Open-source credits
Thank you! usefulweb.site stands on the shoulders of open-source projects and open data. These are the programs, fonts and datasets we use, what we use them for and under which license.
Programs run unmodified as separate processes on our server; we do not distribute them. Bundled data is credited here and in the tool that uses it. License texts that must accompany copies are linked below.
Programs our tools run on the server
| Project | What we use it for | License | How we honor it |
|---|---|---|---|
| FFmpeg | Converting, trimming, compressing and inspecting audio and video files. | LGPL-2.1-or-later; our build is configured with --enable-gpl (GPL) | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| ImageMagick | Image conversion, resizing, watermarks and image inspection. | ImageMagick License | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| Ghostscript | PDF compression and PDF rendering. | AGPL-3.0-or-later | We only invoke the unmodified Ghostscript binary from Ubuntu as a separate process. We have not modified Ghostscript, so there are no modified sources to offer; the original sources are available from ghostscript.com and Ubuntu. |
| qpdf | Merging, splitting, rotating, encrypting and repairing PDFs. | Apache-2.0 Apache-2.0.txt | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| Poppler (pdftoppm, pdftotext, pdfinfo) | PDF to image, PDF text extraction and PDF metadata. | GPL-2.0-or-later | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| LibreOffice | Converting office documents (Word, Excel, PowerPoint, OpenDocument) to and from PDF. | MPL-2.0 MPL-2.0.txt | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| OCRmyPDF | Adding a searchable text layer to scanned PDFs. | MPL-2.0 MPL-2.0.txt | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| Tesseract OCR (with English and German language data) | Text recognition (OCR) in images and scans. | Apache-2.0 Apache-2.0.txt | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| ExifTool by Phil Harvey | Reading and removing photo and document metadata (EXIF, GPS, XMP). | Artistic License or GPL (same terms as Perl) | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| libwebp (cwebp, dwebp) | Encoding and decoding WebP images. | BSD-3-Clause | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| libavif (avifenc, avifdec) | Encoding and decoding AVIF images. | BSD-2-Clause | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| libheif and libde265 | Decoding HEIC/HEIF photos (e.g. from iPhones). | LGPL-3.0 (libheif, libde265); MIT (libheif example programs) | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| LibRaw (dcraw_emu) | Developing camera RAW photos. | LGPL-2.1 or CDDL-1.0 | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| img2pdf | Lossless images to PDF. | LGPL-3.0-or-later | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
Fonts used when rendering documents
| Project | What we use it for | License | How we honor it |
|---|---|---|---|
| DejaVu fonts | Fallback fonts when converting documents and rendering text in images. | Bitstream Vera Fonts License (changes: public domain) | Installed from Ubuntu, used unmodified by the converters. Credited here. |
| Liberation fonts 2 | Metric-compatible fonts for office document conversion. | SIL Open Font License 1.1 | Installed from Ubuntu, used unmodified by the converters. Credited here. |
| URW++ base 35 fonts | The standard PostScript fonts used by Ghostscript. | AGPL-3.0 with font exception | Installed from Ubuntu, used unmodified by Ghostscript. The font exception covers documents that embed the fonts. Credited here. |
Platform and hosting
| Project | What we use it for | License | How we honor it |
|---|---|---|---|
| Node.js | Runs the whole site: web server, tools, API and MCP server (no other runtime packages). | MIT (plus the licenses of its bundled dependencies) | Official unmodified release, run on our server. Credited here. |
| SQLite | Database (through node:sqlite). | Public domain | No obligations; credited with thanks. |
| nginx | TLS termination and reverse proxy. | BSD-2-Clause | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| Certbot and Let’s Encrypt | Free TLS certificates for every site. | Apache-2.0 (Certbot) Apache-2.0.txt | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| Postfix | Delivering feedback-form messages to the operator. | IBM Public License 1.0 or EPL-2.0 | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| OpenDKIM | Signing outgoing mail (DKIM). | BSD-3-Clause and Sendmail Open Source License | Unmodified Ubuntu package, started as a separate process on our server. We do not modify or distribute it. Credited here with a link to the project and its license. |
| Ubuntu and the Linux kernel | Server operating system (including nftables, ufw and fail2ban for security). | Various free licenses, mainly GPL-2.0 | Unmodified distribution packages. Credited here. |
