UtilSlateSearch toolsCtrl K

Open-source notices

UtilSlate is built with the help of open-source software. Thank you to everyone who works on these projects.

HEIC decoder

The HEIC to JPG and HEIC to PNG converters use libheif and libde265, compiled to WebAssembly by thelibheif-js project (version 1.23.2). They are licensed under theGNU Lesser General Public License, version 3.

The libraries are used unmodified and delivered as separate files (a JavaScript loader and a WebAssembly module in the site’s asset folder), so they can be inspected or replaced independently of the rest of the site.

TIFF, AVIF and JPEG XL

These formats need code browsers don’t have. Each library loads only on the tool page that uses it.

  • UTIF.js (version 3.1.0), © Photopea, MIT License, reads TIFF files in the TIFF converter, with pako (© Vitaly Puzrin and Andrei Tuputcyn, MIT License):source code
  • jSquash (@jsquash/avif 2.1.1, @jsquash/jxl 1.3.0 and @jsquash/webp 1.5.0), © Jamie Sinclair and the Squoosh authors, Apache License 2.0: WebAssembly builds of the codecs below.source code
  • libavif (© Joe Drago, BSD 2-Clause License) and libaom, the AV1 encoder (© Alliance for Open Media, BSD 2-Clause License and the AOMedia Patent License 1.0), in JPG to AVIF and PNG to AVIF:libavif source,libaom source
  • libjxl (© the JPEG XL Project Authors, BSD 3-Clause License with a patent grant), includingBrotli (MIT License) and Highway (Apache License 2.0), in the JPEG XL converter:source code
  • Full license texts and notices

PDF tools

  • pdf-lib (version 1.17.1), © Andrew Dillon, MIT License, with pako, UPNG and tslib bundled: source code,license texts
  • PDF.js (version 6.3.289), © Mozilla and contributors, Apache License 2.0:source code, license. Its image decoders (OpenJPEG, JBIG2, qcms) come with their own licenses in /pdfjs/wasm/. PDF to PDF/A also uses its tables of the glyph names in PDF’s standard text encodings.
  • qpdf 12.2, © Jay Berkenbilt and contributors, Apache License 2.0, compiled to WebAssembly by@neslinesli93/qpdf-wasm (version 0.3.0, ISC License) with zlib and libjpeg-turbo, in Protect PDF and Unlock PDF:qpdf source,build source
  • fontkit (@pdf-lib/fontkit 1.1.1), © Devon Govett, Andrew Dillon and contributors, MIT License, embeds fonts for text beyond Latin-1:source code
  • regenerator-runtime (version 0.13.11), © Meta Platforms, Inc. and affiliates, MIT License, which fontkit needs to shape Tamil and other Indian scripts:source code
  • jsPDF (version 4.2.1) and svg2pdf.js (version 2.8.1), © the jsPDF authors and yWorks GmbH, MIT License, in SVG to PDF:jsPDF source,svg2pdf.js source
  • office2pdf 0.8.0, © the office2pdf authors, Apache License 2.0, compiled to WebAssembly with theTypst typesetting engine (Apache License 2.0) and some 370 Rust crates under permissive licenses, and the fonts Typst and office2pdf carry (Libertinus Serif, New Computer Modern, DejaVu Sans Mono, Noto Sans and Serif, Selawik), in Word to PDF and PowerPoint to PDF:source code,all license texts and notices
  • PDF to Word, Excel and PowerPoint, PDF to PDF/A (with its sRGB colour profile, written from the published IEC 61966-2-1 values) and the EPUB to PDF typesetter are UtilSlate’s own code. PDF/A files are checked in our tests with veraPDF, which isn’t part of the site.
  • Full license texts and notices for the PDF tools

File tools

  • 7-Zip 24.09, © Igor Pavlov, compiled to WebAssembly by 7z-wasm (version 1.2.0), GNU LGPL 2.1 or later, with the unRAR license restriction for the RAR decoder (it may not be used to create RAR files). It opens RAR, 7z, encrypted ZIP and compressed TAR archives:7-Zip source code,build source,license and unRAR notice
  • woff2, © the WOFF2 Authors, with Brotli, © the Brotli Authors, both MIT License, compiled to WebAssembly by wawoff2 (version 2.0.1, MIT License), in the Font Converter and Font Viewer:woff2 source,build source,license texts
  • The EPUB Reader cleans book pages with DOMPurify and the Font Viewer reads fonts with fontkit, both listed on this page.

