Softwr

Design · head to head

Principle vs Proto.io

P

Principle

Design

Animate your ideas, design better apps

From
$129/one-time
Rated
-
Full reviewWebsite
Proto.io logo

Proto.io

Design

Hosted high-fidelity prototyping with device preview and no code

From
On request
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Principle macOS only with no Windows or Linux editor available; 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.
  • They diverge on capability: Principle covers Timeline-based animation, Proto.io covers Event and condition system.
  • Prices and features above were last checked on 31 August 2026.

Where they differ

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

Attributes where Principle and Proto.io differ
AttributePrincipleProto.io
Starting price$129/one-timeOn request
Pricing modelUnknownPer user per month
PlatformsmacOSWeb, iOS, Android
Founded2015Unknown

Identical on both: free tier (No), 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 Principle

  • Timeline-based animation
  • Interactive prototypes
  • Touch gestures
  • Component reuse
  • Video export
  • Sketch import
  • Figma import
  • Driver animations

Only in Proto.io

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

What people use each for

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

Principle

  • Mobile app prototypesnot Proto.io
  • Micro-interactionsnot Proto.io
  • Animation designnot Proto.io
  • User flow designnot Proto.io
  • Gesture-based interfacesnot Proto.io

Proto.io

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

Where each one falls short

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

Principle

  • macOS only with no Windows or Linux editor available
  • No vector morphing capability for complex shape transformations
  • Limited asset creation tools; cannot create vectors or shapes directly within Principle
  • Sketch import flattens certain properties including paths, fills, borders, masks, blur effects, and text layers
  • Limited variable support, logical loops, and data input capabilities compared to tools like ProtoPie or Origami

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.

Pricing, plan by plan

Principle

$129/one-time
  • License$129/one-time
    • One year of upgrades
    • Full access to all features
  • Upgrade License$99/year
    • Annual renewal for ongoing upgrades

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

Which should you pick?

Choose Principle if

  • You need timeline-based animation.
  • You work on macOS.
  • You also want interactive prototypes.
Principle review

Choose Proto.io if

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

Questions people ask

Is Principle or Proto.io better?
Neither clearly leads. Principle starts at $129/one-time and Proto.io at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Principle or Proto.io?
Principle starts at $129/one-time and Proto.io at On request.
Does Principle or Proto.io run on more platforms?
Principle runs on macOS. Proto.io runs on Web, iOS, Android.
What is Principle best used for?
Principle is most often used for mobile app prototypes, micro-interactions, animation design, user flow design. Of those, mobile app prototypes and micro-interactions are not what Proto.io is typically brought in for.
What can Principle do that Proto.io cannot?
Principle covers Timeline-based animation, Interactive prototypes, Touch gestures, Component reuse. Proto.io covers Event and condition system, Timeline animation, Device preview, Component library.

Answered from the vendors’ own pages

Principle: Does Principle run on Windows or Linux?

No. Principle is macOS only and runs on Intel and Apple Silicon Macs. There is no Windows or Linux editor available; however, prototypes can be shared and viewed on any platform via web link.

Source
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.

Principle: What is the cost of Principle?

Principle costs $129 for a one-time purchase with 1 year of upgrades included. After 1 year, upgrade licenses cost $99/year. A 14-day free trial is available with all features included.

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.

Principle: Can I import designs from Figma or Sketch into Principle?

Yes. Principle supports importing designs from Figma and Sketch with intelligent merging of re-imported files. Some Sketch properties such as paths, fills, borders, blur effects, masks, and text layers are flattened upon import.

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.

Principle: How do I share Principle prototypes with others?

Prototypes can be shared via web link with one click (File > Export > Share to Web). Recipients can view and interact with prototypes in any browser on any platform: Windows, macOS, Linux, Android, or iOS. No installation required.

Source
Principle: Can I create vector shapes and morphing animations in Principle?

Principle does not support vector morphing, where vector objects transform into other vector shapes. It also has limited asset creation capabilities and editing is restricted to basic operations like scale and rotate.

Source
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