📖 About

About Benri.dev

Thanks for stopping by Benri.dev.

What Benri.dev is

Benri.dev is a free collection of web tools for the small jobs that come up every day — counting characters, formatting JSON, making a QR code, splitting a bill. No app to install, no account to create; everything works right in your browser. Benri-bako — our little toolbox mascot and the site's Japanese name — is along for the ride.

The project began with a design goal: let people process text, code, images, and PDFs on their own device instead of sending each input to a different online service. We publish examples, instructions, assumptions, and limitations as readable static HTML rather than offering a bare collection of controls.

Three promises

  • Free: every tool is free. Ads may be shown, but there is no usage fee.
  • Privacy first: every tool runs in your browser. What you type is never sent to or stored on our servers.
  • Fast & light: no bloat, quick to load, smooth on mobile.

Advertising

This site is being reviewed for Google AdSense. During review, the AdSense delivery script and ad spaces are disabled, so no Google ads are displayed. If advertising is enabled later, pages without substantive content, navigation-focused pages, and error pages will remain outside the delivery scope. We use Google Analytics for traffic measurement; see our Privacy Policy for details.

Who runs it

Development and verification

  • On-device processing: tool inputs, images, PDFs, and generated secrets are not sent to Benri.dev's servers for processing.
  • Static explanations: instructions, examples, limitations, and FAQs are included in the page HTML rather than generated later by JavaScript.
  • Japanese/English parity: both language versions provide the same functionality and are checked before release.
  • Automated checks: we test syntax, metadata, links, visible FAQ/JSON-LD consistency, and representative tool input/output behavior.
  • Visible limitations: estimates, unsupported formats, year ranges, and rules that can change over time are documented rather than hidden.

Sources, updates, and corrections

For laws, taxes, holidays, health reference standards, and technical specifications, we prioritize primary material from public agencies, standards bodies, and official documentation. Time-sensitive data includes a review date or supported range. If we cannot maintain a changing rule responsibly, we consider reducing or retiring that feature.

If you find an error, outdated statement, or malfunction, use the Contact page and include the URL, environment, and expected result. We review the report, make necessary corrections, and rerun the relevant checks.

Trademarks

Company, service and product names mentioned on this site (Mercari, X (formerly Twitter), Google, YouTube and others) are trademarks or registered trademarks of their respective owners. "QR Code" is a registered trademark of DENSO WAVE INCORPORATED. They are used only to describe features related to those services. This site is not affiliated with, sponsored by or endorsed by any of these companies.

Open-source software

The QR code tools bundle node-qrcode (MIT License, Copyright (c) 2012 Ryan Day) together with its dependency dijkstrajs (MIT License, Copyright (C) 2008 Wyatt Baldwin). The full license text is included in the distributed file /assets/js/qrcode.min.aa5d988c.js.

The PDF tools (Merge PDF, Split PDF, Images to PDF) bundle pdf-lib (MIT License, Copyright (c) 2019 Andrew Dillon). The pdf-lib bundle also includes components under Apache-2.0 (such as tslib, Copyright (c) Microsoft Corporation), whose notices are retained inside the file. The character-encoding tools use encoding-japanese (MIT License, Copyright (c) 2012 polygonplanet), and the HTML-to-Markdown tool uses Turndown (MIT License, Copyright (c) 2017 Dom Christie) with its turndown-plugin-gfm plugin (MIT License, Copyright (c) 2017 Dom Christie). The full license text and copyright notice for each is included in the corresponding /assets/js/*.js file.

The PDF-to-image, text-extraction and page-reordering tools bundle pdf.js (Apache License 2.0, Copyright 2024 Mozilla Foundation) and its worker. The full license text is included in the distributed file /assets/js/pdfjs.min.c9e5db6c.js.

Disclaimer

We do our best to keep every tool accurate, but we don't guarantee the accuracy or completeness of results. Use them at your own discretion, and double-check anything important against an authoritative source.

Last updated: 14 July 2026