Open-Source Licenses & Data Sources
KESI Tools is built on excellent open-source software and public data. Thank you to all of their authors and publishers.
Last updated: 2026-10-03
| Software | License | Used for |
|---|---|---|
| Astro | MIT | Website framework |
| React | MIT | Interactive UI |
| heic-to | LGPL-3.0 | HEIC photo decoding (includes libheif and libde265) |
| opencc-js | MIT, Apache-2.0 | Chinese script conversion |
| lunar-javascript | MIT | Lunar calendar, solar terms and almanac |
| node-qrcode | MIT | QR code generation |
| fflate | MIT | ZIP downloads |
| exifr | MIT | Reading photo EXIF data |
| UPNG.js | MIT | PNG color-reduction compression |
| pako | MIT, Zlib | PNG compression algorithm |
| pdf-lib | MIT | Merging, splitting, editing and signing PDFs |
| PDF.js | Apache-2.0 | PDF previews and PDF to images |
| Mediabunny | MPL-2.0 | Reading, converting and encoding video and audio |
| @mediabunny/mp3-encoder (LAME) | MPL-2.0, LGPL-2.0+ | MP3 encoding (LAME) |
| @mediabunny/aac-encoder (FFmpeg) | MPL-2.0, LGPL-2.1+ | AAC encoding (FFmpeg) |
| gifenc | MIT | GIF encoding |
| Lucide | ISC | Icons |
About the LGPL components
heic-to and the libheif and libde265 libraries it contains are licensed under the GNU LGPL 3.0. We use them unmodified and load them as a separate file. Source code is available from the heic-to project, and the full license text is at GNU LGPL v3.
The LAME MP3 encoder (GNU LGPL 2.0 or later) and FFmpeg’s AAC encoder (GNU LGPL 2.1 or later) are included as WebAssembly builds in @mediabunny/mp3-encoder and @mediabunny/aac-encoder. We use them unmodified and load them as separate files only when your browser lacks a built-in encoder. Source code is available from the Mediabunny project, LAME and FFmpeg.
About the MPL 2.0 components
Mediabunny and its encoder extensions are licensed under the Mozilla Public License 2.0. We use them unmodified. Source code is available from the Mediabunny project, and the full license text is at MPL 2.0.
Public data sources
- Taiwan public holidays and make-up workdays: “Government Office Calendar of the Republic of China” by the Directorate-General of Personnel Administration, Executive Yuan, from the Government Open Data Platform, used under the Open Government Data License, version 1.0.
- Lunar date verification: Hong Kong Observatory open data, Gregorian–Lunar Calendar Conversion (source: Hong Kong Observatory), details.
- Chinese conversion dictionaries: the OpenCC project, Apache 2.0 license.