Fix Your 3D Mesh Files Instantly
Free browser-based STL repair tool. No uploads, no signups. Your files stay on your device.
Features
Auto-Repair
One-click fix for non-manifold geometry, flipped normals, holes, and degenerate triangles.
Mesh Analysis
Detailed geometry and topology analysis with issue detection.
100% Private
All processing happens locally in your browser. Files never leave your device.
Multiple Formats
Import STL, OBJ, OFF. Export to STL (binary/ASCII), OBJ, or OFF.
How It Works
Drop your STL file
Drag and drop or click to browse. Supports STL, OBJ, and OFF files.
Review analysis & issues
See detailed geometry, topology stats, and automatically detected issues.
Click Auto-Repair
One click fixes non-manifold geometry, flipped normals, holes, and more.
Download fixed mesh
Export your repaired mesh in STL, OBJ, or OFF format.
Explore
Frequently Asked Questions
How does this work without uploading my file?
JustFixSTL runs entirely in your browser using WebAssembly. Your mesh files are processed locally on your device and never leave your computer.
What file formats are supported?
STL, OBJ, and OFF files are supported. These are the most common formats used in 3D printing, CAD, and 3D modeling workflows.
What issues can JustFixSTL repair?
The tool can fix non-manifold edges and vertices, fill holes, remove degenerate triangles, weld duplicate vertices, fix flipped normals, and remove isolated vertices. These are the most common issues that cause 3D print failures.
Is there a file size limit?
The tool handles files up to 100 MB. Since everything runs in your browser, performance depends on your device — most desktop computers handle large meshes without issue.
Will repairing change my model's shape?
Repairs are designed to be as conservative as possible. Operations like fixing normals and removing degenerate faces don't change geometry at all. Hole filling adds minimal new faces to close gaps. You can preview changes in the 3D viewport before exporting.