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Design · head to head

Proto.io vs Spline

Proto.io logo

Proto.io

Design

Hosted high-fidelity prototyping with device preview and no code

From
On request
Rated
-
Full reviewWebsite
Spline logo

Spline

Design

3D design tool for the web

From
Free
Rated
-
Full reviewWebsite

The short version

  • Only Spline has a free tier, so it costs nothing to try first.
  • Each has a real cost: Proto.io prototypes live in the vendor cloud and offline export is a higher-tier feature, so the ability to archive completed client work is a plan-level decision rather than a given.; Spline aI generation features produce inconsistent and often distorted results, failing at basic depth perception tasks
  • They diverge on capability: Proto.io covers Event and condition system, Spline covers 3D modeling.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

Only the attributes on which Proto.io and Spline actually diverge.

Attributes where Proto.io and Spline differ
AttributeProto.ioSpline
Starting priceOn requestFree
Pricing modelPer user per monthfreemium
Free tierNoYes
PlatformsWeb, iOS, AndroidWeb, iOS, Android, visionOS
FoundedUnknown2020

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

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 Proto.io

  • Event and condition system
  • Timeline animation
  • Device preview
  • Component library
  • User testing integration
  • Design import

Only in Spline

  • 3D modeling
  • Real-time collaboration
  • Animations
  • Interactions
  • Code export
  • React
  • Next.js
  • Webflow

What people use each for

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

Proto.io

  • Running usability tests where the prototype must respond to real input rather than replay a fixed click pathnot Spline
  • Demonstrating a form-heavy or data-driven flow to stakeholders before any code existsnot Spline
  • Testing a mobile interaction on the physical device it is designed for, with correct gesture behaviournot Spline
  • Validating a concept for a client who needs to feel the product, not watch a video of itnot Spline

Spline

  • Web 3D experiencesnot Proto.io
  • Interactive prototypesnot Proto.io
  • Product visualizationnot Proto.io

Where each one falls short

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

Proto.io

  • Prototypes live in the vendor cloud and offline export is a higher-tier feature, so the ability to archive completed client work is a plan-level decision rather than a given.
  • Design is done elsewhere and interaction is rebuilt here, so every change to the visual design has to be reapplied by hand and the two artefacts drift apart.
  • The event and condition model is layer based, so a genuinely complex flow becomes a large tree of triggers that nobody but its author can audit.
  • Editor seats are priced individually and viewer access is limited on lower plans, so opening review to a wide stakeholder group pushes you up a tier for people who never edit anything.
  • The market standardised on Figma, so hiring people who already know Proto.io is progressively harder and every new researcher is a training cost.

Spline

  • AI generation features produce inconsistent and often distorted results, failing at basic depth perception tasks
  • Limited to simpler designs - not suitable for high-poly, detailed production models
  • Performance degrades with complex scenes containing many objects and materials
  • Limited non-Apple platform coverage compared to cross-platform design tools
  • Tutorials are either too fast for beginners or too basic for advanced users

Pricing, plan by plan

Proto.io

On request
  • Freelancer$undefined/month
    • Single editor
    • Limited active projects
    • Standard sharing
  • Startup$undefined/month
    • Multiple editors
    • More projects
    • Team library
  • Agency$undefined/month
    • Higher project and storage limits
    • Client sharing controls
  • Corporate$undefined/month
    • Largest quotas
    • Offline export on higher tiers
    • Priority support

Spline

Free
  • FreeFree
    • Unlimited projects
    • Basic exports
    • Community support
  • Pro$9/month
    • Advanced exports
    • Custom domains
    • Password protection
  • Team$19/month
    • Team collaboration
    • Version control
    • Admin controls

Which should you pick?

Choose Proto.io if

  • You need event and condition system.
  • You work on Web, iOS, Android.
  • You also want timeline animation.
Proto.io review

Choose Spline if

  • You need 3d modeling.
  • You want to start without paying.
  • You work on Web, iOS, Android, visionOS.
  • You also want real-time collaboration.
Spline review

Questions people ask

Is Proto.io or Spline better?
Neither clearly leads. Proto.io starts at On request and Spline at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Proto.io or Spline?
Spline has a free tier; the other does not. Paid plans start at On request for Proto.io and Free for Spline.
Does Proto.io or Spline run on more platforms?
Proto.io runs on Web, iOS, Android. Spline runs on Web, iOS, Android, visionOS.
Can I use Spline for free?
Yes. Spline has a free tier, so you can try it without paying. Proto.io starts at On request.
What is Proto.io best used for?
Proto.io is most often used for running usability tests where the prototype must respond to real input rather than replay a fixed click path, demonstrating a form-heavy or data-driven flow to stakeholders before any code exists, testing a mobile interaction on the physical device it is designed for, with correct gesture behaviour, validating a concept for a client who needs to feel the product, not watch a video of it. Of those, running usability tests where the prototype must respond to real input rather than replay a fixed click path and demonstrating a form-heavy or data-driven flow to stakeholders before any code exists are not what Spline is typically brought in for.
What can Proto.io do that Spline cannot?
Proto.io covers Event and condition system, Timeline animation, Device preview, Component library. Spline covers 3D modeling, Real-time collaboration, Animations, Interactions.

Answered from the vendors’ own pages

Proto.io: Can it replace Figma?

No. It has no design system or file-handoff role. It sits alongside Figma for the prototypes Figma cannot express.

Spline: What is Spline's pricing?

Spline offers a Free plan with watermarked web exports, Starter at $12/month (billed annually) removing watermarks, Professional at $20/month with unlimited projects, and Enterprise with custom pricing. Viewers are unlimited on all plans.

Source
Proto.io: What happens to prototypes if we stop paying?

They stop being accessible unless you have exported them, and offline export is restricted to higher plans, so plan archiving before you cancel.

Spline: Can Spline export 3D models to other tools?

Spline's export/import format support is more limited compared to traditional 3D tools like Blender. It focuses on web-first exports and native app code generation.

Source
Proto.io: Is it worth learning now that InVision has gone?

If your work is usability research on conditional flows, yes. If you need click-through demos of static screens, Figma already does that at no extra cost.

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