Exploring Composability in Blue Sky

From the outside, Bluesky may seem like a Twitter clone. But anyone who’s close to the technology — and the team — knows that they’re building something much deeper: they’re rethinking the internet’s architecture to create a more flexible, user-centric web.

Bluesky’s CTO Paul Frazee is the perfect person to explain all this, as he’s fantastic at tying technical concepts to their practical application and wider impact. In this interview with Mike McCue, recorded live at the Fediverse House at SXSW 2025, Frazee unpacks Bluesky’s first principles, what makes AT Protocol different from ActivityPub, why identity portability is a radical shift, and how decentralization could lead to more humane social spaces.

Other highlights include:

• Bluesky's growth spike and architecture first principles
• The challenges of bridging between federated networks
• What it means to build for composability
• How stackable moderation works
• Paul's take on full federation 
• Why this is a greenfield moment for developers 
• Bridging cultural echo chambers

Mentioned in this episode:

• Beaker Browser post-mortem

🔎 You can find Paul on Bluesky @pfrazee.com. 

✚ You can connect with Mike McCue all across the social web, including on Bluesky @mmccue.bsky.social.

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