Fly.io vs Coolify for Solo Developers

Quick Comparison

Fly.io Overview

Fly.io runs your Docker containers as micro VMs distributed across edge servers worldwide. The platform handles deployment, networking, TLS, and multi-region distribution through a CLI-first workflow. You configure your app in a fly.toml file, deploy with fly deploy, and your container runs across whichever regions you specify.

The global-first architecture is what sets Fly.io apart. Your app can run in 30+ regions simultaneously, putting compute close to users everywhere. You also get managed Postgres, persistent volumes, private networking, and a free tier with 3 shared VMs.

The tradeoff is that Fly.io is a managed platform with managed pricing. You pay per VM, per GB of bandwidth, and per GB of storage. For multiple projects, costs can add up.

Coolify Overview

Coolify is an open-source, self-hosted PaaS that turns any VPS into your own hosting platform. Install it on a server, and you get a web dashboard for deploying applications, databases, and services. Think of it as running your own Heroku or Railway on hardware you control.

The project supports Docker, Docker Compose, Nixpacks, and static sites. It handles SSL certificates, GitHub integration, one-click database provisioning, and automatic deployments. The v4 release improved the UI significantly and added features like server monitoring, webhook triggers, and multi-server support.

Because Coolify runs on your own infrastructure, you pay only for the server. A $10/month Hetzner or DigitalOcean VPS running Coolify can host 5-10 small projects comfortably. That's the core appeal for solo developers managing multiple apps.

Key Differences

Hosting model. Fly.io is a managed platform where you rent their infrastructure. Coolify is software you install on infrastructure you own. With Fly.io, you're a tenant. With Coolify, you're the landlord. This affects everything from pricing to reliability to control.

Global distribution. Fly.io can deploy your app to 30+ regions with a config change. Coolify deploys to whatever servers you've connected to it. If you need global edge deployment, Fly.io has a massive architectural advantage. If your users are in one region, Coolify on a well-placed VPS performs just as well.

Cost at scale. This is where Coolify shines. Running five projects on Fly.io means paying for five sets of VMs, bandwidth, and storage. Running five projects on Coolify means they all share one server. For a solo developer with multiple side projects, Coolify's cost structure is dramatically better.

Operations burden. Fly.io manages the underlying infrastructure. Server updates, security patches, hardware failures. Not your problem. Coolify runs on your server, so you're responsible for keeping it healthy. Disk full? Your problem. Security vulnerability in the host OS? You need to patch it. Coolify makes deployment easy, but server management is still on you.

Deployment experience. Both offer GitHub integration and automatic deploys. Fly.io's CLI is more powerful for advanced operations (scaling, regions, secrets). Coolify's web dashboard is more visual and beginner-friendly. For basic deploy-on-push workflows, both work well.

Database management. Both support one-click database deployment. Fly.io's Postgres is deployed as a managed Fly app. Coolify deploys databases as Docker containers on your server. Coolify gives you more control (you can access the container directly), while Fly.io handles backups and maintenance more automatically.

Reliability. Fly.io runs on professionally managed infrastructure with redundancy. Coolify is as reliable as your VPS and your configuration. If your server goes down at 3am, Coolify doesn't page anyone. You'll find out when users tell you or when your uptime monitor fires.

When to Choose Fly.io

• Your app needs to serve users in multiple geographic regions
• You don't want to manage server infrastructure
• You need one or two apps with global distribution
• Built-in private networking between services matters
• You prefer CLI-driven workflows for deployment

When to Choose Coolify

• You're running multiple projects and want to minimize costs
• You're comfortable with basic server administration
• Your users are concentrated in one region
• Full control over your data and infrastructure matters
• You want a visual web dashboard for managing deployments

The Verdict

Fly.io and Coolify represent two very different philosophies for solo developers. Fly.io says "let us handle the infrastructure, you handle the code." Coolify says "here's a great tool to manage your own infrastructure."

If you're building one or two apps that need global performance, Fly.io is the right choice. The managed infrastructure and multi-region deployment are worth the premium. You're paying for time you don't spend on server management.

If you're a solo developer with multiple side projects and you don't mind managing a VPS, Coolify is the smarter financial play. A single $10/month server running Coolify replaces what could easily be $50-100/month on Fly.io. The setup takes an afternoon, and after that, the deployment experience is quite good.

My recommendation: use Coolify as your default hosting for most projects. Reserve Fly.io for the project that actually needs global distribution. Most solo developer projects don't need edge computing, and the cost savings from Coolify add up fast.