Heroku vs Fly.io — The Old Guard vs The Upstart Contender

Heroku's simplicity is legendary, but Fly.io's global edge and aggressive pricing make it the pick for modern apps that need speed without the bloat.

The Framing: Managed PaaS vs Edge-First Hosting

Heroku is the managed PaaS that defined 'easy deployments' for a decade—you push code, it runs. Fly.io is the edge-first hosting platform that takes that simplicity and layers on global distribution and lower costs. They're both aiming for developers who hate DevOps, but Fly.io is built for a world where latency matters and every dollar counts.

Heroku's philosophy is 'abstract everything away,' which is great until you hit its limits and the bill arrives. Fly.io's approach is 'give you control without the complexity'—you get VMs, but they're managed like containers, and they're deployed globally by default. It's not a direct feature-for-feature clone; it's a rethinking of what PaaS should be in 2023.

Where Fly.io Wins

Fly.io's global edge network is its killer feature. Deployments automatically run in multiple regions (like Dallas, Amsterdam, Sydney), and requests are routed to the nearest one. For a Heroku app, you're stuck in one region (e.g., US East) unless you pay for Private Spaces and set up complex routing.

Then there's pricing. Fly.io's $19/month 'Standard-1x' VM gives you 2 vCPUs, 4GB RAM, and 160GB storage. Heroku's closest equivalent, the 'Standard-2x' dyno, costs $50/month for 1 vCPU, 2.5GB RAM, and ephemeral storage. That's half the resources for more than double the price. Fly.io also includes a free tier with 3 shared-cpu VMs, while Heroku's free tier is being phased out.

Where Heroku Holds Its Own

Heroku's ecosystem is still unmatched. Its add-on marketplace has 200+ services (like databases, monitoring, logging) that integrate with one click. Need Postgres? Click 'Heroku Postgres' and it's attached. Fly.io has add-ons, but it's a shorter list—you might need to self-manage or use external services.

Heroku's developer experience is polished. The CLI is intuitive, the dashboard is clean, and features like Review Apps (spin up per-PR environments) are built-in. Fly.io's CLI is powerful but more technical, and its dashboard is functional but not as slick. If you value 'it just works' over raw performance, Heroku has the edge here.

The Gotchas and Switching Costs

Switching from Heroku to Fly.io isn't a simple lift-and-shift. Heroku uses buildpacks to auto-detect and run your app (e.g., Ruby, Node.js). Fly.io requires a Dockerfile or a similar configuration. If you're not containerized, you'll need to learn Docker basics—that's a real friction point for teams used to Heroku's magic.

Fly.io's documentation is good but can be terse. Heroku's docs are comprehensive and beginner-friendly. Also, Fly.io is younger, so you might hit edge cases or need to rely more on community support. Heroku has a decade of stability, but that comes with the baggage of legacy pricing and slower innovation.

If You're Starting Today...

Start with Fly.io if you're building a new app. Use its free tier to prototype, then scale to paid VMs as needed. The global edge means better performance for users worldwide, and the cost savings add up fast. For a typical Node.js app, you'll pay $19/month on Fly.io vs $50+ on Heroku for better specs.

Only pick Heroku if you're in a large org that needs its add-on ecosystem or if you're allergic to Docker. But even then, consider that Fly.io's price advantage might justify the learning curve. For greenfield projects, Fly.io is the default choice—it's where the industry is heading.

What Most Comparisons Get Wrong

Most reviews treat these as equal PaaS options. They're not. Heroku is a full-stack platform that handles everything from builds to databases. Fly.io is a hosting layer—you bring your own Docker containers, and it runs them globally. This means Fly.io gives you more control (e.g., you can run any stack, not just supported languages) but less hand-holding.

The real question isn't 'which is easier?'—it's 'how much control do you want?' Heroku abstracts away the infrastructure, but you pay for that abstraction in dollars and flexibility. Fly.io puts you closer to the metal, which is cheaper and faster, but requires a bit more setup. For most modern apps, that trade-off is worth it.

Quick Comparison

Factor	Heroku	Fly Io
Pricing (Basic Tier)	$50/month for Standard-2x dyno (1 vCPU, 2.5GB RAM)	$19/month for Standard-1x VM (2 vCPUs, 4GB RAM)
Free Tier	Being phased out; limited to 550-1000 dyno hours/month	3 shared-cpu VMs, 3GB storage, 160GB outbound data
Global Regions	Single region per app (e.g., US East); multi-region requires Private Spaces ($/month)	Automatic multi-region deployment (e.g., Dallas, Amsterdam, Sydney)
Deployment Method	Buildpacks (auto-detects languages like Ruby, Node.js)	Dockerfile or similar (requires containerization)
Add-on Marketplace	200+ integrated services (e.g., Heroku Postgres, Redis)	Limited add-ons (e.g., Upstash Redis); more self-managed options
Max RAM per Instance	14GB (on Performance-L dyno, $500/month)	64GB (on Dedicated-8x VM, custom pricing)
CLI Experience	Polished, intuitive (e.g., `heroku create`, `git push heroku`)	Powerful but technical (e.g., `fly launch`, `fly deploy`)
Data Persistence	Ephemeral dyno storage; persistent data via add-ons (extra cost)	Persistent volumes included (e.g., 160GB on Standard-1x)

The Verdict

Use Heroku if: You're in an enterprise that relies on Heroku's add-on ecosystem or you need zero-Docker deployments for a legacy app.

Use Fly Io if: You're building a new app where cost, global performance, and control over the stack matter more than hand-holding.

Consider: Railway—if you want Heroku's simplicity with modern pricing and Docker support, but don't need Fly.io's edge network.

Heroku vs Fly Io: FAQ

Is Heroku or Fly Io better?

Fly.io is the Nice Pick. Fly.io wins on price and performance. It's half the cost of Heroku for similar specs, and its global edge network means your app loads faster everywhere—not just in one region.

When should you use Heroku?

You're in an enterprise that relies on Heroku's add-on ecosystem or you need zero-Docker deployments for a legacy app.

When should you use Fly Io?

You're building a new app where cost, global performance, and control over the stack matter more than hand-holding.

What's the main difference between Heroku and Fly Io?

Heroku's simplicity is legendary, but Fly.io's global edge and aggressive pricing make it the pick for modern apps that need speed without the bloat.

How do Heroku and Fly Io compare on pricing (basic tier)?

Heroku: $50/month for Standard-2x dyno (1 vCPU, 2.5GB RAM). Fly Io: $19/month for Standard-1x VM (2 vCPUs, 4GB RAM). Fly Io wins here.

Are there alternatives to consider beyond Heroku and Fly Io?

Railway—if you want Heroku's simplicity with modern pricing and Docker support, but don't need Fly.io's edge network.

The Bottom Line

Fly.io wins

Fly.io wins on price and performance. It's half the cost of Heroku for similar specs, and its global edge network means your app loads faster everywhere—not just in one region.

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