Softwr

Cloud · head to head

Fly.io vs Stable Diffusion

Fly.io logo

Fly.io

Cloud

Deploy web applications globally

From
$29/month
Rated
-
Full reviewWebsite
Stable Diffusion logo

Stable Diffusion

AI

Open-source AI image generation

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Stable Diffusion 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; Stable Diffusion generated images have lower resolution and quality at non-standard dimensions
  • They diverge on capability: Fly.io covers Global deployment, Stable Diffusion covers Text-to-image.

Where they differ

Only the attributes on which Fly.io and Stable Diffusion actually diverge.

Attributes where Fly.io and Stable Diffusion differ
AttributeFly.ioStable Diffusion
Starting price$29/monthFree
Pricing modelusage-basedUnknown
Free tierNoYes
PlatformsWeb, Api, DockerWeb, Local (GPU-based), Cloud APIs
CategoryCloudAI
Founded20202019

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 Fly.io

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

Only in Stable Diffusion

  • Text-to-image
  • Image-to-image
  • Inpainting
  • LoRA support
  • ComfyUI
  • Automatic1111
  • Multiple UIs
  • Local support

Both cover

  • Web support
  • Api support

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 Stable Diffusion
  • Running full stack apps and databases on managed machinesnot Stable Diffusion

Stable Diffusion

  • ai tools managementnot Fly.io
  • Workflow automationnot Fly.io
  • Reportingnot 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

Stable Diffusion

  • Generated images have lower resolution and quality at non-standard dimensions
  • Struggles with complex multi-object prompts and text generation
  • Poor rendering of human hands, limbs, and faces due to training data limitations
  • Trained primarily on English-language descriptions, reinforcing Western cultural bias
  • Requires significant GPU computational resources for local deployment

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

Stable Diffusion

Free

No published plan breakdown. See the Stable Diffusion review.

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 Stable Diffusion if

  • You need text-to-image.
  • You want to start without paying.
  • You work on Web, Local (GPU-based), Cloud APIs.
  • You also want image-to-image.
Stable Diffusion review

Questions people ask

Is Fly.io or Stable Diffusion better?
Neither clearly leads. Fly.io starts at $29/month and Stable Diffusion at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Fly.io or Stable Diffusion?
Stable Diffusion has a free tier; the other does not. Paid plans start at $29/month for Fly.io and Free for Stable Diffusion.
Does Fly.io or Stable Diffusion run on more platforms?
Fly.io runs on Web, Api, Docker. Stable Diffusion runs on Web, Local (GPU-based), Cloud APIs.
Can I use Stable Diffusion for free?
Yes. Stable Diffusion 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 Stable Diffusion is typically brought in for.
What can Fly.io do that Stable Diffusion cannot?
Fly.io covers Global deployment, Docker support, Postgres databases, Redis support. Stable Diffusion covers Text-to-image, Image-to-image, Inpainting, LoRA support. Both handle Web support, Api support.

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
Stable Diffusion: Is Stable Diffusion truly free and open-source?

Yes. Stable Diffusion is released under the CreativeML Open RAIL-M license, allowing free use for both commercial and non-commercial purposes, and the code is open-source on GitHub.

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
Stable Diffusion: Can I use Stable Diffusion commercially for free?

Yes, if your organization has less than $1M annual revenue. Organizations exceeding $1M annually must obtain an Enterprise License from Stability AI.

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
Stable Diffusion: What are Stable Diffusion's image resolution limitations?

The base model was trained on 512x512 pixel images, and image quality degrades noticeably when deviating from this resolution. Newer models like SDXL support higher resolutions.

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
Stable Diffusion: Can I run Stable Diffusion locally on my computer?

Yes. Stable Diffusion is open-source and can run locally on compatible hardware, though it requires a GPU for reasonable performance.

Source
Share

Related pages

More on Fly.io

More on Stable Diffusion

Keep looking

Other head to heads