Open-source licences
This website, and the font engine that runs in your browser, are built with the open-source software and font below. Thank you to everyone who makes them.
Your rights under the LGPL
The engine uses GEOS, which is licensed under the GNU Lesser General Public License 2.1 and is copyright its contributors. GEOS is not part of our engine file: it is served unmodified as a separate file, libgeos.wasm, which the engine loads when it starts.
You may modify GEOS, build your own version (the complete source and our build steps are below), and use it with our engine in place of ours. You may also reverse engineer our engine as far as needed to debug such modifications. Nothing in our Terms of Use restricts these rights.
GEOS 3.13.1
Geometry library used by the stencil engine. Served unmodified as a separate file (libgeos.wasm) that the engine loads at run time.
GNU Lesser General Public License 2.1
LicenceComplete source codeHow it was built, and using your own build
Ryū (part of GEOS)
Number formatting inside GEOS.
Apache License 2.0 or Boost Software License 1.0
nlohmann/json (part of GEOS)
JSON support inside GEOS.
MIT
musl libc
C standard library compiled into the engine.
MIT
LLVM libc++, libc++abi, libunwind and compiler-rt
C++ runtime compiled into the engine.
Apache License 2.0 with LLVM Exceptions
Emscripten
Loader that starts the engine in the browser.
MIT / University of Illinois NCSA
fontTools
Parts of fontTools (its outline pens, CFF charstring reader and writer, and standard glyph-name tables) are translated into the engine's C++.
MIT
Adobe Glyph List For New Fonts, by Adobe
Standard names the engine gives to glyphs that don't have one.
BSD 3-Clause License
CPython (one maths routine)
The engine measures distances exactly as Python's math.hypot does, using a C++ translation of CPython's vector_norm.
Python Software Foundation License Version 2
Next.js, React, Vercel Web Analytics, SWC helpers
The website itself.
MIT (SWC helpers: Apache License 2.0)
Roboto Bold, by Google
The showcase uses the original font. The stencil lettering in the headings uses a modified copy: Roboto Bold with stencil bridges added by this site's engine, renamed “BMF Heading Stencil”.
Apache License 2.0