E2B vs Fly.io Machines
| E2B | Fly.io Machines | |
|---|---|---|
| Isolation | Firecracker microVM | microVM |
| Cold start | 150ms | 300ms |
| Price / vCPU-hr | $0.05 | $0.07 |
| GPU | No | GPUs available |
| Session limit | Up to 24h | Persistent |
| Persistence | Pause/resume with memory state, snapshots | Persistent ext4 filesystem, checkpoints |
| MCP support | n/a | Yes |
| Free tier | $100 one-time credit (Hobby) | Pay-as-you-go |
| Best for | Teams that want the cleanest SDK and strong microVM isolation for agent code execution. | Teams wanting a low-level, MCP-native VM primitive with zero idle cost. |
The verdict
Choose E2B for teams that want the cleanest SDK and strong microVM isolation for agent code execution. Choose Fly.io Machines for teams wanting a low-level, MCP-native VM primitive with zero idle cost.
Headline rates rarely equal your bill. Idle time, session length, creation fees and GPU minutes dominate. Model your actual workload in the cost calculator.
FAQ
E2B vs Fly.io Machines: which is better?
It depends on your priority. E2B leads on both cold start (150ms vs 300ms) and the headline vCPU-hour price. E2B is best for teams that want the cleanest SDK and strong microVM isolation for agent code execution. Fly.io Machines is best for teams wanting a low-level, MCP-native VM primitive with zero idle cost.
Is E2B or Fly.io Machines cheaper?
E2B is cheaper on the headline vCPU-hour rate ($0.05 vs $0.07). Total cost depends on idle time, session length and creation fees. Model your workload in the cost calculator.
Still choosing between E2B and Fly.io Machines?
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