Fly.io vs GrowthBook
Run your app close to users, globally
vs. Open-source feature flags + experimentation — Warehouse Native
Pricing tiers
Fly.io
Pay-as-you-go
No monthly fee. Machines billed per second. Free allocations: ~3 small shared machines + 3 GB volumes.
$0 base (usage-based)
Shared CPU 1x — 256 MB
Entry VM. 1 shared vCPU, 256 MB RAM. ~$2.02/month continuously on.
$2/mo
Performance 1x — 2 GB
Dedicated 1 vCPU, 2 GB RAM.
$32/mo
Reservation — Shared (1 yr)
$36/year for $5/mo credit (40% savings).
$36/mo
Shared CPU 8x — 16 GB
8 shared vCPU, 16 GB RAM.
$89/mo
Performance 16x — 128 GB
Dedicated 16 vCPU, 128 GB RAM.
$1014/mo
Enterprise
Custom. Dedicated capacity, SLA.
Custom
GrowthBook
Open Source (Self-Host)
MIT-licensed. Unlimited everything. Community support.
$0 base (usage-based)
Cloud — Starter (Free)
Up to 3 users. Unlimited flags + experiments. Warehouse Native included.
Free
Cloud — Pro
$40/user/month. Up to 50 users. Advanced stats, visual A/B editor, CUPED, sequential testing, bandits.
$40/mo
Cloud — Enterprise
Custom. Unlimited users, SSO/SAML, approval flows, data pipelines, exportable audit logs.
Custom
Self-Host Enterprise
Open Source + Enterprise license. Visual A/B editor, advanced metrics, SSO/SAML, approvals, training.
Custom
Free-tier quotas head-to-head
Comparing pay-as-you-go on Fly.io vs oss on GrowthBook.
| Metric | Fly.io | GrowthBook |
|---|---|---|
| No overlapping quota metrics for these tiers. | ||
Features
Fly.io · 14 features
- Auto Stop/Start — Machines auto-stop when idle, start on request (like scale-to-zero).
- Certs — Let's Encrypt + wildcard certs managed.
- Fly GPU — A100/L40S/A10 on-demand GPU machines.
- Fly Kubernetes (FKS) — Managed Kubernetes on Fly machines.
- Fly Machines — Firecracker microVMs. Start in <1s. Run any Docker image.
- Fly Postgres — Managed Postgres via Supabase partnership (2024). Also legacy self-run Postgres …
- fly-replay headers — Route request to another region at app level.
- Fly Volumes — Persistent SSD attached to a Machine. Encrypted at rest.
- Global Anycast — Single IP routes to the closest region automatically.
- LiteFS — Distributed SQLite with primary/replica across regions.
- Private Networks — 6PN WireGuard mesh. Connect machines across regions privately.
- Secrets — Encrypted env vars propagated to all regions.
- Tigris (partner) — S3-compatible storage for Fly apps. By partner.
- Upstash Redis (partner) — Managed Redis via Upstash.
GrowthBook · 15 features
- Approval Flows — Require reviewer approval on flag changes. Enterprise.
- Audit Logs — Full change history. Exportable on Enterprise.
- Dimensions & Slicing — Break down experiment results by user dimensions.
- Edge SDK Support — Cloudflare Workers, Lambda@Edge, Fastly, Akamai EdgeWorkers, Netlify Edge.
- Experiments — A/B/n with CUPED variance reduction + sequential testing.
- Feature Flags — Boolean + string + number + JSON flags with targeting.
- Feature Reviews (PR-style) — Draft → review → approve flag changes.
- Guardrail Metrics — Auto-monitor key metrics during experiments.
- Metric Catalog — Define + reuse metrics across experiments.
- Multi-Armed Bandits — Adaptive traffic allocation. Pro+.
- Safe Rollouts — Guarded gradual rollouts with automatic rollback.
- SSO / SAML — Enterprise SSO for cloud + self-host EE.
- Sticky Bucketing — User stays in variant even after eligibility changes.
- Visual A/B Test Editor — No-code DOM editor for web experiments. Pro+.
- Warehouse Native — Connect your warehouse + run experiments against your events data.
Developer interfaces
| Kind | Fly.io | GrowthBook |
|---|---|---|
| CLI | flyctl CLI | — |
| SDK | — | Edge SDKs (CF Workers / Lambda@Edge / Fastly / Akamai), growthbook-android, growthbook-flutter, growthbook-go, growthbook-java, growthbook-node, growthbook-php, growthbook-python, growthbook-ruby, growthbook-swift, sdk-javascript, sdk-react |
| REST | Machines API | GrowthBook REST API |
| GRAPHQL | Fly GraphQL API | — |
| OTHER | Fly Postgres (wire) | Webhooks |
Staxly is an independent catalog of developer platforms. Outbound links to Fly.io and GrowthBook are plain references to their official websites. Pricing is verified against vendor pages at publication time — reconfirm before buying.
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