Frequently Asked Questions

Last updated: 2026-05-20

Answers to common questions about STLViewer — the free browser-based STL and 3MF viewer.

Is STLViewer free to use?

Yes. You can upload, preview, and share STL or 3MF models for free, with or without an account.

Do I need to create an account?

No. Anonymous uploads work out of the box and produce a share link you can send to anyone. An account is only needed to manage your model library, set thumbnails, or delete models later.

What file formats are supported?

STL (both binary and ASCII) and 3MF are supported. Only the mesh geometry is parsed — we do not read slicer metadata from 3MF.What is an STL file?What is a 3MF file?

Are my uploaded models private?

Yes. Only people with the share link can view your model. The share pages are explicitly excluded from our sitemap, and we send noindex directives to search engine crawlers, so shared models cannot be discovered by searching.

How large a file can I upload?

The limit is 20 MB per file and 50 MB total per session. Files that exceed the limit are rejected at the presign step before any bytes are uploaded.

Can I embed the viewer on my own site?

Yes. Open the Share dialog for any model and copy the ready-made <iframe> snippet, then paste it into your page — plain HTML, WordPress, Webflow, and Notion all work. URL parameters let you control rendering, materials, background, and more.How to embed a 3D modelEmbed options reference

Where are the files stored?

File blobs live on Cloudflare R2 (S3-compatible object storage). Metadata, accounts, and share-link state are stored in a Supabase Postgres database.

Can I store my models in my own cloud storage?

Yes. Registered users can connect their own Cloudflare R2 bucket, and new uploads are written there instead of our built-in storage. You keep control of the files, there's no bucket CORS to configure, and you can disconnect at any time without losing them.How to connect your own cloud storage

How do I delete a model?

Authenticated users can delete their own models from the dashboard. Deletion is queued and removes the file from storage asynchronously. Anonymous uploads expire on a schedule managed by the queue.

Is there a mobile app?

No native mobile app. STLViewer runs in any modern browser — Safari, Chrome, and Firefox on mobile all work.

How can I support the project?

A link to Buy Me a Coffee is in the footer. Reporting bugs on Discord or Telegram also helps a lot.

Does STLViewer track me or use analytics?

No optional analytics, marketing, or preference cookies are set. We use only technically necessary cookies (session state). No third-party tracking scripts are loaded. You can verify this in the cookie consent banner or by inspecting network requests.