Fly Machines
Fly Machines are virtual machines managed through a REST API or flyctl. They run application code packaged as Docker/OCI images inside Firecracker microVMs, with control over lifecycle, resources, and region placement. They are used by applications and automation systems that need isolated compute.
| Pricing model | Per-second billing on running CPU/RAM preset; stopped machines billed for rootfs storage |
|---|---|
| Pricing The headline compute price as the provider states it. Sorting ranks prices stated per vCPU over time, converted to hourly. Other pricing models sort after, unranked. | From $0.0027/hr (shared-cpu-1x, 256 MB) with per-second metering |
| Free while idle Whether a stopped, paused, or sleeping sandbox costs nothing. | ✕ |
| Elastic Resources flex with what the sandbox actually uses, and the bill follows: yes when the provider bills on active or observed use, no when capacity is reserved or allocated and billed while it runs. | ✕ |
| Memory snapshots Whether RAM state survives a pause and resume, not just disk. | ✓ |
| Wake on request Whether a stopped sandbox wakes automatically on inbound traffic. | ✓ |
| Start / resume Typical time from create or resume to running. Sorting ranks stated times, converted to seconds; claims with no figure sort after, unranked. | Well under 1 s to start a stopped Machine; a few hundred ms from suspend; ~2+ s cold start for common apps; low double-digit seconds to create a new Machine |
| Max runtime The longest a sandbox may run. | No fixed limit |
| Isolation The isolation technology between sandboxes. | Firecracker microVM |
| GPUs Whether GPU instances are available for sandboxes. | ✕ |
| Docker Whether Docker containers can run inside the sandbox. | ✕ |
| SDKs | Go, Python, Ruby |
✓ yes · ✕ no · – no cited public fact.
Suspend snapshots preserve RAM and resume in a few hundred ms, but they are not guaranteed to persist; deployments, host migration, corruption, and system maintenance can force a cold start. Suspended and stopped Machines still incur rootfs storage charges at $0.15 per GB per month, and suspended Machines continue to reserve regional capacity.
Sources
- https://fly.io/docs/machines/flyctl/fly-machine-run/
- https://fly.io/docs/languages-and-frameworks/dockerfile/
- https://community.fly.io/t/feature-request-better-api-docs-or-an-official-fly-sdk/14894
- https://github.com/sosedoff/fly-machines
- https://community.fly.io/t/machines-take-3-8s-to-start-when-hitting-them-during-shutdown/7022
- https://dev.to/aerc18/why-my-lightning-fast-spring-boot-native-app-took-9-seconds-to-boot-on-flyio-db5
- https://fly.io/blog/fly-machines/
- https://fly.io/docs/about/pricing/
- https://fly.io/docs/machines/overview/
- https://fly.io/docs/reference/suspend-resume/
- https://community.fly.io/t/new-feature-in-preview-suspend-resume-for-machines/20672
- https://fly.io/docs/machines/
- https://docs.machines.dev/
- https://community.fly.io/t/fly-machines-create-and-forget-and-limitations/11244
- https://github.com/superfly/fly-openapi-sdk
- https://raw.githubusercontent.com/superfly/fly-go/main/README.md
- https://github.com/superfly/fly-go
- https://fly.io/docs/gpus/
- https://fly.io/docs/gpus/getting-started-gpus/
- https://community.fly.io/t/gpu-migration-fly-io-gpus-will-be-deprecated-as-of-july-31-2026/27110
- https://fly.io/docs/launch/autostop-autostart/
- https://fly.io/docs/about/billing/
- https://fly.io/pricing/
- https://fly.io/docs/blueprints/working-with-docker/
- https://fly.io/blog/docker-without-docker/
- https://fly.io/docs/reference/architecture/
- https://fly.io/blog/wrong-about-gpu/
Last verified 2026-10-02. Corrections land through the update log.