Fly.io Review 2026: The Cloud Platform Built for Docker Deployments

For developers who want to deploy Docker apps without managing servers, Fly.io has become one of the most compelling options in the cloud market. With VMs that boot in under a second, automatic edge deployment across 18+ global regions, per-second billing, and a generous free tier, this platform has earned a strong following among developers — from indie hackers to mid-sized engineering teams.

In 2026, Fly.io also introduced Sprites — persistent Linux computers purpose-built for AI agents — making this Platform one of the top choices for teams building agentic AI infrastructure as well.

In this review, we cover everything you need to know: how Fly.io pricing actually works, what makes Fly Machines different from traditional VPS, who should use Sprites, and an honest comparison with DigitalOcean and Hetzner.

What is Fly.io? Overview and Key Differentiators

Fly.io is a US-based public cloud platform founded in 2017 by Kurt Mackey and Thomas Ptacek. Its core idea: make deploying containerized applications as simple as possible, while running on hardware-isolated Linux VMs (using Firecracker microVMs) rather than shared-namespace containers as older PaaS platforms did. You get the security of a real VM with the fast startup characteristics of a container.

What sets Fly.io apart from a traditional VPS provider:

• Edge Deployment: Deploy your app to 18+ regions simultaneously; traffic is routed to the closest region automatically via Anycast.
• Sub-second VM boot: Stopped Machines restart in under 1 second — fast enough to wake up in response to a live HTTP request (scale-from-zero).
• Per-second billing: Pay only for the seconds your VM actually runs. Scale-to-zero means idle apps cost $0.
• Generous free tier: 3 VMs + 3 GB storage + 160 GB outbound bandwidth per month, free.
• 99.9% uptime SLA with typical deploy times around 500 ms.

Fly.io's Three Core Products

1. Fly Machines — The Compute Backbone

Fly Machines are fast-booting VMs that power everything on Fly.io. Every app deployed with flyctl launch runs on Fly Machines. Each Machine is a fully isolated Linux VM (via Firecracker) that can boot from stopped state in under a second — fast enough to wake on an incoming request.

Machines are controllable through a full REST API, giving developers fine-grained control over VM lifecycle, placement, and resources without being locked into higher-level abstractions.

2. Sprites — Linux Computers for AI Agents (2026)

Sprites are hardware-isolated Linux computers designed specifically for AI agents. Unlike Fly Machines, a Sprite maintains persistent state: the entire filesystem and running services are checkpointed automatically. When an agent goes idle, the Sprite sleeps — billing drops to zero — and wakes up with everything exactly where it was left.

Sprites also feature a growing filesystem (up to 100 GB, billed per byte used) and Sprites Connectors that let agents securely reach external services like OpenRouter, GitHub, or Slack without ever storing tokens in the VM itself.

3. Managed Postgres — Production PostgreSQL, Simplified

Managed Postgres on Fly.io delivers production-ready PostgreSQL with automatic backups, failover, and PgBouncer connection pooling. It deploys in the same region as your app, minimising latency. You can also add read replicas in other regions for read-heavy workloads.

Fly.io Pricing: How Per-Second Billing Works

Fly.io uses pay-as-you-go per-second billing. There is no monthly subscription — you pay for the seconds your VM is actually running. If your app scales to zero, you pay $0. If it runs 24/7, you pay the full monthly equivalent.

Free Tier (Hobby Plan)

• 3 × shared-cpu-1x 256 MB VMs — free, always
• 3 GB Persistent Volume storage — free
• 160 GB outbound transfer per month — free

Fly Machines Pricing (Approximate Monthly Cost, 24/7 Runtime)

Prices below are calculated from Fly.io's published per-second rates. Shared CPU costs $0.0000008465/vCPU/sec; performance (dedicated) CPU costs $0.000012732/vCPU/sec; RAM costs $0.000002316/GB/sec (beyond the included RAM per vCPU).

Data as of October 2026. Prices are approximations based on Fly.io's published per-second rates. Singapore markup is ×1.2692 over US East. Always verify current pricing at fly.io/docs/about/pricing.

Regional Price Multipliers

Fly.io applies regional markup to its base (US East) pricing:

• US East (Ashburn VA, Secaucus NJ): base price (×1.00)
• Amsterdam, Stockholm: ×1.038
• Frankfurt, London, Paris: ×1.135–1.154
• Singapore, Sydney: ×1.269
• Tokyo: ×1.308
• São Paulo: ×1.615 (highest)

Storage and Bandwidth

Persistent Volume storage beyond the free 3 GB: $0.15/GB/month.
Outbound bandwidth beyond the free 160 GB: rates vary by region — check fly.io for current egress pricing.

