About SB Tools
SB Tools — short for Simple Box — is a collection of free online tools for developers, documents, images and everyday calculations. Our motto: tools so simple, no brain required.
What we believe
- Your data is yours. Every tool runs locally in your web browser using JavaScript and WebAssembly. Files and text you work with are not uploaded to us.
- Simple beats clever. Each tool does one job, opens fast and explains itself. No accounts, no paywalls in the middle of a task, no watermarks.
- Quality over quantity. We would rather have 104 tools that work properly than thousands of thin pages. Every tool page explains what it does, how to use it and its limits, and a tool that we cannot make work well does not ship.
How the tools work
When you open a tool, your browser downloads the page and its code. From then on, the processing happens on your device. For example, the PDF tools use the open-source libraries pdf-lib and PDF.js, and the background remover runs a small neural network with ONNX Runtime for the web. Libraries are served from this site, not from third-party CDNs, and pages carry a strict Content Security Policy that only allows code from this site.
A few tools need extra downloads, always from this site: the HEIC converter loads a 1.3 MB decoder and the background remover loads a 16–24 MB AI model the first time you use them. No tool sends your input anywhere.
How we build and test tools
- Every tool is operated in a real Chrome browser at desktop and phone sizes with automated tests that feed it normal input, edge cases and malformed input, and check the exact output.
- Calculators are cross-checked against known reference values — for example, a $200,000 loan over 30 years at 6.5% must come out at $1,264.14 a month. Formulas and standards are named and linked where a result depends on them, for example RFC 9562 for UUIDs or the Mifflin–St Jeor equation for calories.
- Pages are checked for broken links, valid structured data, keyboard access, color contrast in light and dark themes, and console errors before each release.
- Found a wrong result? Tell us — we fix and re-test it.
Open-source credits
SB Tools builds on excellent open-source projects, including pdf-lib, PDF.js (Mozilla), JSZip, js-yaml, marked, CryptoJS, heic2any, qrcode-generator (Kazuhiko Arase), jsQR, sql-formatter, js-beautify, Turndown, ONNX Runtime Web, MODNet and U²-Net. Their licenses are included with the files in our /vendor/ folder. QR Code is a registered trademark of DENSO WAVE INCORPORATED.
Contact
Questions, bug reports or tool ideas are welcome: (the address appears when JavaScript is on). See also our contact page.