Founding Engineer

About Blacksky

Blacksky helps communities create virtual third places where members democratically govern the recommender algorithms and moderation policies that shape their space and soon will also pool funds as groups and send money peer-to-peer. Our behind-the-scenes infrastructure, built on the AT Protocol (the open protocol behind Bluesky), lets those communities scale to millions of people while staying accountable to the values of the people in them.

We used that tooling to build the largest Black community on the decentralized web, with more than two million users and the most robust protection against misogynoir and anti-Black harassment anywhere online. We were the first server on the protocol to open up account signups and migrations, a core promise of the protocol that nobody had made real, and we’ve since helped tens of thousands of people move their accounts off Bluesky’s servers onto our own. Now, through Acorn, we’re handing the same infrastructure to other communities, from Latine communities to networks of media-makers and storytellers, so they can grow the way we did.

The throughline: platforms that call themselves “digital public squares” answer to no community in particular, and too often cause harm in the race to get big. We’re proving you can be accountable to a specific community and still offer the familiar, large-scale social experience people actually want. Everything we build is open source, because the community should be able to outlive the company that started it.

About the Role

This is a founding engineering role, and a senior one. You’ll own large parts of the Rust systems that make all of the above run, working directly with our founder, with real ownership from day one. Depending on what the network needs, the work spans backend, systems, infrastructure, and product features.

It also goes deeper than implementation. The AT Protocol is still being written, and Blacksky helps write it. You’ll read, pressure-test, and weigh in on emerging specifications, then build them: permissioned data and spaces, community and group moderation, and private payments among them. You’ll own building e-cash mints and the payment systems around them, and you’ll represent Blacksky in standards venues, including the IETF and the broader AT Protocol community. This is a chance to shape the foundations of the open social web, not just build on top of them.

What You’ll Work On

• The Rust services behind our feeds, data, and APIs, and our e-cash mint and payment systems
• Reading, shaping, and implementing emerging protocol specifications (permissioned data and spaces, community and group moderation, private payments), and representing Blacksky in standards work, including the IETF
• Consuming and processing the network’s real-time firehose: high-throughput event streams that stay reliable and in sync across millions of accounts and billions of records, with a backfill that never really stops
• Applied cryptography across the stack, implementing (rather than inventing) the schemes our systems rely on: the signed, content-addressed data and commitments at the core of the protocol, the e-cash behind the mint, and end-to-end encryption for private spaces, including helping bring in outside efforts like Encrypted Spaces
• Performance and reliability of large Postgres deployments and the storage and caching around them
• The backend behind our moderation and safety tooling, including the labeling systems that keep the community protected
• rsky, our open-source Rust implementation of the protocol, and our contributions back to the open social web
• Forks of other open source projects in the atproto ecosystem

Who You Are

A senior engineer with deep experience (think 8+ years) building and shipping production backend, systems, or infrastructure software, with hard problems owned end to end. Strong in Rust, or strong enough in a systems language like C++.