Parametric CAD for 3D printing, in your browser. Free and open source, try it now at: extrudo.org

Sketch a profile, pull it into a solid, round the edges, and change one number to watch the whole part follow. Extrudo is built for people who print: brackets, boxes, clips, enclosures and the replacement part you need by tonight. It runs in a browser tab, works offline once it has loaded, keeps your designs on your own machine and needs no account. Under the friendly interface sits exact geometry (real circles and fillets, not a mesh of triangles), so what you design is what comes out of the printer.

It follows the workflow people know from desktop CAD (sketch, features, timeline, parameters everywhere) with a faster, friendlier interface. It is inspired by that workflow and shares no code or artwork with any such product.

Light	Dark
Home: Start a design, open a template or import one
Modeling: A wall bracket with its browser, toolbar and timeline
Sketching: A dimensioned 2D sketch, top down, with its constraints
Sketch on a model: Editing the bracket's profile sketch in place
Feature dialogs: A fillet with its radius set by expressions and a live preview
Assemblies: A hinge, two components joined by a revolute joint
3D printing: Print Info: weight, filament and cost for the chosen material
Customizer: Sliders for a template's main parameters

Status: the stable app is the latest release. The core modeling workflow is there and tested, but expect rough edges. Things not built yet are listed in docs/03-roadmap.md. Please report what breaks.

https://app.extrudo.org: nothing to install; add it to your home screen or desktop from the browser's menu if you want it as an app. The newest features arrive first at https://edge.extrudo.org, the latest build of main (it can break). https://extrudo.org has an introduction and a short video.

To run it yourself, docker run -d -p 8080:80 ghcr.io/zoltanf/extrudo serves the app on http://localhost:8080 (docs/deploy.md, "Self-hosting with Docker").

Sketching. Lines, rectangles, circles, arcs, polygons, slots, ellipses and splines, with automatic constraints, 13 constraint types and driving dimensions. A sketch shows how much freedom is left in it, and refuses contradictions with a plain explanation. Trim, extend, fillet, offset, mirror, pattern and project from other geometry; export a sketch as SVG or DXF. Control-point splines and conics, text in the bundled fonts or your own, and SVG or DXF drawings imported into a sketch.

Solids. Extrude (with taper, symmetric, to an object, join, cut), revolve, box, cylinder, sphere and torus, fillet and chamfer with a diagnosis when a size does not fit, shell, holes (counterbore, countersink, M2 to M8 presets, heat-set inserts), combine, move and copy, mirror, rectangular, circular and path patterns, split body, scale, draft, press/pull and offset face. Sweep, loft and coil, modeled threads (ISO metric, UNC, UNF) that fit the hole or shaft they are put on, emboss and deboss onto flat and round faces, ribs, variable-radius fillets, up to 32 fillet and chamfer sets with in-view handles, and patterns that skip single instances.

Assemblies. Components gather bodies into the parts of an assembly, in the same design and timeline. Rigid, revolute and slider joints connect the parts: pose a joint in the view and check its clearance over its whole range, for a print-in-place hinge. 3MF and STEP exports keep each component together.

Import. STEP files as solid bodies; STL, 3MF and OBJ meshes as bodies you can still cut, join, move and split; pictures on a plane to trace over. OpenSCAD files (.scad), compiled in the browser, whose customizer variables can follow your design's parameters. .f3d designs open as editable designs: parameters, sketches, extrudes, holes, fillets, patterns and more, with the file's own body where a feature can't be rebuilt.

Construction geometry. Offset, angled, mid and three-point planes, tangent planes, axes through points, cylinders or edges, and points.

Parameters and the timeline. Every number takes an expression with units (wall * 1.5 + 2 mm) and named parameters. The design is an ordered timeline: roll back, edit, reorder, suppress, and fix references when something it pointed at is gone. Faces and edges keep their names through edits (topological naming), so changing an early feature rarely breaks a later one. A customizer with sliders and named configurations, and timeline groups.

