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Developer Tools · head to head

CodeSandbox vs Fly.io

C

CodeSandbox

Developer Tools

Cloud platform for instant, isolated development sandboxes and code execution

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 CodeSandbox has a free tier, so it costs nothing to try first.
  • Each has a real cost: CodeSandbox detailed paid plan pricing was not published on the accessible pages, making cost comparison difficult.; 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
  • They diverge on capability: CodeSandbox covers Instant sandboxes, Fly.io covers Global deployment.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

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

Attributes where CodeSandbox and Fly.io differ
AttributeCodeSandboxFly.io
Starting priceFree$29/month
Pricing modelfreemiumusage-based
Free tierYesNo
Platformsweb, apiWeb, 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 CodeSandbox

  • Instant sandboxes
  • Programmatic sandbox API
  • Secure isolated execution
  • Browser-based editor
  • CI/CD sandbox support
  • Scalable VM infrastructure

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.

CodeSandbox

  • Running AI agent-generated code safely in isolationnot Fly.io
  • Prototyping and sharing web projects in-browsernot Fly.io
  • Executing untrusted code for a code playground productnot Fly.io
  • Using sandboxes as ephemeral CI/CD build environmentsnot Fly.io

Fly.io

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

Where each one falls short

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

CodeSandbox

  • Detailed paid plan pricing was not published on the accessible pages, making cost comparison difficult.
  • Focus has shifted toward programmatic sandbox infrastructure, which may be less approachable for casual users just wanting a quick online editor.
  • Public sandboxes are visible to others by default, which is not ideal for proprietary code.

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

CodeSandbox

Free
  • FreeFree
    • Public sandboxes
    • Basic sandbox usage

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 CodeSandbox if

  • You need instant sandboxes.
  • You want to start without paying.
  • You work on web, api.
  • You also want programmatic sandbox api.
CodeSandbox 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 CodeSandbox or Fly.io better?
Neither clearly leads. CodeSandbox 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, CodeSandbox or Fly.io?
CodeSandbox has a free tier; the other does not. Paid plans start at Free for CodeSandbox and $29/month for Fly.io.
Does CodeSandbox or Fly.io run on more platforms?
CodeSandbox runs on web, api. Fly.io runs on Web, Api, Docker.
Can I use CodeSandbox for free?
Yes. CodeSandbox has a free tier, so you can try it without paying. Fly.io starts at $29/month.
What is CodeSandbox best used for?
CodeSandbox is most often used for running ai agent-generated code safely in isolation, prototyping and sharing web projects in-browser, executing untrusted code for a code playground product, using sandboxes as ephemeral ci/cd build environments. Of those, running ai agent-generated code safely in isolation and prototyping and sharing web projects in-browser are not what Fly.io is typically brought in for.
What can CodeSandbox do that Fly.io cannot?
CodeSandbox covers Instant sandboxes, Programmatic sandbox API, Secure isolated execution, Browser-based editor. Fly.io covers Global deployment, Docker support, Postgres databases, Redis support.

Answered from the vendors’ own pages

CodeSandbox: Does CodeSandbox offer a free tier?

Yes, CodeSandbox offers a free option available on the platform. Users can start for free.

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
CodeSandbox: Where can I find CodeSandbox's pricing details?

CodeSandbox maintains a dedicated pricing page, but specific tier names, feature breakdowns, and costs are not displayed on the landing page.

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
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
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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