Fly Machines: VMs That Boot in Under a Second

The headline feature of Fly Machines is their extraordinarily fast boot time from stopped state. When a Machine is stopped (assembled and ready but not running), restarting it takes well under a second. That's fast enough to start a VM in direct response to an incoming HTTP request — true scale-from-zero without painful cold-start latency.

The Fly Machine Lifecycle

1. Created: The Machine is created — Fly.io reserves capacity, fetches your Docker image, and builds the root filesystem. This can take low double-digit seconds the first time.
2. Started: The VM boots. Because the components are already assembled, boot takes under 1 second.
3. Stopped: The VM shuts down, but remains assembled on Fly.io's worker host — ready to start again instantly. No billing in stopped state.
4. Destroyed: The Machine is permanently deleted; all resources are freed.

Patterns Enabled by Fast Boot

• Scale-from-zero: Idle apps pay nothing; they wake up on the first request within the same second.
• On-demand compute: Spin up a VM per job (video transcoding, AI inference), destroy it when done.
• Ephemeral review environments: Create a fresh environment for every PR, tear it down on merge.
• Zero-downtime blue-green deploys: Bring new Machines live before stopping old ones.

Machines REST API

Every aspect of a Fly Machine's lifecycle is controllable through a REST API. This allows developers to build their own orchestration on top of Fly.io — dynamic VM provisioning, custom CI pipelines, or per-request compute pools — without depending on flyctl.

Sprites: Persistent Linux Computers for AI Agents

Fly.io's most notable 2026 addition is Sprites — hardware-isolated Linux computers designed from the ground up for AI agents. The key insight is that AI agents need persistent state: they return to the same environment they left, with the same files, the same installed packages, the same running services.

What Makes Sprites Different

• Persistent filesystem: Everything is still there when the agent returns — no re-setup, no re-downloading dependencies.
• Automatic checkpointing: Sprites checkpoint themselves continuously. Roll back to any recent checkpoint in seconds if something goes wrong.
• Sleep when idle, pay nothing: The Sprite pauses when the agent stops working and wakes — with full state restored — when the agent resumes.
• Auto-expanding disk: Disk grows as you write to it, up to 100 GB per Sprite. You're billed only for bytes actually written.
• Sprites Connectors: Connect external services (OpenRouter, GitHub, Slack) once per organisation; every Sprite can access them without holding any credentials.

Ideal Sprites Use Cases

• Coding agents (Claude Code, Codex): each agent gets its own isolated Linux box with a durable filesystem.
• Personal agents that access your inbox and calendar — they shouldn't live on your laptop.
• MCP servers: run each MCP server in its own Sprite, with persistent disk and egress policy, billed only for usage.
• Untrusted code execution: hardware-isolated VMs prevent state leakage between users.
• Agent-built apps: every Sprite has an HTTPS URL — the app your agent built stays exactly where it was created.

Note: Sprites Block Device (the persistent filesystem feature) is in private beta as of October 2026. Check fly.io/early-access for current availability.

Managed Postgres on Fly.io

Fly.io's Managed Postgres runs in the same region as your application — critical for low-latency database access — and includes everything you need for production use.

Key Features

• Automatic backups on a regular schedule
• Automatic failover when the primary instance fails
• PgBouncer connection pooling built in — handles connection limits gracefully
• Read replicas in other regions for read-heavy, globally distributed workloads
• Private networking — your database is never directly exposed to the public internet
• Standard PostgreSQL — not a fork, so all extensions work as expected

Pricing

Managed Postgres is billed the same way as Fly Machines: per second, based on the CPU and RAM of the database instance. A minimal single-node Postgres cluster typically starts around $15–30/month depending on region and configuration. See fly.io/mpg.md for up-to-date details.

18+ Global Regions and Anycast Routing

Fly.io operates in 18+ regions (as of October 2026). Deploying in multiple regions gives your users low-latency access regardless of where they are — and Fly.io's Anycast routing sends each request to the nearest healthy instance automatically.

Regions Closest to Southeast Asia

• sin (Singapore) — closest to Thailand and SE Asia; recommended for this region (×1.269 price vs. US East)
• nrt (Tokyo, Japan) — good fallback for East Asia (×1.308)
• syd (Sydney, Australia) — ANZ/Pacific users

Full Region List

• Europe: Amsterdam (ams), Frankfurt (fra), London (lhr), Paris (cdg), Stockholm (arn)
• United States: Ashburn VA (iad), Chicago (ord), Dallas (dfw), Los Angeles (lax), San Jose (sjc), Secaucus NJ (ewr)
• Other: Toronto (yyz), São Paulo (gru), Johannesburg (jnb)

Region list as of October 2026. Fly.io adds new regions periodically — verify at fly.io.

