Fly

Global application platform for running containers close to users with low latency.

Overview

Fly.io is a cloud platform designed to run applications globally with minimal operational overhead. It provides hardware-isolated Linux virtual machines (Machines and Sprites) that can be deployed across 18+ regions worldwide, with automatic checkpointing, persistent storage, and sub-second boot times.

The platform emphasizes developer experience through its CLI-first approach (flyctl), support for multiple languages and frameworks (Rails, Django, Laravel, Phoenix, JavaScript, Rust, Python, and more), and managed services like Postgres, Kubernetes, and GPU support. Fly.io is particularly focused on AI agents and untrusted code execution, offering isolated environments with egress policies and automatic resource cleanup.

Billing is usage-based with no complex plans—you pay only for what you use. The platform includes features like private networking, autoscaling, zero-downtime deploys, and a support team composed of engineers rather than chatbots.

Key features

Hardware-isolated Linux VMs (Machines and Sprites)
Global deployment across 18+ regions
Persistent block device storage with automatic checkpointing
Managed Postgres database
Fly Kubernetes support
GPU machine support
Private networking and custom domains
Zero-downtime deploys
Autoscaling
MCP server hosting with egress policies

Pros

Sub-second machine boot times (18ms typical)
Usage-based billing with no complex plans
Support team composed of engineers, not chatbots
Automatic checkpointing for stateful workloads
Persistent storage scales to 100GB automatically
Granular permission controls via connectors
Multi-region deployment without rewriting infrastructure
Free tier available with community support

Cons

Sprite Block Device currently in private beta
Learning curve for developers new to containerized deployments
Requires understanding of flyctl CLI for full feature access
Support plans start at $29/month for guaranteed response times

Use this if

You need to deploy applications globally with minimal DevOps overhead, run AI agents in isolated environments, or require managed databases and persistent storage across multiple regions.

Skip this if

You prefer traditional serverless platforms without container management, need on-premises deployment only, or require a completely free tier without any paid support options.

Best for

Deploying web applications globallyRunning AI agents and untrusted codeMicroservices and multi-region setupsTeams needing managed Postgres and storageDevelopers seeking minimal DevOps overheadBuilding agent-powered applications

Alternatives

HerokuAWS EC2 with ECSGoogle Cloud RunDigitalOcean App PlatformRailwayRender

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