STL/3MF to STEP Converter — stltostep.app
Last updated: August 19, 2026
This tool converts 3D model files entirely inside your own browser. Your STL, 3MF, or ZIP file is never uploaded to any server — the conversion happens locally on your device, and the resulting STEP file never leaves your computer unless you choose to save or share it yourself. We do not collect, see, or store the files you convert.
This site is an independent, non-commercial project run by an individual developer. If you have any question about this policy or how your data is handled, you can write to [email protected].
All file parsing, smoothing, and STEP conversion runs as JavaScript and WebAssembly code inside your browser tab. No file you drag, select, or convert is ever sent over the network to us or to any third party. If you close the tab, the file and its converted result are gone — nothing is retained on our side because nothing ever reaches our side.
This site does not currently set any cookies and does not run any analytics or tracking script. It does not ask you to create an account and does not store any personal data about you.
We plan to support this free tool with advertising in the future. If and when ads are enabled, Google and its advertising partners may set cookies or use similar technologies in your browser to serve and measure ads, and — where required by law — to personalize them. Before that happens for visitors in the European Economic Area, the UK, or Switzerland, this site will show a consent request built on Google's certified consent management platform, so that no advertising cookie is set without your prior, informed choice. This policy will be updated at that point with details of the specific ad partners in use and links to their own privacy information.
This site is hosted on Cloudflare Pages. Like virtually any web host, Cloudflare's infrastructure processes standard technical information for every request it serves — such as your IP address, browser type, and the page requested — in order to deliver the site and protect it against abuse. This is standard server-log activity, not something this site configures or has access to itself. You can read Cloudflare's own privacy policy at cloudflare.com/privacypolicy.
If you are in the European Economic Area or the UK, data protection law gives you the right to access, correct, delete, or export any personal data held about you, and to object to or restrict its processing. Because this site does not collect or store personal data today, there is generally nothing to request — but if that changes (for example, once advertising cookies are introduced), those rights will apply to the data collected at that time, and you can exercise them by writing to [email protected]. You also have the right to lodge a complaint with your local data protection authority.
This policy may be updated as the site evolves — most notably when advertising is introduced. The "Last updated" date above will always reflect the latest version.