Bundled data
| Project | What we use it for | License | How we honor it |
|---|---|---|---|
| Natural Earth | Country outlines for the geo charts (1:110m Admin 0 countries, pruned). | Public domain | No obligations; credited here, in data/geo/README.md and on every rendered map. |
| MDN browser-compat-data | Offline subset for the Browser Compatibility Checker. | CC0-1.0 | No obligations; credited here and in every result (with the data version). |
| web-features (W3C WebDX Community Group) | Baseline status in the Browser Compatibility Checker. | Apache-2.0 Apache-2.0.txt | A pruned, modified copy is bundled: we ship the Apache-2.0 text, state the changes (data/browser-compat/README.md) and credit the source. The project has no NOTICE file. |
| Google libaddressinput address metadata | Address formats per country (LocaleKit). | CC-BY-4.0 (data) CC-BY-4.0.txt | Attribution: © Google, CC BY 4.0, converted to a compact format (changes indicated). License linked and shipped. |
| Google libphonenumber metadata | Country calling codes, trunk prefixes and number lengths (LocaleKit). | Apache-2.0 Apache-2.0.txt | Derived data is bundled: we ship the Apache-2.0 text and state that the data was extracted and reduced from PhoneNumberMetadata.xml. The project has no NOTICE file. |
| World Bank World Development Indicators | Consumer price index series (Inflation Time Machine). | CC-BY-4.0 CC-BY-4.0.txt | Attribution: The World Bank, World Development Indicators (FP.CPI.TOTL), CC BY 4.0; credited here and on every result. |
| Nager.Date | Public holidays 2024–2030 (RuleDate and date tools). | MIT MIT-Nager.Date.txt | The MIT copyright and permission notice is shipped with the bundled data. |
| SPDX License List | License identifiers, names and OSI/FSF flags (SBOM License Checker). | SPDX License List terms (Linux Foundation) | Only identifiers, names and flags (facts) are bundled, with the list version; credited here and in the tool. |
| Can I use… (Alexis Deveria) | Browser support facts for file formats (FileFit). | CC-BY-4.0 CC-BY-4.0.txt | Attribution: © Alexis Deveria, caniuse.com, CC BY 4.0; facts transcribed (changes indicated). License linked and shipped. |
| Unicode Character Database | Character names for the Unicode Inspector (a small subset of UnicodeData.txt). | Unicode License v3 Unicode-3.0.txt | The Unicode copyright and permission notice is shipped with the data. |
| Mozilla Server Side TLS guidelines | Modern/intermediate/old TLS presets (TLS Cipher Suite Simulator). | MPL-2.0 MPL-2.0.txt | The preset values are bundled in source form under MPL-2.0: license text shipped, source linked here. |
| Qualys SSL Labs client list | Recorded TLS handshakes of real clients (TLS Cipher Suite Simulator). | SSL Labs terms of use | Retrieved once from the public API; source and retrieval date are shown with every result. |
| IANA TLS parameter registries | Cipher suite and group names and codes. | IANA licensing terms (registries are free to use) | Credited with the retrieval date. |
| FoodSafety.gov Cold Food Storage Chart | Fridge and freezer storage times (Food Storage Guide). | Public domain (U.S. federal government work) | No obligations; source credited on every result. |
| Ready.gov (FEMA) and BBK preparedness guides | Emergency kit quantities and quotes (Disaster Prep Builder). | Public domain (Ready.gov); short quotations with attribution (BBK) | Short quotations with source and retrieval date on every result. |
| InterNACHI Estimated Life Expectancy Chart | Typical service life of home components (How Long Will It Last). | © InterNACHI (facts quoted with attribution) | Only year ranges (facts) are quoted, with source and link on every result. |
| Official provider documentation (Google, GitHub, Microsoft, Slack, OpenID Foundation and service help centres) | OAuth scope descriptions and cancellation steps, condensed from the official pages. | Facts condensed from the providers’ public documentation | Every entry links its official source page; descriptions are condensed, not copied wholesale. |
Development tools
| Project | What we use it for | License | How we honor it |
|---|---|---|---|
| TypeScript | Type checking during development (Node.js runs the code without a build step). | Apache-2.0 Apache-2.0.txt | Development dependency only; not distributed. |
| @types/node (DefinitelyTyped) | Node.js type definitions for development. | MIT | Development dependency only; not distributed. |
Services (not open source)
Advertising, consent and statistics use Google AdSense, Google Privacy & Messaging and Google Analytics; tools that query live public APIs name their source on every result. These services are described in the privacy policy. Privacy
License texts shipped with bundled material
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