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Developer Tools · head to head

Deno vs Fly.io

Deno logo

Deno

Developer Tools

A fast, open-source, fully Node-compatible JS runtime with TypeScript baked right in

From
Free
Free plan
Yes
Full reviewWebsite
Fly.io logo

Fly.io

Cloud

Deploy web applications globally

From
$29/month
Free plan
No
Full reviewWebsite

The short version

  • Only Deno has a free tier, so it costs nothing to try first.
  • Each has a real cost: Deno egress bandwidth overage costs $0.20/GB which can become expensive for high-traffic applications; Fly.io egress is priced by destination region, from $0.02 per GB in North America and Europe to $0.12 per GB for Africa and India, so the same traffic costs six times more depending on where users are
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which Deno and Fly.io actually diverge.

Attributes where Deno and Fly.io differ
AttributeDenoFly.io
Starting priceFree$29/month
Pricing modelfreemiumusage-based
Free tierYesNo
PlatformsWebWeb, Api, Docker
CategoryDeveloper ToolsCloud
FoundedUnknown2020

Identical on both: user rating (Not yet rated).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Deno

Nothing recorded that Fly.io does not also cover.

Only in Fly.io

  • Global deployment
  • Docker support
  • Postgres databases
  • Redis support
  • Auto-scaling
  • Health checks
  • Backups
  • Monitoring

What people use each for

The jobs each tool is most often brought in to do.

Deno

  • Running TypeScript natively without transpilation overheadnot Fly.io
  • Migrating Node.js applications to secure-by-default runtimenot Fly.io
  • Deploying edge functions and serverless containers seamlesslynot Fly.io
  • Consolidating developer tools into single binarynot Fly.io

Fly.io

  • Deploying containerised applications close to users across regionsnot Deno
  • Running full stack apps and databases on managed machinesnot Deno

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Deno

  • Egress bandwidth overage costs $0.20/GB which can become expensive for high-traffic applications
  • CPU time overage is $0.10/hour on Pro and Builder tiers, adding to costs for compute-intensive workloads
  • Enterprise pricing is not disclosed; requires sales contact

Fly.io

  • Egress is priced by destination region, from $0.02 per GB in North America and Europe to $0.12 per GB for Africa and India, so the same traffic costs six times more depending on where users are
  • Stopped machines still bill at $0.15 per GB of root filesystem a month, so a paused service is not a free one
  • Volumes are billed on provisioned capacity rather than usage, at $0.15 per GB a month
  • Reservation discounts of 40% require paying a year up front, from $36 to $1,440
  • Fly Kubernetes is a separate $75 a month per cluster
  • Dedicated IPv4 addresses are $2 a month each

Pricing, plan by plan

Deno

Free
  • FreeFree
    • 1 million requests/month
    • 20GB egress bandwidth
    • 10 apps
  • Pro$20/month
    • 5 million requests/month
    • 200GB egress
    • 50 apps
  • Builder$200/month
    • 25 million requests/month
    • 2,000GB egress
    • 10,000 apps
  • Enterprise$null/month
    • Custom limits on all metrics
    • 99.95% reliability SLA
    • Email support with SLA

Fly.io

$29/month
  • Pay-as-You-Go$null/mo
    • Micro VMs and persistent storage charged by usage
    • FlyCTL CLI
    • Unlimited users and organizations
  • Serious Support$29/month
    • Access to dedicated engineering team
    • All Pay-as-You-Go features
  • Machine Reservation Blocks$null/mo
    • 40% discount on machine usage
    • Requires upfront payment for savings
  • Compliance Package$99/month
    • HIPAA compliance
    • BAAs
    • SOC2 documentation

Which should you pick?

Choose Deno if

  • You want to start without paying.
Deno review

Choose Fly.io if

  • You need global deployment.
  • You work on Web, Api, Docker.
  • You also want docker support.
Fly.io review

Questions people ask

Is Deno or Fly.io better?
Neither clearly leads. Deno starts at Free and Fly.io at $29/month, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Deno or Fly.io?
Deno has a free tier; the other does not. Paid plans start at Free for Deno and $29/month for Fly.io.
Does Deno or Fly.io run on more platforms?
Deno runs on Web. Fly.io runs on Web, Api, Docker.
Can I use Deno for free?
Yes. Deno has a free tier, so you can try it without paying. Fly.io starts at $29/month.
What is Deno best used for?
Deno is most often used for running typescript natively without transpilation overhead, migrating node.js applications to secure-by-default runtime, deploying edge functions and serverless containers seamlessly, consolidating developer tools into single binary. Of those, running typescript natively without transpilation overhead and migrating node.js applications to secure-by-default runtime are not what Fly.io is typically brought in for.
What can Deno do that Fly.io cannot?
Fly.io covers Global deployment, Docker support, Postgres databases, Redis support.

Answered from the vendors’ own pages

Deno: How much does Deno Deploy cost?

Deno Deploy offers a free tier at $0/month, Pro at $20/month, and Builder at $200/month. Enterprise has custom pricing. All plans include base request and bandwidth limits, with overage charges for additional usage.

Source
Fly.io: Is there a free tier for Fly.io?

Fly.io does not advertise a free tier. The base plan is pay-as-you-go with usage-based pricing for Micro VMs and persistent storage. All users get FlyCTL CLI, unlimited organizations, private networking, SSO, ACLs, and scoped tokens.

Source
Deno: What are Deno Deploy's overage charges?

Egress bandwidth overages cost $0.20 per GB. CPU time overages are $0.10 per hour on Pro and Builder tiers. Memory time and KV database operations also incur charges beyond included limits.

Source
Fly.io: How much does Fly.io Serious Support cost?

Serious Support costs 29 USD per month and provides access to a dedicated engineering team while maintaining all pay-as-you-go features for Micro VMs and storage.

Source
Deno: How many apps can I deploy on Deno's free plan?

The free tier includes 10 apps with up to 1 concurrent build. Pro tier supports 50 apps with 3 concurrent builds, and Builder supports 10,000 apps with 20 concurrent builds.

Source
Fly.io: What does Fly.io Compliance Package include?

The Compliance Package is 99 USD per month and includes HIPAA compliance, BAAs, and SOC2 documentation for organizations requiring compliance certifications.

Source
Deno: How many team members can access Deno Deploy?

The free tier supports up to 3 team members. Pro supports 10 team members. Builder supports 25 team members. Enterprise has custom seat limits.

Source
Fly.io: Does Fly.io offer discounts for upfront commitment?

Yes, Fly.io offers Machine Reservation Blocks with 40% discount on machine usage. This requires upfront payment but applies savings on infrastructure costs.

Source
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