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Design · head to head

Linearity Curve vs Proto.io

Linearity Curve logo

Linearity Curve

Design

Professional vector design for Mac and iPad

From
Free
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

  • Only Linearity Curve has a free tier, so it costs nothing to try first.
  • Each has a real cost: Linearity Curve limited to Apple ecosystem (Mac, iPad, iPhone) with no Windows or Linux support; 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: Linearity Curve covers Vector editing, 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 Linearity Curve and Proto.io actually diverge.

Attributes where Linearity Curve and Proto.io differ
AttributeLinearity CurveProto.io
Starting priceFreeOn request
Pricing modelUnknownPer user per month
Free tierYesNo
PlatformsMac, IosWeb, iOS, Android
Founded2017Unknown

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 Linearity Curve

  • Vector editing
  • Auto Trace
  • Typography tools
  • Pen tool
  • iCloud sync
  • Adobe Creative Cloud
  • Sketch
  • Figma

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.

Linearity Curve

  • Vector illustrationnot Proto.io
  • Logo designnot Proto.io
  • UI designnot Proto.io
  • Print designnot Proto.io

Proto.io

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

Where each one falls short

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

Linearity Curve

  • Limited to Apple ecosystem (Mac, iPad, iPhone) with no Windows or Linux support
  • Requires annual or monthly subscription for commercial use, unlike competitors offering lifetime purchase options
  • Free plan is severely limited to only 3 Curve files and 5GB storage

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

Linearity Curve

Free
  • StarterFree
    • 50 lifetime credits
    • 3 Curve files
    • 5GB storage
  • Pro$11.99/month
    • 250 monthly credits
    • Unlimited files
    • 100GB storage
  • Business$65/month
    • 500 monthly credits
    • 500GB storage
    • Brand management

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 Linearity Curve if

  • You need vector editing.
  • You want to start without paying.
  • You work on Mac, Ios.
  • You also want auto trace.
Linearity Curve 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 Linearity Curve or Proto.io better?
Neither clearly leads. Linearity Curve starts at Free and Proto.io at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Linearity Curve or Proto.io?
Linearity Curve has a free tier; the other does not. Paid plans start at Free for Linearity Curve and On request for Proto.io.
Does Linearity Curve or Proto.io run on more platforms?
Linearity Curve runs on Mac, Ios. Proto.io runs on Web, iOS, Android.
Can I use Linearity Curve for free?
Yes. Linearity Curve has a free tier, so you can try it without paying. Proto.io starts at On request.
What is Linearity Curve best used for?
Linearity Curve is most often used for vector illustration, logo design, ui design, print design. Of those, vector illustration and logo design are not what Proto.io is typically brought in for.
What can Linearity Curve do that Proto.io cannot?
Linearity Curve covers Vector editing, Auto Trace, Typography tools, Pen tool. Proto.io covers Event and condition system, Timeline animation, Device preview, Component library.

Answered from the vendors’ own pages

Linearity Curve: Does Linearity Curve have a free plan?

Yes, Linearity offers a free Starter plan with 50 lifetime credits, 1 basic brand kit, and 5GB cloud storage. No credit card is required to access the free tier.

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.

Linearity Curve: Can I use Linearity Curve on multiple devices?

Yes, Linearity Curve is available on Mac, iPad, and iPhone, with real-time collaboration allowing teams to see changes instantly across devices.

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.

Linearity Curve: What file formats can I export from Linearity Curve?

Linearity Curve supports exporting to industry-standard formats including .ai, SVG, PDF, PNG, JPG, and TIFF, making it compatible with other design tools.

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.

Linearity Curve: Does Linearity Curve have AI-powered vectorization?

Yes, Linearity Curve includes an Auto Trace feature with three modes (Sketch, Photography, Illustration) that uses AI to instantly vectorize images into editable paths. It also includes AI-powered background removal.

Source
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