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Developer Tools · head to head

PartyKit vs Principle

P

PartyKit

Developer Tools

Platform for building and deploying realtime multiplayer servers on the edge

From
Free
Free plan
Yes
Visit PartyKitFull review
P

Principle

Design

Animate your ideas, design better apps

From
$129/one-time
Free plan
No
Visit PrincipleFull review

The short version

  • PartyKit is free; Principle starts at $129 one-off.
  • Only PartyKit lists stateful edge servers; only Principle lists timeline-based animation.
  • Where PartyKit falls short: documentation and FAQ material on the marketing site is sparse compared to larger realtime platforms.
  • Where Principle falls short: macOS only with no Windows or Linux editor available.
  • Prices and features on this page were last checked on 30 August 2026.

Where they differ

Only the attributes on which PartyKit and Principle actually diverge.

Attributes where PartyKit and Principle differ
AttributePartyKitPrinciple
Starting priceFree$129/one-time
Free tierYesNo
PlatformsWeb, APImacOS
CategoryDeveloper ToolsDesign

Not yet recorded: pricing model for Principle, founded for PartyKit.

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 PartyKit

  • Stateful edge servers
  • WebSocket-first API
  • CRDT library compatibility
  • Framework integrations
  • Global edge deployment
  • Custom domains

Only in Principle

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

What people use each for

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

PartyKit

  • Multiplayer collaborative appsnot Principle
  • Realtime AI agent backendsnot Principle
  • Live cursors and presencenot Principle
  • Collaborative whiteboards and documentsnot Principle

Principle

  • Mobile app prototypesnot PartyKit
  • Micro-interactionsnot PartyKit
  • Animation designnot PartyKit
  • User flow designnot PartyKit
  • Gesture-based interfacesnot PartyKit

Where each one falls short

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

PartyKit

  • Documentation and FAQ material on the marketing site is sparse compared to larger realtime platforms
  • Commercial free tier requires deploying to the user's own Cloudflare account, adding setup complexity
  • Storage on the free Individual plan clears every 24 hours, limiting it to prototyping rather than persistent production data
  • Smaller ecosystem and community than more established realtime infrastructure providers

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

Pricing, plan by plan

PartyKit

Free
  • IndividualFree
    • Up to 10 live projects
    • Deploy to the global edge platform
    • Storage clears every 24 hours
  • CommercialFree
    • Unlimited projects
    • Custom domains
    • Runs on your own Cloudflare account; pay only Cloudflare usage

Principle

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

Which should you pick?

Choose PartyKit if

  • You need stateful edge servers.
  • You want to start without paying.
  • You work on Web, API.
  • You also want websocket-first api.
PartyKit review

Choose Principle if

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

Questions people ask

Is PartyKit or Principle better?
Neither clearly leads. PartyKit starts at Free and Principle at $129/one-time, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, PartyKit or Principle?
PartyKit has a free tier; the other does not. Paid plans start at Free for PartyKit and $129/one-time for Principle.
Does PartyKit or Principle run on more platforms?
PartyKit runs on Web, API. Principle runs on macOS.
Can I use PartyKit for free?
Yes. PartyKit has a free tier, so you can try it without paying. Principle starts at $129/one-time.
What is PartyKit best used for?
PartyKit is most often used for multiplayer collaborative apps, realtime ai agent backends, live cursors and presence, collaborative whiteboards and documents. Of those, multiplayer collaborative apps and realtime ai agent backends are not what Principle is typically brought in for.
What can PartyKit do that Principle cannot?
PartyKit covers Stateful edge servers, WebSocket-first API, CRDT library compatibility, Framework integrations. Principle covers Timeline-based animation, Interactive prototypes, Touch gestures, Component reuse.

Answered from the vendors’ own pages

PartyKit: How much does PartyKit cost?

PartyKit is completely free. Both the Individual and Commercial plans have no upfront costs.

Source
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
PartyKit: What is PartyKit's Individual plan?

The Individual plan is free and includes deployment to a global edge platform, support for up to 10 live projects, and is suitable for small projects. Storage is cleared every 24 hours.

Source
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
PartyKit: What is PartyKit's Commercial plan?

The Commercial plan is free but requires deploying to your own Cloudflare account. It includes custom domains, unlimited projects, and you pay only your Cloudflare usage costs.

Source
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
PartyKit: Can I upgrade from Individual to Commercial plan?

Yes, both plans are free but offer different feature sets. The Commercial plan removes project restrictions but requires managing your own Cloudflare infrastructure.

Source
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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