Values are comparable only within the scope shown. Runtime, plan, model, invocation mode, and account-specific capacity can change the effective result.
Quick comparison
| Criterion | Railway | Fly.io | Comparability note |
|---|---|---|---|
| Default/plan volume capacity | RailwayFree/Trial: 0.5 GB; Hobby: 5 GB; Pro: 50 GBPlan dependentRailway | Fly.io1 GB default; 500 GB maximumPer volumeFly.io | Railway's value lists plan allocations; Fly's value lists per-volume default and maximum. |
| Expansion path | RailwayPro self-serve up to 1 TBProRailway | Fly.io1 GB default; 500 GB maximumPer volumeFly.io | Neither value means storage is shared automatically across replicas. |
Which is best for your requirement?
Choose Railway when
Its documented default/plan volume capacity scope fits your measured workload and the caveats shown in the comparison.
Choose Fly.io when
Its documented execution or account model better matches the exact requirement rather than a vendor-wide headline.
Validate before migration
Test payload, duration, throughput, concurrency, failure behavior, billing scope, and recovery with representative traffic.
Validate the decision with your workload
Before choosing between Railway and Fly.io, reproduce the comparison with the exact plans, models, regions, runtimes, and invocation paths you intend to operate. The reviewed rows cover default/plan volume capacity and expansion path; they do not turn different pricing, reliability, developer experience, or ecosystem tradeoffs into one universal score.
- Capture representative request sizes, token usage, duration, concurrency, storage, and failure behavior at realistic percentiles.
- Test the boundary and the recovery path on both candidates, including throttling, timeouts, partial failure, retries, and cost controls.
- Record which scoped observation drove the choice and recheck its official source before migration or a major traffic increase.
Official sources
Related