The Fly Blog is the engineering blog of Fly.io, a cloud platform that runs applications close to users on the edge. It's written by their engineers and covers everything from deploying apps to building AI agents. If you're curious about modern cloud infrastructure or want to see how a startup thinks about distributed systems, this is a great read.
FlyThe Fly Blog
The Fly Blog is the engineering blog of Fly.io, a cloud platform that runs applications close to users on the edge. It's written by their engineers and covers everything from deploying apps to building AI agents. If you're curious about modern cloud infrastructure or want to see how a startup thinks about distributed systems, this is a great read.
“Building and running distributed apps on Fly.io's edge cloud.”
Read this when you want to understand practical edge deployment, SQLite at scale, or integrating AI with cloud infrastructure.
Skip it if you need generic cloud tutorials or vendor-agnostic deep dives.
Compared to the AWS Architecture Blog, this one is more opinionated, startup-focused, and deeply tied to Fly.io's own platform.
What this is
As told for the tourist
Start Here
A recommended reading path through the code
Start Here
A recommended reading path through the code
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What's inside
8 sections of the codebase
Posting History
Activity over time
The Archive
Every post, searchable and filtered
Unfortunately, Sprites Now Speak MCP
4mIntroduces Sprites as disposable cloud computers for running agents with instant startup and durable filesystems.
Litestream Writable VFS
5mDescribes the new writable VFS feature for Litestream, an open-source backup/restore system for SQLite.
The Design & Implementation of Sprites
7mExplains the design and implementation of Sprites, a new Docker-like technology for running containers without traditional Docker.
Code And Let Live
5mArgues that ephemeral sandboxes for agent isolation are obsolete and introduces a new persistent sandbox approach.
Litestream VFS
4mDetails the Litestream VFS feature for SQLite backup and restore, using a sandwich ratings database as an example.
You Should Write An Agent
3mEncourages readers to build their own AI agents by comparing the learning process to riding a bicycle.
Corrosion
6mDescribes the challenges of gluing servers and network together in Fly.io's platform that transforms Docker containers into micro-VMs.
Kurt Got Got
4mRecounts a security incident where Fly.io's Twitter account was compromised and explains how it happened.
Litestream v0.5.0 is Here
3mAnnounces the release of Litestream v0.5.0, an open-source backup/restore system for SQLite-based applications.
Build Better Agents With MorphLLM
5mIntroduces MorphLLM for building better AI agents, drawing an analogy with audiophile equipment.
Trust Calibration for AI Software Builders
4mDiscusses trust calibration for AI software, aligning user trust with actual product capabilities.
Games as Model Eval: 1-Click Deploy AI Town on Fly.io
5mProposes using games as a method for evaluating AI models, with a one-click deploy for AI Town on Fly.io.
The Future Isn't Model Agnostic
4mArgues that AI projects should focus on a single model rather than being model agnostic for better results.
Phoenix.new – The Remote AI Runtime for Phoenix
6mPresents a new remote AI runtime for Phoenix framework, enabling LLM agents to work with Elixir.
What are MCP Servers?
4mExplains what MCP Servers are and how they integrate with AI clients like Claude and VSCode on Fly.io.
My AI Skeptic Friends Are All Nuts
5mA provocative opinion piece defending AI-assisted programming against skeptical friends who compare it to NFT mania.
Using Kamal 2.0 in Production
6mShares practical experience using Kamal 2.0 in production for deploying Rails 8 applications.
parking_lot: ffffffffffffffff...
7mDescribes a gnarly bug in Fly.io's Anycast router, the largest Rust project in their codebase.
Litestream: Revamped
5mAnnounces a major revamp of Litestream, an open-source tool for reliable SQLite recovery from object storage.
Launching MCP Servers on Fly.io
4mLaunches MCP Servers on Fly.io, discussing the six-month-old protocol's rapid adoption and evolving identity.
Provisioning Machines using MCPs
4mIntroduces using MCPs (Model Context Protocols) to provision cloud resources like Fly volumes via LLM tools.
30 Minutes With MCP and flyctl
3mDescribes building a basic MCP server for flyctl in 30 minutes to enable LLM-driven infrastructure management.
Our Best Customers Are Now Robots
5mDiscusses how automated agents and robots are increasingly becoming the primary users of Fly.io's cloud platform.
Operationalizing Macaroons
8mProvides a deep technical dive into how Fly.io implements and operationalizes Macaroon security tokens for authentication.
Taming A Voracious Rust Proxy
7mDetails a bug and performance optimization journey involving a Rust proxy in Fly.io's global networking stack.
We Were Wrong About GPUs
6mReevaluates Fly.io's earlier assumptions about GPU demand and shares progress on GPU-enabling their cloud platform.
The Exit Interview: JP Phillips
5mAn exit interview with engineer JP Phillips reflecting on his four years building Fly.io's orchestration system.
Did Semgrep Just Get A Lot More Interesting?
4mExplores how Semgrep's capabilities become more interesting when combined with LLM-driven development agents.
A Blog, If You Can Keep It
3mAnnounces a shift in Fly.io's blogging strategy toward more varied and less formal content.
VSCode’s SSH Agent Is Bananas
5mCritiques VSCode's SSH agent implementation and explores integrating Fly.io with remote editing workflows.
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