Head to head
Modal vs Fly.io Machines
A side-by-side, sourced comparison. Facts come from each vendor’s own materials; scores are our editorial opinion applied by the same rubric to both.
| Dimension | ||
|---|---|---|
| Pricing | Starter is $0 base + $30/mo of free compute credits; Team is $250/mo base + $100/mo credits; Enterprise is custom. Usage is per-second (e.g. H100 GPU at $0.001097/s, CPU at $0.0000131/core/s).source ↗ | Usage-based, billed per second while running (e.g. shared-cpu-1x/256MB roughly $2/mo; performance-1x/2GB roughly $32/mo). Volumes are $0.15/GB-month and egress varies by region. No standing free tier is advertised.source ↗ |
| Hosting model | Fully managed, multi-cloud serverless with a proprietary container runtime and scheduler that autoscales from zero to 1000+ GPUs.source ↗ | Hardware-virtualized micro-VMs on Fly-operated servers across 18 documented regions on six continents.source ↗ |
| Memory & state | Durable primitives — Volumes (a distributed file system persisted across invocations), plus Dicts and Queues. This is infrastructure state, not agent memory.source ↗ | Durable state via Fly Volumes (persistent block storage) and snapshots; Machines can be persistent or stopped (stopped root filesystem is retained). Machine RAM itself is ephemeral.source ↗ |
| MCP support | Partialsource ↗ | Nativesource ↗ |
| Integrations | A Python-native SDK and CLI as the primary interface, plus Sandboxes, Notebooks, web-endpoint deployment, and observability.source ↗ | A Machines REST API and flyctl CLI, Fly Launch for containerized deploys, and a native fly mcp command surface with client wiring for major editors.source ↗ |
| Model providers | Not applicable — pure compute; you bring and run your own models.source ↗ | Not applicable — pure compute/hosting; commonly used to host MCP servers and AI workloads.source ↗ |
| Open source | Nosource ↗ | NoUnverified |
| Developer experience(opinion) | 5/5 | 4/5 |
| Pricing transparency & value(opinion) | 4/5 | 3/5 |
| Scalability(opinion) | 5/5 | 5/5 |
| Memory & state(opinion) | 3/5 | 3/5 |
| Integrations(opinion) | 2/5 | 3/5 |
| MCP nativeness(opinion) | 2/5 | 4/5 |
The balanced view
Editorial opinion, derived from the scorecard above
Where Modal scores higher
In our rubric, Modal rates ahead on developer experience, pricing transparency & value.
Where Fly.io Machines scores higher
In our rubric, Fly.io Machines rates ahead on integrations, mcp nativeness.
These two serve different needs — read the full dossiers for Modal and Fly.io Machines before deciding. Neither has been hands-on tested by us yet.
Product and company names are trademarks of their respective owners and are used here only to identify the products under discussion.