Credits and licences
This site is free partly because a lot of people gave their work away first. Here they are.
Everything below runs in your browser rather than on a server, which is the whole reason the tools here can be free with no account and no upload. None of it is ours.
The libraries
| Library | Licence | What it does here |
|---|---|---|
| UPNG.js Ivan Kutskir | MIT | PNG compression. It is the PNG engine inside Photopea, and it does palette quantisation properly, which is the difference between a 77% saving and a file that gets larger. |
| UTIF.js Ivan Kutskir | MIT | Reads TIFF files, which no browser can open on its own. |
| ag-psd Agamnentzar | MIT | Reads and writes Photoshop files with their layers, blend modes and masks intact. |
| Tesseract.js Project Naptha | Apache-2.0 | Recognises text in an image. Served from this site rather than a CDN, so a scanned passport never leaves the machine. |
| heic-to Hopper Gee, wrapping libheif | LGPL-3.0 | Opens the HEIC photographs an iPhone produces. Served unbundled at /vendor/heic-to/ so it can be replaced, which is what its licence asks for. |
| qrcode Ryan Day | MIT | Encodes QR codes, including the error correction and version selection. The escaping, the size arithmetic and the advice are ours; the encoding is his. |
| JsBarcode Johan Lindell | MIT | Draws EAN-13, UPC-A, Code 128, Code 39 and ITF-14 barcodes. The check digit arithmetic and the validation are ours. |
| pdf-lib Andrew Dillon | MIT | Builds and edits PDFs: merging, splitting, rotating, stamping. |
| pdf.js Mozilla | Apache-2.0 | Renders and reads existing PDFs. |
| jsPDF James Hall and contributors | MIT | Generates the documents: invoices, quotes, certificates, risk assessments. |
| qpdf (WebAssembly build) Jay Berkenbilt, compiled by jspawn | Apache-2.0 | Password protection and repair on PDFs. |
| jsdiff Kevin Decker | BSD-3-Clause | The Myers diff algorithm, which is what works out the shortest set of changes between two versions of a document. The word-level comparison and the invisible-character detection on top of it are ours. |
| marked Christopher Jeffrey and contributors | MIT | Turns markdown into HTML, following the CommonMark and GitHub specifications rather than guessing. |
| Turndown Dom Christie | MIT | The other direction: HTML back into markdown. |
| Astro The Astro team | MIT | Builds the site into static pages. |
| Svelte Rich Harris and contributors | MIT | Every tool on the site is a Svelte island. |
| Inter Rasmus Andersson | SIL Open Font License 1.1 | The typeface. |
A particular thank you
Three of the libraries above, UPNG.js, UTIF.js and the work behind them, are by Ivan Kutskir, who also built Photopea: a full image editor in a browser, on his own, since 2013, free to use.
He did not have to open source the pieces. He did, under the MIT licence, and this site's image tools are visibly better for it. If you need an image editor with more depth than ours, use his.
About the LGPL one
heic-to is licensed under the LGPL, which asks for something more than a credit: anybody using this site should be able to replace that library with their own build.
A normal build would make that impossible, because bundlers minify third-party code into the same files as ours. So it is not bundled. It is served whole and unmodified from /vendor/heic-to/heic-to.js, with its licence beside it, and swapping it means putting a different file at that path.
Our own code
The tools themselves, the calculators, the document engines and the writing are ours. The output belongs to you: there is no watermark, no attribution requirement and no restriction on what you do with anything this site produces, including commercially.
Getting this wrong
If something here is credited incorrectly, missing, or used in a way its licence does not allow, tell us and it gets fixed. Attribution is the price of the work and it should be right.