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.

By the Numbers (2026)

The two tools sit on opposite sides of the build-versus-buy line, so the numbers that matter are different for each. Here is the current picture, checked on 2026-05-28.

Coolify (open source, self-hosted). Latest stable release is v4.1.1, published on 2026-05-27. The project carries more than 56,000 GitHub stars and around 4,600 forks, written in PHP and licensed Apache-2.0. The self-hosted edition is free with no feature gates or user limits, and it ships over 280 one-click services covering app frameworks, databases (PostgreSQL, MySQL, MariaDB, MongoDB, Redis, ClickHouse), and supporting tools. If you would rather not run the control plane yourself, Coolify Cloud is a managed option at $5 per month for up to two connected servers, then $3 per month per additional server, with roughly 20 percent off on annual billing. You still bring your own application servers in either case.

Fly.io (managed platform, pay-as-you-go). There is no permanent free tier anymore. New accounts get a free trial of 2 VM hours or 7 days, whichever comes first, capped at 10 machines, 20GB of volume storage, and up to 2 vCPUs and 4GB of memory per machine. After that you add a card and pay for what you use. A minimal always-on app, one shared-cpu-1x machine with 256MB of RAM, runs about $2.02 per month before traffic. The 512MB size is about $3.32 and 1GB is about $5.92. Dedicated performance machines start around $32.19 per month for one CPU and 2GB. Outbound bandwidth is metered at $0.02 per GB in North America and Europe, $0.04 per GB in Asia Pacific, Oceania, and South America, and $0.12 per GB in Africa and India. Persistent volumes are $0.15 per GB per month, and paid support starts at $29 per month for the Serious Support tier.

Real Cost at Solo-Dev Scale

Numbers in isolation do not decide anything, so price out a workload a solo developer actually has. Assume five small apps, each a single 512MB instance, plus two small Postgres databases, roughly 10GB of total persistent storage, and about 100GB of outbound traffic a month split across the apps. All figures use the per-unit rates above and assume North America or Europe egress.

On Fly.io, five 512MB machines run about $3.32 each, so roughly $16.60 per month for app compute. Two small Postgres machines at a similar size add about another $6.64. The 10GB of volume storage at $0.15 per GB is about $1.50. The 100GB of egress at $0.02 per GB is about $2.00. That lands near $26.74 per month before any paid support, and the bill scales with every machine you keep running. Add a sixth or seventh project and the line items grow with it.

On Coolify, those same five apps and two databases all share one server. A single mid-size VPS in the $10 to $25 per month range comfortably hosts that workload, and the software itself is free. Call it about $15 per month for a capable instance. Adding a sixth or seventh small project usually costs nothing extra because they share the same box and the same monthly bill. If you would rather not babysit the control plane, Coolify Cloud at $5 per month plus your own VPS still comes in under the Fly.io total.

The assumptions matter. Fly.io's number drops if your apps can scale to zero between requests, and it climbs fast if you need multi-region copies or dedicated performance machines. Coolify's number is flat until you outgrow the single server, at which point you add another VPS rather than paying per app. For a solo developer stacking up side projects in one region, the self-hosted math wins by a wide margin. For one app that genuinely needs to live close to users on several continents, Fly.io's per-region deployment is doing work a single VPS cannot.

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.

Sources

All figures below were checked on 2026-05-28.

• Fly.io resource pricing (machine, bandwidth, and volume rates): https://fly.io/docs/about/pricing/
• Fly.io pricing overview and support tiers: https://fly.io/pricing/
• Fly.io free trial terms (2 VM hours or 7 days, machine and storage caps): https://fly.io/docs/about/free-trial/
• Coolify pricing (self-hosted free, Coolify Cloud tiers): https://coolify.io/pricing
• Coolify GitHub repository (stars, forks, language, license, 280-plus services): https://github.com/coollabsio/coolify
• Coolify releases (latest version v4.1.1, published 2026-05-27): https://github.com/coollabsio/coolify/releases