Audio, video and GIF

  • Mediabunny (version 1.60.0), © Vanilagy and contributors, Mozilla Public License 2.0, reads and writes audio and video files and drives the browser’s own codecs:source code
  • Its extensions (MPL 2.0) bring codecs browsers lack: LAME 3.100 for MP3 (© the LAME project, GNU LGPL 2 or later;lame.sourceforge.io), FFmpeg’s AAC and AC-3 coders (© the FFmpeg developers, GNU LGPL 2.1 or later, built without GPL parts; ffmpeg.org) andlibFLAC (© the Xiph.Org Foundation, BSD 3-Clause License). Each runs as a separate file:extension sources
  • Full license texts, source links and the one build-time change
  • gifenc (version 1.0.3), © Matt DesLauriers, MIT License: its colour quantizer chooses GIF palettes (based on PnnQuant, © Mark Tyler, Dmitry Groshev and Miller Cy Chan).source code
  • libwebp (© Google, BSD 3-Clause License), through @jsquash/webp above, writes animated WebP frames where the browser can’t (lossless WebP, and Safari): source code
  • Resampling, time stretching, loudness and tempo analysis, the AVI reader, and the GIF, APNG and animated WebP readers and writers are UtilSlate’s own code.

On-device AI

The AI tools run open models in your browser. Each model downloads from this site the first time it’s used and stays in your browser; nothing you add is sent anywhere.

  • Transformers.js (version 4.3.0), © Hugging Face, Apache License 2.0, andONNX Runtime Web, © Microsoft Corporation, MIT License, run the models on the graphics card or the processor:Transformers.js source,ONNX Runtime source
  • Tesseract.js (version 7.0.0) and Tesseract, with Tesseract’s language files and GlyphLessFont, Apache License 2.0, read text in Image to Text and OCR PDF:Tesseract.js source,Tesseract source
  • Models: YuNet (© Shiqi Yu, MIT) for Blur Faces; ormbg (Apache 2.0) and BiRefNet lite(© ZhengPeng, MIT) for Background Remover; MI-GAN (© Picsart AI Research, MIT) for Object Remover;Real-ESRGAN (© Xintao Wang, BSD 3-Clause) for Image Upscaler; and SCUNet (Apache 2.0) for Image Denoiser. Real-ESRGAN and SCUNet were converted for the browser from their official releases.
  • Speech and music: Whisper (© OpenAI, MIT) for Transcribe Audio, Subtitle Generator and Speech to Text;Kokoro (© hexgrad, Apache 2.0), with misaki’s pronunciation dictionaries (Apache 2.0), for Text to Speech; and, for Remove Vocals, UVR-MDX-NET Inst HQ 5 fromUltimate Vocal Remover (© Anjok07 and the UVR developers, MIT) and Spleeter (© Deezer, MIT), in the form the sherpa-onnx project publishes (Apache 2.0).
  • Language: Opus-MT (© University of Helsinki, Apache 2.0 or CC BY 4.0 per model) for the Translator in browsers without their own; Florence-2 (© Microsoft, MIT) for Image Caption Generator. The Text Summarizer, Paraphrasing Tool and Tone Changer use the AI built into Chrome, which this site doesn’t distribute.
  • Full license texts, where each model comes from, and the one change to Tesseract.js

Barcodes

  • zxing-wasm (version 3.1.4), © Ze-Zheng Wu, MIT License, built from zxing-cpp(© the ZXing authors, Apache License 2.0) and zint (© Robin Stuart and contributors, BSD 3-Clause License). It reads barcodes in the barcode scanner and writes Data Matrix, PDF417 and Aztec codes:zxing-wasm source,zxing-cpp source,license texts
  • EAN, UPC, Code 128, Code 39 and ITF-14 barcodes are encoded by UtilSlate’s own code.

Code, writing and drawing tools

  • Prettier (version 3.9.9), © James Long and contributors, MIT License, formats HTML, CSS and JavaScript: source code
  • Terser (version 5.51.2), © Mihai Bazon and contributors, BSD 2-Clause License, minifies JavaScript: source code
  • sql-formatter (version 15.9.0), © the sql-formatter contributors, MIT License: source code
  • Harper (harper.js 2.10.0), © Automattic and contributors, Apache License 2.0, checks grammar and spelling: source code
  • imagetracerjs (version 1.2.6), by András Jankovics, released into the public domain (The Unlicense), traces images in PNG to SVG: source code
  • Full license texts and notices

QR codes

“QR Code” is a registered trademark of DENSO WAVE INCORPORATED.

