Fly.io vs Sentry
Run your app close to users, globally
vs. Application monitoring, error tracking, tracing, session replay
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
Sentry
Developer (Free)
Single user. 5k errors + 5M spans + 5GB logs + 50 replays + 1GB attachments per month.
Free
Self-Hosted (OSS)
BSL-licensed. Docker-based deploy. Free for personal/internal, commercial requires license.
$0 base (usage-based)
Team
$26/mo annual ($29/mo). Unlimited users. 50k errors/mo. 20 custom dashboards. Third-party integrations.
$26/mo
Business
$80/mo annual. 90-day insights lookback, unlimited dashboards, anomaly-detection alerts, SAML + SCIM.
$80/mo
Enterprise
Custom. Dedicated TAM, premium support, single-tenant option.
Custom
Free-tier quotas head-to-head
Comparing pay-as-you-go on Fly.io vs self-hosted on Sentry.
| Metric | Fly.io | Sentry |
|---|---|---|
| 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.
Sentry · 16 features
- Alerts — Metric + issue-based alerts routed to Slack/PagerDuty/email/etc.
- Cron Monitoring — Check-in pings for scheduled jobs. Alert on missed/failed runs.
- Distributed Tracing — Performance monitoring spans across services. Connect frontend → backend → DB.
- Error Tracking — Capture exceptions with stack traces, breadcrumbs, tags, release info, user cont…
- Insights — Pre-built dashboards per domain: Frontend, Backend, Mobile, AI, Database, LLM, e…
- LLM Monitoring — Track OpenAI/Anthropic/etc calls, token usage, cost, errors.
- Logs — Centralized structured logging correlated with errors + traces.
- Profiling — CPU profiling for Python, Node.js, Go, PHP, Ruby, Android, iOS.
- Release Health — Adoption + crash-free rate per release version.
- Releases — Track deploys, commit hooks, source map upload, bisect.
- Seer (AI Debug) — Root cause analysis + fix suggestions for issues via AI.
- Self-Hosting — Docker-based self-host. Feature parity.
- Session Replay — Record DOM + network to replay user sessions that hit errors.
- Source Maps — Auto-symbolicate minified code. Upload via CLI or Webpack/Vite plugin.
- Uptime Monitoring — Synthetic checks for HTTP endpoints.
- User Feedback — In-app feedback widget tied to sessions.
Developer interfaces
| Kind | Fly.io | Sentry |
|---|---|---|
| CLI | flyctl CLI | Sentry CLI |
| SDK | — | sentry-android, @sentry/browser, sentry-cocoa (iOS), sentry-dotnet, sentry_flutter, sentry-go, sentry-java, @sentry/node, sentry-php, @sentry/react-native, sentry-ruby, sentry-sdk (Python), sentry-unity |
| REST | Machines API | Sentry REST API |
| GRAPHQL | Fly GraphQL API | — |
| MCP | — | Sentry MCP |
| OTHER | Fly Postgres (wire) | Webhooks (Alerts) |
Staxly is an independent catalog of developer platforms. Outbound links to Fly.io and Sentry are plain references to their official websites. Pricing is verified against vendor pages at publication time — reconfirm before buying.
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