elon Musk, effective mute filters would also have to add terms like ‘elmo’ or ‘el*n’. Those variations and deliberate misspellings is what makes effective muting difficult, and it is a feature that MuteSky currently does not provide.

DrawAt is a collaborative canvas for people to draw upon, build on ATProto. You log in with your ATProto account and see a shared canvas that you can draw on. It differs from other shared ATProto canvas drawings like Blue Place in that your drawing itself is not stored on your PDS. It does allow you to draw as much as you want, where Blue Place is for placing individual pixels. Pinksea.art is another place to draw on ATProto; this Oekaki board gives you your own place to draw on.

ATProto on Glitch is an app for Glitch to get people familiar working with ATProto. Glitch is a platform for building and hosting web apps, and allows people to easily copy and remix other apps. ATProto on Glitch does not listen to the firehose, but does allow people to read and write data using the API client, as well as making their own custom lexicons.

rsky is an alternative PDS implementation by Blacksky creator Rudy Fraser, which has just taken another big step closer towards completion. Blacksky is working towards a full independent implementation of all their ATProto infrastructure. Millipds is another example of an from-scratch PDS implementation.

Atproto-pictures is a simple image CDN for ATProto, build by Bluesky developer Samuel Newman. So far, other apps on ATProto seem to have mainly used Bluesky’s CDN, and with this tool they can now easily run their own CDN.

On 19th february will be the virtual DWeb Meetup: Bluesky & Beyond, for both Bluesky and ATProto. It will feature talks by Bluesky engineer Bryan Newbold, Boris Mann who organises the upcoming ATmosphere conference, and Mallory Knodel of the Social Web Foundation. The meetup will be on February 19, 2025 11:30am PT, and is free to attend.

PDSls is an excellent tool for browsing and managing ATProto PDS data, and the tool has gotten some more updates recently. It can now query individual labels by labelers, SubscribeRepos on the firehose, and a Jetstream viewer with filtering options.

Bryan Newbald shared some more thoughts how Bluesky is thinking about implementing private data on ATProto. It helps give an idea of how Bluesky might approach the problem, although Newbold also stresses that Bluesky is not fully committed to the proposed solutions yet, and that these are early design discussions. Bluesky will finish other work on ATProto first before giving private data more attention, such as auth scopes and tweaks for a cheaper relay.

The Links

That’s all for this week, thanks for reading! You can subscribe to my newsletter to receive the weekly updates directly in your inbox below, and follow this blog @fediversereport.com and my personal account @laurenshof.online.

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