The latest articles on DEV Community by toolsdocks (@toolsdocks). https://dev.to/toolsdocks https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4202322%2Fa891eda1-8ed5-431f-a5dc-67464c1c673b.png https://dev.to/toolsdocks en toolsdocks Fri, 23 Oct 2026 10:30:25 +0000 https://dev.to/toolsdocks/i-built-167-browser-tools-that-dont-upload-your-files-heres-what-i-learned-9d5 https://dev.to/toolsdocks/i-built-167-browser-tools-that-dont-upload-your-files-heres-what-i-learned-9d5 <p>Most free "online tools" work the same way: you upload your PDF or photo to someone's server, wait, then download the result. Often there's a watermark, a daily limit, or a signup wall after two tries.</p> <p>I wanted the opposite, so I built <a href="https://www.toolsdocks.com" rel="noopener noreferrer">toolsdocks</a>: 167 free tools for PDFs, images, video, audio, text, spreadsheets and everyday calculations. Most of them run entirely in your browser.</p> <h2> Why process files in the browser? </h2> <ul> <li> <strong>Privacy:</strong> a contract, an ID scan or a family photo never leaves your device.</li> <li> <strong>Speed:</strong> no upload and no download for large files. A 200 MB video does not have to travel anywhere.</li> <li> <strong>No limits:</strong> your own computer does the work, so there is no reason to cap usage or force an account.</li> </ul> <h2> How it works </h2> <p>The site is built with Next.js, and every tool page is static. The heavy work happens in the browser:</p> <ul> <li> <strong>Video and audio:</strong> WebAssembly builds of media libraries convert MP4 to MP3, compress video and burn subtitles.</li> <li> <strong>PDFs:</strong> merging, splitting, signing and filling forms happen in JavaScript on your machine.</li> <li> <strong>AI tools:</strong> speech-to-text, summarizing and background removal download a model once and then run locally.</li> </ul> <p>Each tool page states clearly whether anything leaves your device. A few tools, like DNS lookup or a broken-link checker, need the network by nature, and they say so.</p> <h2> Three hard problems </h2> <ol> <li> <strong>Big files on phones.</strong> Mobile browsers have tight memory limits, so tools process files in chunks and warn before a file gets too large.</li> <li> <strong>First load size.</strong> Media libraries are big, so each tool loads only its own code, and only when you open it.</li> <li> <strong>Honest labels.</strong> "No upload" has to be true for every tool that claims it, so it is set per tool, never site-wide.</li> </ol> <h2> Some of the tools </h2> <ul> <li><a href="https://www.toolsdocks.com/tools/pdf-merge-split" rel="noopener noreferrer">Merge or split PDF</a></li> <li><a href="https://www.toolsdocks.com/tools/heic-to-jpg" rel="noopener noreferrer">HEIC to JPG</a></li> <li><a href="https://www.toolsdocks.com/tools/mp4-to-mp3" rel="noopener noreferrer">MP4 to MP3</a></li> <li><a href="https://www.toolsdocks.com/tools/image-resizer" rel="noopener noreferrer">Image resizer</a></li> <li><a href="https://www.toolsdocks.com/tools/json-formatter" rel="noopener noreferrer">JSON formatter</a></li> <li><a href="https://www.toolsdocks.com/tools/regex-tester" rel="noopener noreferrer">Regex tester</a></li> </ul> <p>It's free and supported by ads, which stay off on pages where you work with your own files.</p> <p>I'd love feedback: which tool would you use, and what's missing?</p> webdev javascript privacy showdev