Convex vs Fly.io
The reactive database where queries are TypeScript code
vs. Run your app close to users, globally
Pricing tiers
Convex
Starter (Free)
Free with overage via usage-based billing. Great for prototypes.
Free
Professional
$25/developer/month. Overage: $2/M function calls. Daily backups, email support, custom domains.
$25/mo
Business / Enterprise
From $2,500/month. SAML/SSO, SLA, dedicated deployments, Slack Connect support.
$2500/mo
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 starter on Convex vs pay-as-you-go on Fly.io.
| Metric | Convex | Fly.io |
|---|---|---|
| db storage gb | 0.5 GB | — |
| deployments | 40 deployments | — |
| egress gb month | 1 GB/month | — |
| file storage gb | 1 GB | — |
| function calls month | 1000000 calls/month | — |
| team members | 6 users | — |
Features
Convex · 18 features
- Actions — Non-deterministic functions for external I/O (fetch, AI APIs, email). Cannot rea…
- Authentication — Convex Auth (built-in) or BYO provider (Clerk, Auth0, Kinde, WorkOS). ID tokens …
- Convex Agents — AI agent framework with durable memory, threads, tool use. Works with OpenAI / A…
- Convex Auth — First-party auth library: passwords, magic links, OAuth, phone — stored in your …
- Convex Components — Reusable backend modules (rate limiter, workflow, aggregate, action-retrier, etc…
- Cron Jobs — Recurring schedules defined in convex/crons.ts. UTC, cron-style patterns.
- Durable Workflows — Long-running multi-step workflows with retries and at-least-once guarantees.
- Exception Reporting — Auto-capture errors to Sentry, Axiom, Datadog.
- File Storage — Upload/download via storage API. Returns storage IDs referenced in documents.
- Full-Text Search — BM25 search index on table fields. withSearchIndex query helper.
- HTTP Actions — Expose public HTTP endpoints for webhooks, OAuth callbacks, third-party integrat…
- Log Streams — Stream function logs to Axiom, Datadog, Sentry. Pro+.
- Mutations — Transactional write functions. All reads + writes in one mutation are ACID; conf…
- Preview Deployments — Every Git branch gets its own isolated deployment. Integrates with Vercel/Netlif…
- Queries — Deterministic read-only TS functions. Automatically cached and re-run when under…
- Real-Time Subscriptions — useQuery auto-subscribes; server invalidates when data a query read changes. No …
- Scheduler — schedule.after / schedule.at — enqueue functions to run later. Durable, survives…
- Vector Search — Native vector index on tables. withIndex + filter fields. Up to 4096 dims.
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 | Convex | Fly.io |
|---|---|---|
| CLI | Convex CLI | flyctl CLI |
| SDK | Android / Kotlin Client, iOS / Swift Client, JavaScript/TypeScript Client, Next.js Integration, Python Client, React Client (useQuery), Rust Client, Svelte Client, Vue Client | — |
| REST | Deploy / Dashboard API, HTTP Actions | Machines API |
| GRAPHQL | — | Fly GraphQL API |
| OTHER | WebSocket Subscriptions | Fly Postgres (wire) |
Staxly is an independent catalog of developer platforms. Outbound links to Convex 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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