Fly Machines
ELI5 — The Vibe Check
Fly Machines are micro-VMs that start in about 300ms and run anywhere on Fly.io's global network. They're like containers but with hardware-level isolation, and they can scale to zero when idle. Need a VM in Tokyo, London, and São Paulo? Done. It's the 'goldilocks' between serverless functions and full servers.
Real Talk
Fly Machines are fast-launching, hardware-isolated micro-VMs on Fly.io's global network. They boot in ~300ms, support scale-to-zero, and can run any Docker container in 30+ regions. They provide a REST API for programmatic control, enabling patterns like per-user VMs, on-demand compute, and auto-scaling based on demand.
When You'll Hear This
"We run a Fly Machine per customer for perfect isolation." / "Fly Machines scale to zero between requests — we only pay when there's traffic."
Related Terms
Container
A container is a running instance of a Docker image — it's the lunchbox you made and actually opened to eat from.
Edge Computing
Your server is in Virginia. Your user is in Tokyo. Every request travels 10,000 km and back.
Fly.io
Fly.io is a cool newer platform that takes your Docker container and runs it close to your users anywhere in the world.
Serverless
Serverless doesn't mean there are no servers — it means YOU don't have to think about servers. Someone else manages them, scales them, and patches them.