Edit STL files online — free, in your browser

What you can do with an STL here

• Resize and transform — scale a model to fit your printer or fix a part exported in the wrong units, then move and rotate with numeric inputs, not just a mouse drag.
• Cut and combine — boolean subtract, union, and intersect against boxes, cylinders, and six other parametric primitives. Chop a model in half for a bigger-than-bed print, cut a hole where you need one, or merge two models into a single STL.
• Repair on import — duplicate vertices are welded automatically and degenerate triangles filtered out, then you get a watertight check with an exact open-edge count before you ever hit export.
• Check printability — volume and surface area are computed by the kernel, and an AI manufacturability review can flag thin walls, steep overhangs, and sharp internal corners before you slice (free during the alpha).
• Export a clean STL — binary STL out, with a warning first if the mesh isn't watertight. OBJ works in both directions too. Geometry export is free and not feature-gated.

How to edit an STL file online

1. Drop your .stl (or .obj) above — or open the editor and import from the File menu.
2. Make your edits — scale, move, rotate; cut and merge with booleans; add parametric shapes alongside the imported mesh.
3. Export — download the edited STL, or share a link so someone else can view it and suggest changes without installing anything either.

Why edit STL in the browser at all?

The tool most "free STL editor" roundups still recommend — Autodesk Meshmixer — was discontinued in 2021 and hasn't seen an update since. The desktop alternatives are either heavyweight (Blender, FreeCAD) or trial-limited. A browser editor sidesteps the whole problem: nothing to install, the same tool on Windows, macOS, Linux, and Chromebooks, and you're always on the current version.

Browser-based doesn't mean cloud-processed, though. Cadre's geometry kernel is written in Rust and compiled to WebAssembly, so importing, editing, and exporting all happen locally in your tab. Saving to the cloud and sharing are opt-in — if all you do is edit and re-export, your model never leaves your machine. For a deeper look at when browser CAD is (and isn't) enough, see when browser-based CAD is enough for 3D printing.

What this editor is good at — and what it isn't

Honest scoping, because nothing wastes your time like the wrong tool: Cadre is built for print-prep edits — resizing, splitting, combining, adding mounting bosses or cutouts, and sanity-checking printability. An imported STL is a triangle mesh, so you won't get a parametric feature history on it, and there are no sculpting brushes — for organic sculpting or scan retopology, Blender is still the right answer. Very large scan meshes (hundreds of MB) are limited by browser memory; typical print models import fine.

If you're designing a part from scratch rather than editing an existing file, the design rules that prevent failed prints are a better starting point — Cadre's parametric primitives and feature tools cover that workflow too.

FAQ

Is it actually free?

Yes. Importing, editing, and exporting STL/OBJ files is free and not trial-gated. The AI manufacturability review is also free during the current alpha.

Do I need an account?

No. The editor works without signing in. An account (email magic link — no password) is only needed if you want to save a project to the cloud or share an editable link.

Does my STL get uploaded somewhere?

No. The geometry kernel runs in your browser via WebAssembly — your file is processed locally. Cloud saving and share links are explicit, opt-in actions.

Can I edit OBJ files too?

Yes — OBJ import and export work the same way as STL.

Is there a file size limit?

No hard cap; the practical limit is your browser's memory. Models in the tens of megabytes work fine. This page is aimed at print-prep, not heavy scan cleanup — a 300 MB scan will be slow anywhere, including here.

Can someone help me edit my file?

Yes — share a link and collaborators can view the model and suggest changes from their browser, no install or account needed on their end either.