For printing. Export STL, 3MF (with colours), STEP and OpenSCAD code; checked for watertightness. Place on Bed, overhang analysis, weight and filament length for your material, and section analysis. Measure distances, angles, areas and volumes exactly. One print tolerance that hole presets and threads follow, and a print estimate with walls, infill and cost.

Everywhere else. Version history with restore, a command palette (Ctrl+K), a right-click marking menu, light and dark themes, a built-in tutorial and templates, undo that covers everything, offline use, and an open file format. A folder on your disk linked to your designs, in browsers that allow it (Chrome, Edge).

From code. @extrudo/api builds and changes a design from TypeScript — a sketch, a solid, a parameter, a reference to a face — with the same commands the app uses, so a script and a person end up with the same design. Pure TypeScript: no DOM, no WASM. It runs in Node, in a worker and in the browser; the reference is published at extrudo.org/docs/api/.

Scripts. A TypeScript or JavaScript program in one timeline feature, with a CodeMirror editor, parameter completion, inline errors and console output. Programs run in a bounded QuickJS sandbox inside the geometry worker; the bodies they make are ordinary bodies you can fillet, measure and export. See the script guide. Record Macro turns what you make by hand into the same kind of script, and Export Design as Script writes a whole design as TypeScript or OpenSCAD. On the desktop, agents such as Claude Code can work on the open design over MCP (docs/desktop.md).

You need Node 24 or newer and pnpm 12 (see pnpm.io). The two WASM builds (the OpenCascade geometry kernel and the sketch solver) are not in git: pnpm dev, pnpm build and pnpm check download the build that matches your checkout from this repository's releases, using the GitHub CLI (gh auth login once) or a plain download when the repository is public.

git clone https://github.com/zoltanf/extrudo.git
cd extrudo
pnpm install
pnpm dev          # the app at http://localhost:5173
pnpm check        # typecheck, lint, package boundaries and unit tests
pnpm e2e:install  # once: download Playwright's Chromium
pnpm e2e          # build, then the end-to-end tests

pnpm wasm fetches the WASM on its own. Building it yourself (Docker, about 15 minutes for OpenCascade) is described in packages/kernel/occt/README.md and packages/sketch/planegcs/README.md.

The same kernel, the same solver and the same document model run in Node, so a design can be recomputed and exported without a browser — for a batch of variants, a CI check or a make rule:

pnpm extrudo info   bracket.extrudo --json
pnpm extrudo export bracket.extrudo --format 3mf --param width=160mm
pnpm extrudo set    bracket.extrudo --config Large --out bracket-large.extrudo
pnpm extrudo check  bracket.extrudo      # exits 2 when a feature has an error

docs/cli.md has every command, option and exit code, and @extrudo/cli is the library behind it for anything a script wants to do itself.

TypeScript, React 19, Vite, three.js, Radix and Tailwind. The geometry kernel is OpenCascade compiled to WebAssembly and runs in a Web Worker, behind a small C++ facade of our own; sketches are solved by planegcs (FreeCAD's solver) in WASM. The design is plain JSON; geometry is always derived from it, never stored.

Start with docs/02-architecture.md, then the roadmap and the decision records.

Bug reports, ideas, models that break the kernel and pull requests are all welcome. Read CONTRIBUTING.md first, and please follow the Code of Conduct. Security problems go through GitHub's private reporting, see SECURITY.md.

Extrudo is free software under the GNU GPL v3.0 or later.

• packages/io and the file-format specification are under the MIT license, so any tool can read and write Extrudo files.
• The OpenCascade and planegcs WASM files are LGPL-2.1 components built from their own sources; NOTICE lists every third-party component, its license, and where the corresponding source is.
• The Extrudo name and logo are trademarks, not covered by the GPL. Forks are welcome under their own name and icon: see TRADEMARKS.md.