Text and developer tools

  • yaml (version 2.9.1), © Eemeli Aro, ISC License: source code
  • marked (version 18.0.14), © MarkedJS and Christopher Jeffrey, MIT License, with parts of John Gruber’s Markdown (BSD License): source code
  • DOMPurify (version 3.4.16), © Cure53 and contributors, used under the Apache License 2.0: source code
  • Turndown (version 7.2.4), © Dom Christie, MIT License: source code
  • cRonstrue (version 3.27.0), © Brady Holt, MIT License: source code
  • Bowser (version 2.14.1), © Dustin Diaz and contributors, MIT License: source code
  • zxcvbn-ts (core and the common and English language packages), © the zxcvbn-ts authors and Dropbox, MIT License:source code. Its English common-words list is derived from OpenSubtitles 2024 via OPUS (Helsinki-NLP), under the Open Data Commons Attribution License.
  • Full license texts and notices

Data

  • Exchange rates: euro foreign exchange reference rates, source: European Central Bank. Published for information; the ECB does not use them for transactions. Rates for currencies the ECB doesn’t publish: Bank Negara Malaysia’s Open API, source: Bank Negara Malaysia.
  • Ingredient weights in the cooking converter: US Department of Agriculture, Agricultural Research Service,FoodData Central (SR Legacy), a public-domain US government work.
  • Time zones: the IANA time zone database, as built into your browser.
  • DOI lookups in the citation generator: Crossref’s public REST API. Crossref makes its bibliographic metadata available without restriction (CC0).
  • ISBN lookups in the citation generator: Open Library’s Books API, by the Internet Archive. Open Library’s catalog data is released into the public domain (CC0). Books it doesn’t have are looked up with the Google Books API, under Google’s APIs Terms of Service; the page names Google Books when it answered.
  • Passport and visa photo sizes: the issuing authorities’ published rules, each linked in the Passport Photo Maker.
  • Shoe sizes: the definitions of the UK, US, EU and Mondopoint systems, checked against the ISO/TS 19407 conversion.
  • Story and Reel safe zones in Crop Image: Meta’s published guidance for Stories and Reels.
  • Network tools: registration data from the registries’ RDAP services, found throughIANA’s RDAP bootstrap files; networks (AS numbers) fromTeam Cymru’s IP-to-ASN mapping; DNS answers from public resolvers (Cloudflare, Google, OpenDNS, AdGuard, Control D, NextDNS, AliDNS, DNS.SB and Wikimedia DNS).
  • Trusted roots in the SSL Checker: Mozilla’s list of root certificates trusted for websites (from NSS’s certdata.txt, Mozilla Public License 2.0), as extracted by curl(the 25 September 2026 copy): the subjects and keys used.

Network tools

  • @cloudflare/speedtest (version 1.14.1), © Cloudflare, MIT License, runs the Internet Speed Test against Cloudflare’s servers:source,license text
  • DNS, RDAP, TLS and port checks are UtilSlate’s own code, running on Cloudflare Pages Functions.

Fonts

  • Inter, © The Inter Project Authors, SIL Open Font License 1.1:source, license
  • Liberation Sans, Serif and Mono 2.1.5, © Google (digitized data, with Reserved Font Arimo, Tinos and Cousine) and Red Hat (with Reserved Font Name Liberation), SIL Open Font License 1.1, embedded by PDF to PDF/A and EPUB to PDF, and standing in for Arial, Times New Roman and Courier New in Word and PowerPoint to PDF:source,license
  • Carlito, © The Carlito Project Authors (with Reserved Font Name Carlito), and Caladea, © The Caladea Project Authors, SIL Open Font License 1.1, stand in for Calibri and Cambria in Word and PowerPoint to PDF:Carlito source,Caladea source,Carlito license, Caladea license
  • Noto Sans Tamil, © The Noto Project Authors, SIL Open Font License 1.1, embedded for Tamil text by the PDF tools that write text:source, license
  • Noto Sans SC, © Adobe (with Reserved Font Name “Source”), SIL Open Font License 1.1, embedded for Chinese text by the PDF tools that write text, as a Regular-weight subset of GB2312 and frequent Big5 characters made by tools/fonts/cjk-pdf-font.mjs:source, license
  • Plus Jakarta Sans, © The Plus Jakarta Sans Project Authors, SIL Open Font License 1.1:source,license

Icons

Interface icons are adapted from Lucide, ISC License.License text.

Site framework

Pages are generated with Astro (MIT License).

Trademarks

Microsoft, Word, Excel and PowerPoint are trademarks of the Microsoft group of companies. Chrome and Gemini are trademarks of Google LLC. Cloudflare is a trademark of Cloudflare, Inc. Other product names belong to their owners. They are used here only to say which files and browsers a tool works with; UtilSlate isn’t affiliated with, endorsed or sponsored by any of them.