Firebase vs Fly.io
Google's mobile & web app development platform
vs. Run your app close to users, globally
Pricing tiers
Firebase
Spark (No-cost)
Free tier with generous quotas. No credit card required. Cannot exceed free quotas.
Free
Blaze (Pay as you go)
Usage-based billing. Includes Spark quotas free, then pay Google Cloud rates. Required for Cloud Functions outbound networking, scheduled jobs, some extensions.
Custom
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
Free-tier quotas head-to-head
Comparing spark on Firebase vs pay-as-you-go on Fly.io.
| Metric | Firebase | Fly.io |
|---|---|---|
| auth mau | 50000 users/month | — |
| firestore deletes per day | 20000 docs/day | — |
| firestore egress gib month | 10 GiB/month | — |
| firestore reads per day | 50000 docs/day | — |
| firestore storage gib | 1 GiB | — |
| firestore writes per day | 20000 docs/day | — |
| functions cpu seconds | 200000 CPU-sec/month | — |
| functions gb seconds | 400000 GB-sec/month | — |
| functions invocations | 2000000 invocations/mo | — |
| functions outbound gb | 5 GB/month | — |
| hosting storage gb | 10 GB | — |
| hosting transfer gb month | 10.8 GB/month | — |
| phone sms verifications day | 10 sms/day | — |
| rtdb connections | 100 connections | — |
| rtdb downloaded gb month | 10 GB/month | — |
| rtdb stored gb | 1 GB | — |
| storage downloaded gb day | 1 GB/day | — |
| storage gb | 5 GB | — |
| storage operations day | 50000 ops/day | — |
Features
Firebase · 20 features
- A/B Testing — Experiments on Remote Config params, FCM notifications, and Analytics events. Ba…
- App Check — Attestation service: only requests from authentic, untampered app instances reac…
- App Hosting — Managed hosting for modern web apps (Next.js, Angular, SvelteKit). Git-based dep…
- Cloud Firestore — Serverless NoSQL document database. Real-time sync, ACID transactions, offline p…
- Cloud Functions — Serverless functions (Node.js/Python). Trigger on HTTP, Firestore, RTDB, Auth, S…
- Cloud Storage — Object storage for user files. Built on GCS. Security rules + signed URLs. Resum…
- Crashlytics — Real-time crash reporting for iOS/Android/Unity/Flutter. Stack traces, breadcrum…
- Data Connect — GraphQL API backed by Cloud SQL for PostgreSQL. Type-safe SDK generation. Previe…
- Dynamic Links — Deep links that survive app install. NOTE: deprecated, shutdown Aug 2025 — migra…
- FCM Topics — Publish/subscribe messaging: devices subscribe to topic names; backend sends one…
- Firebase AI Logic — Client-side SDK to call Gemini models directly from mobile/web. Formerly "Vertex…
- Firebase Authentication — Drop-in auth: email/password, phone, anonymous, 10+ federated providers, custom …
- Firebase Cloud Messaging — Push notifications for iOS, Android, Web (APNs/FCM transports). Topics, device g…
- Firebase Extensions — Pre-packaged Cloud Functions + config: Stripe, Algolia search, image resize, tra…
- Firebase Hosting — Static + dynamic hosting with global CDN. Preview channels, atomic deploys, rewr…
- Genkit — Open-source AI app framework. Unified API for Gemini, OpenAI, Ollama; tools, RAG…
- Google Analytics for Firebase — Free unlimited event tracking with audience building. BigQuery export on Blaze. …
- Performance Monitoring — App startup, HTTP network, and custom traces. Integrates with Google Analytics e…
- Realtime Database — Low-latency JSON tree database with WebSocket sync. Best for high-frequency pres…
- Remote Config — Feature flags / parameterized config with conditional targeting (user property, …
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.
Developer interfaces
| Kind | Firebase | Fly.io |
|---|---|---|
| CLI | Firebase CLI | flyctl CLI |
| SDK | Admin SDK (Go), Admin SDK (Java), Admin SDK (Node.js), Admin SDK (Python), Android SDK, Apple Platforms SDK, Flutter SDK (FlutterFire), JavaScript SDK, Unity SDK | — |
| REST | Auth REST API, Cloud Storage REST, Firebase Management API, Firestore REST API, Realtime Database REST | Machines API |
| GRAPHQL | — | Fly GraphQL API |
| MCP | Firebase MCP Server | — |
| OTHER | Firestore gRPC, Realtime Database WebSocket | Fly Postgres (wire) |
Staxly is an independent catalog of developer platforms. Outbound links to Firebase and Fly.io are plain references to their official websites. Pricing is verified against vendor pages at publication time — reconfirm before buying.
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