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CAD · head to head

SolveSpace vs Zoo

S

SolveSpace

CAD

Open source parametric CAD with a constraint solver in a few megabytes

From
Free
Rated
-
Full reviewWebsite
Zoo logo

Zoo

CAD

Cloud CAD with a scripting language and a geometry engine exposed as an API

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: SolveSpace the in-house geometry kernel fails on complex boolean operations and fillets, and the failure is sometimes silent bad geometry rather than an error message, so models must be checked before export or manufacture.; Zoo the geometry engine runs entirely in Zoo's cloud and there is no offline mode, so an aircraft, a customer site with no guest wifi or an outage stops modelling work completely.
  • They diverge on capability: SolveSpace covers Constraint solver, Zoo covers KCL scripting.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which SolveSpace and Zoo actually diverge.

Attributes where SolveSpace and Zoo differ
AttributeSolveSpaceZoo
Pricing modelOpen source, no licence feePer user per month
PlatformsWindows, macOS, LinuxWeb, Windows, macOS, Linux, API

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (CAD).

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 SolveSpace

  • Constraint solver
  • Solid modelling
  • Assemblies
  • Export formats
  • Cross-platform
  • Small footprint

Only in Zoo

  • KCL scripting
  • Design Studio
  • Design API
  • Zookeeper agent
  • Format conversion
  • Open source client

What people use each for

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

SolveSpace

  • Designing 3D printed parts on a machine that cannot run mainstream CADnot Zoo
  • Teaching constraint-based parametric modelling without buying licences for a classroomnot Zoo
  • Checking that a mechanical linkage moves as intended before cutting metalnot Zoo
  • Producing dimensionally accurate STEP or STL output from a small open source toolchainnot Zoo

Zoo

  • A hardware startup that wants part models reviewed in pull requests alongside firmwarenot SolveSpace
  • A software team generating thousands of parametric part variants programmatically rather than by handnot SolveSpace
  • A SaaS product that needs to render and convert customer CAD files without licensing a geometry kernelnot SolveSpace
  • An engineer who models occasional brackets and enclosures and does not want a four figure annual seatnot SolveSpace

Where each one falls short

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

SolveSpace

  • The in-house geometry kernel fails on complex boolean operations and fillets, and the failure is sometimes silent bad geometry rather than an error message, so models must be checked before export or manufacture.
  • There is no proper drawing and dimensioning workflow, so manufacturing documentation has to be produced in another application.
  • Development is volunteer-led and intermittent; long gaps between releases are normal and there is no support contract available at any price.
  • Assembly-level import of external CAD is very limited, so it does not fit a supply chain that exchanges native or assembly-level models with suppliers.
  • The interface follows its own conventions rather than mainstream CAD ones, so existing SolidWorks or Fusion users spend time unlearning habits for a tool with a lower ceiling.

Zoo

  • The geometry engine runs entirely in Zoo's cloud and there is no offline mode, so an aircraft, a customer site with no guest wifi or an outage stops modelling work completely.
  • STEP and SLDPRT import are still labelled experimental, which means the most common way of receiving a supplier or customer model is the least reliable path into the tool.
  • Drawing production, GD&T and tolerance annotation are far behind SolidWorks, Creo and NX, so most users still need a second package to release a manufacturing drawing.
  • Zookeeper is billed in reasoning minutes rather than per seat, so a team cannot forecast next month's bill from headcount the way it can with conventional CAD subscriptions.
  • The open source label applies only to the Design Studio client; the kernel that does the modelling is closed and hosted, so forking the repository does not give you a product you can run yourself.

Pricing, plan by plan

SolveSpace

Free
  • SolveSpaceFree
    • Full application under the GPL
    • No seat limit
    • Windows, macOS and Linux builds

Zoo

Free
  • FreeFree
    • Design Studio access
    • About 20 minutes of Zookeeper reasoning per month
    • Around $10 of API calls included
  • Plus$20/month
    • Roughly 400 Zookeeper minutes per month
    • Pay as you go beyond the allowance
    • Design Studio and API access
  • Pro$99/month
    • Unlimited Zookeeper reasoning
    • Higher API allowance
    • Priority support

Which should you pick?

Choose SolveSpace if

  • You need constraint solver.
  • You want to start without paying.
  • You work on Windows, macOS, Linux.
  • You also want solid modelling.
SolveSpace review

Choose Zoo if

  • You need kcl scripting.
  • You want to start without paying.
  • You work on Web, Windows, macOS, Linux, API.
  • You also want design studio.
Zoo review

Questions people ask

Is SolveSpace or Zoo better?
Neither clearly leads. SolveSpace starts at Free and Zoo at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, SolveSpace or Zoo?
SolveSpace starts at Free and Zoo at Free.
Does SolveSpace or Zoo run on more platforms?
SolveSpace runs on Windows, macOS, Linux. Zoo runs on Web, Windows, macOS, Linux, API.
Can I use SolveSpace for free?
Both have a free tier, so you can try either at no cost before committing.
What is SolveSpace best used for?
SolveSpace is most often used for designing 3d printed parts on a machine that cannot run mainstream cad, teaching constraint-based parametric modelling without buying licences for a classroom, checking that a mechanical linkage moves as intended before cutting metal, producing dimensionally accurate step or stl output from a small open source toolchain. Of those, designing 3d printed parts on a machine that cannot run mainstream cad and teaching constraint-based parametric modelling without buying licences for a classroom are not what Zoo is typically brought in for.
What can SolveSpace do that Zoo cannot?
SolveSpace covers Constraint solver, Solid modelling, Assemblies, Export formats. Zoo covers KCL scripting, Design Studio, Design API, Zookeeper agent.

Answered from the vendors’ own pages

SolveSpace: Is it really free for commercial work?

Yes. It is released under the GPL with no licence fee and no seat limit. Support is community only.

Zoo: Is Zoo the same company as KittyCAD?

Yes. KittyCAD renamed itself Zoo; the GitHub organisation is still KittyCAD and the scripting language KCL keeps the old initials.

SolveSpace: Can it replace Fusion 360 or SolidWorks?

No. It handles parts and simple assemblies well. Complex geometry, drawings and supply chain interoperability are outside its range.

Zoo: Can I use Zoo without an internet connection?

No. The geometry engine is a cloud service, so Design Studio needs a live connection to model anything.

SolveSpace: What hardware does it need?

Very little. It runs on old laptops and small Linux machines where mainstream CAD will not start.

Zoo: Is Design Studio free?

There is a genuine free tier with a small monthly allowance of AI reasoning and API calls. Paid plans start at $20 per month.

Zoo: Can I replace SolidWorks with Zoo?

Not for drawing release, large assemblies or GD&T. Teams typically use Zoo for programmatic part generation and keep an established package for production documentation.

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