Softwr

Cloud · head to head

Fly.io vs Linkerd

Fly.io logo

Fly.io

Cloud

Deploy web applications globally

From
$29/month
Rated
-
Full reviewWebsite
Linkerd logo

Linkerd

Cloud

Lightweight service mesh for Kubernetes

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Linkerd has a free tier, so it costs nothing to try first.
  • Each has a real cost: 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; Linkerd deliberately fewer features than Istio, so complex routing and multi-cluster policy can hit its limits
  • They diverge on capability: Fly.io covers Global deployment, Linkerd covers Automatic mutual TLS.

Where they differ

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

Attributes where Fly.io and Linkerd differ
AttributeFly.ioLinkerd
Starting price$29/monthFree
Pricing modelusage-basedOpen source, no licence fee
Free tierNoYes
PlatformsWeb, Api, DockerKubernetes, Linux
Founded2020Unknown

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

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 Fly.io

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

Only in Linkerd

  • Automatic mutual TLS
  • Golden metrics
  • Rust micro-proxy
  • Traffic policy

What people use each for

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

Fly.io

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

Linkerd

  • Adding mutual TLS between services to satisfy a compliance requirementnot Fly.io
  • Getting per-service latency and success rates without instrumenting applicationsnot Fly.io
  • Progressive delivery with traffic splitting during rolloutsnot Fly.io

Where each one falls short

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

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

Linkerd

  • Deliberately fewer features than Istio, so complex routing and multi-cluster policy can hit its limits
  • Kubernetes only, with no story for workloads outside a cluster
  • A sidecar per pod is still real memory and latency overhead, however small, and a mesh is another layer to debug during incidents

Pricing, plan by plan

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

Linkerd

Free
  • LinkerdFree
    • Full functionality
    • No usage limits
    • Community support

Which should you pick?

Choose Fly.io if

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

Choose Linkerd if

  • You need automatic mutual tls.
  • You want to start without paying.
  • You work on Kubernetes, Linux.
  • You also want golden metrics.
Linkerd review

Questions people ask

Is Fly.io or Linkerd better?
Neither clearly leads. Fly.io starts at $29/month and Linkerd at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Fly.io or Linkerd?
Linkerd has a free tier; the other does not. Paid plans start at $29/month for Fly.io and Free for Linkerd.
Does Fly.io or Linkerd run on more platforms?
Fly.io runs on Web, Api, Docker. Linkerd runs on Kubernetes, Linux.
Can I use Linkerd for free?
Yes. Linkerd has a free tier, so you can try it without paying. Fly.io starts at $29/month.
What is Fly.io best used for?
Fly.io is most often used for deploying containerised applications close to users across regions, running full stack apps and databases on managed machines. Of those, deploying containerised applications close to users across regions and running full stack apps and databases on managed machines are not what Linkerd is typically brought in for.
What can Fly.io do that Linkerd cannot?
Fly.io covers Global deployment, Docker support, Postgres databases, Redis support. Linkerd covers Automatic mutual TLS, Golden metrics, Rust micro-proxy, Traffic policy.

Answered from the vendors’ own pages

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
Linkerd: Is Linkerd free?

The open-source project is free. Buoyant, its maintainer, sells enterprise distributions and support separately.

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
Linkerd: Linkerd or Istio?

Linkerd trades features for simplicity, with a smaller proxy and far less configuration. Istio is more capable and correspondingly more work to run.

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
Linkerd: Do I need a service mesh at all?

Only if you need mutual TLS, uniform retries or per-service traffic metrics across many services. For a handful of services it is usually more machinery than the problem justifies.

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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