How to Deploy an App on Fly.io: Step by Step

Most developers can get their first app deployed in under 10 minutes, especially if they already have a Dockerfile.

1. Create a Fly.io account at fly.io (free, sign up with email or GitHub)
2. Install flyctl:
   curl -L https://fly.io/install.sh | sh
   or on macOS: brew install flyctl
3. Log in: flyctl auth login (opens a browser window)
4. Launch your app from the directory containing your Dockerfile or source code:
   flyctl launch
   flyctl auto-detects your language and framework, creates fly.toml, and generates a Dockerfile if you don't have one.
5. Deploy: flyctl deploy
   Fly.io builds your Docker image, pushes it to its registry, and deploys in your chosen region. First deploys typically take 1–3 minutes; subsequent deploys run in ~500 ms.

Scaling Commands

Scale to a larger VM: flyctl scale vm performance-2x
Scale instance count: flyctl scale count 3
Add a new region: flyctl regions add sin
Enable scale-to-zero: set auto_stop_machines = true in fly.toml under [http_service]

GitHub Actions CI/CD

Fly.io publishes an official GitHub Action (superfly/flyctl-actions). Add FLY_API_TOKEN to GitHub Secrets and drop a workflow YAML in your repository — CI/CD is live in under 5 minutes.

Supported Languages and Frameworks

Fly.io supports any language or framework that runs in Docker. Official quickstart guides cover:

• JavaScript/Node.js: Express, Fastify, NestJS, Next.js, Remix, Nuxt, Astro
• Python: Django, FastAPI, Flask, Streamlit
• Ruby: Ruby on Rails, Sinatra
• Elixir: Phoenix (Fly.io is Phoenix's recommended platform)
• Go: standard library, Gin, Fiber, Echo
• Rust: Actix, Axum, Tokio
• JVM: Spring Boot, Quarkus, Micronaut
• PHP: Laravel, WordPress (via Docker)
• Static sites: Gatsby, Hugo, Jekyll (via nginx image)

Pros and Cons

Pros

• Docker-native: If you have a Dockerfile, you can deploy in minutes.
• Sub-second VM boot: Real scale-from-zero with no painful cold starts.
• Automatic edge routing: Anycast sends users to the nearest region automatically.
• Per-second billing: You only pay for actual usage; scale-to-zero saves real money.
• Excellent free tier: 3 VMs + 3 GB storage + 160 GB bandwidth/month.
• Private IPv6 mesh: All VMs in the same organisation communicate over a private network automatically.
• 99.9% uptime SLA.
• Easy multi-region deployment: Add regions with a single command.
• Sprites for AI workloads: Infrastructure purpose-built for the agentic AI era.
• Strong developer community: Active forum and Discord with detailed guides for most frameworks.

Cons

• Heavy CLI reliance: The Web UI is minimal. Developers who prefer a polished dashboard (like DigitalOcean's) may find this frustrating.
• Complex pricing: Per-second billing is harder to reason about than flat monthly VPS rates. Budget alerts are essential.
• First-boot cold start: Creating a Machine for the first time (image pull + filesystem build) takes low double-digit seconds.
• Limited managed services: Only Postgres is managed. No managed Redis, Kafka, or Elasticsearch — unlike DigitalOcean or AWS.
• Higher cost vs. raw VPS: For pure compute per dollar, Hetzner is significantly cheaper.
• Free-tier support is slow: Community support only for Hobby accounts; priority support requires a paid plan.

Fly.io vs. DigitalOcean vs. Hetzner

Data as of October 2026. Verify current pricing directly with each provider.

Verdict: Who Should Use Fly.io?

Fly.io is a great fit if you are…

• A developer who already uses Docker and wants the fastest path from Dockerfile to production
• Building a side project or early-stage startup and want to start for free
• Running apps with uneven traffic patterns where scale-to-zero saves real money
• A full-stack developer using Next.js, Remix, Elixir/Phoenix, or Astro
• Building AI agent infrastructure and need persistent, checkpointable compute
• Wanting to serve a global audience with automatic edge routing

Consider alternatives if you need…

• A polished web UI → DigitalOcean or Bangmod Cloud
• Maximum raw compute per dollar → Hetzner
• Managed Redis, Kafka, or Elasticsearch → DigitalOcean or AWS
• Thai-language support → AsiaGB, Bangmod Cloud, or local Thai providers

Frequently Asked Questions