How Font Tools works

Most online font converters work by uploading your file to a server, processing it there, and sending back a result — which means your font, however proprietary or license-restricted, has to leave your device. Font Tools doesn't do that. Every tool on this site runs entirely inside your browser tab, using an open-source library called fonteditor-core compiled to WebAssembly.

Reading a font

When you drop a file, fonteditor-core parses its internal tables (glyph outlines, metrics, hinting instructions) directly from the bytes in your browser's memory. WOFF2 files are first decompressed using a dedicated WebAssembly codec, since WOFF2's compression isn't something plain JavaScript can efficiently decode.

Writing the result

Once parsed, the same glyph data is re-packaged into the target format's container — TTF, WOFF, or WOFF2. OTF is a special case: it can only be a starting format, not a result, because it stores glyphs as PostScript (CFF) curves rather than TrueType curves — that conversion happens automatically the moment an OTF file is read.

The live preview

Before or after converting, this tool loads your font directly with the browser's own FontFace API to render sample text in it — a separate, native code path from the conversion itself, so you can confirm you picked the right file.

What "never uploaded" actually means

Concretely: when you drop a font onto this site, it's read directly from your device into your browser's memory. No fetch, no form submission, no network request carries your font data anywhere. You can confirm this yourself using your browser's developer tools — open the Network tab while converting a file, and you'll see no outgoing request containing your font data.

For the full picture on what little data is collected (aggregate analytics, advertising cookies once ads are enabled), see our Privacy Policy.