Fly.io vs Kinde
Run your app close to users, globally
vs. Flexible authentication, user management, and feature flags
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
Kinde
Free
10,500 MAU included. MFA, B2B orgs, custom domain, 2 custom roles, 1 webhook, 2 environments.
Free
Pro
Unlimited webhooks, roles, feature flags, API keys. Remove Kinde branding. SOC 2 attestation.
$25/mo
Plus
Unlimited enterprise SSO, API scopes, org-owned M2M apps, 6 environments.
$75/mo
Scale
11 environments, custom domain per org, SCIM, MFA triggers, 30-day audit logs.
$250/mo
Enterprise
Custom. Dedicated infra option, volume discounts, custom SLAs.
Custom
Free-tier quotas head-to-head
Comparing pay-as-you-go on Fly.io vs free on Kinde.
| Metric | Fly.io | Kinde |
|---|---|---|
| custom roles | — | 2 roles |
| environments | — | 2 envs |
| feature flags | — | 10 flags |
| mau included | — | 10500 users/month |
| webhooks | — | 1 webhooks |
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.
Kinde · 14 features
- API Scopes — OAuth scopes for your APIs, enforced server-side (Plus+).
- B2B Organizations — Multi-tenant orgs with user roles, invitations, feature flags per org.
- Custom Domain — Host auth at auth.yourbrand.com. Free tier includes this.
- Enterprise SSO — SAML 2.0 + OIDC enterprise connections (Plus unlimited).
- Feature Flags — Built-in feature flags with per-user/org overrides. No separate service needed.
- Kinde AI — AI-assisted query and insights over your Kinde data.
- Kinde Billing (preview) — Built-in subscription billing linked to users/orgs. Stripe under the hood.
- Machine-to-Machine — Client credentials grant for service-to-service auth.
- Multi-Factor Auth — TOTP authenticator apps, SMS, email, passkey.
- Passwordless — Email code + passkey (WebAuthn).
- Roles & Permissions — RBAC with roles → permissions. Assigned per user or per organization.
- SCIM Provisioning — Directory provisioning from IdPs (Scale tier).
- Sign-in Widget — Hosted pages + themeable widget for login/signup. Customizable with CSS.
- Webhooks — Event webhooks: user.created/updated, organization events, MFA, etc.
Developer interfaces
| Kind | Fly.io | Kinde |
|---|---|---|
| CLI | flyctl CLI | — |
| SDK | — | Kinde Android / Kotlin, Kinde Flutter SDK, Kinde Go SDK, Kinde iOS / Swift, @kinde-oss/kinde-auth-nextjs, @kinde-oss/kinde-auth-react, @kinde-oss/kinde-nodejs-sdk, Kinde Python SDK |
| REST | Machines API | Kinde Management API |
| GRAPHQL | Fly GraphQL API | — |
| MCP | — | Kinde MCP |
| OTHER | Fly Postgres (wire) | — |
Staxly is an independent catalog of developer platforms. Outbound links to Fly.io and Kinde are plain references to their official websites. Pricing is verified against vendor pages at publication time — reconfirm before buying.
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