The latest articles on DEV Community by Declan (@buildittheywillcome). https://dev.to/buildittheywillcome 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%2F4080417%2F6234aad3-9d57-4cd3-a0d1-916f9a1fff03.jpg https://dev.to/buildittheywillcome en Declan Thu, 20 Aug 2026 18:42:48 +0000 https://dev.to/buildittheywillcome/building-file-utilities-that-run-100-in-the-browser-ie4 https://dev.to/buildittheywillcome/building-file-utilities-that-run-100-in-the-browser-ie4 <p>I recently built filetools, a suite of file utilities that run entirely in the browser. No server backend, no file uploads, no data collection.</p> <h2> The Problem </h2> <p>Existing tools for CSV extraction, PDF manipulation, and table conversion often require uploading files or creating accounts. That creates friction and privacy concerns. But these tasks are fundamentally simple: extracting text from a PDF or parsing a CSV can happen entirely in JavaScript.</p> <h2> The Solution </h2> <p>filetools is a collection of single-purpose utilities:</p> <p><strong>PDF Tools:</strong></p> <ul> <li>Merge, split, rotate PDFs</li> <li>Extract tables from PDFs to CSV</li> <li>Convert bank statements to CSV</li> </ul> <p><strong>Data Tools:</strong></p> <ul> <li>Extract tables from HTML to CSV or JSON</li> <li>Convert between XLSX, JSON, YAML, and CSV</li> <li>Remove duplicate lines, sort CSV files, merge/compare data files</li> </ul> <p>Each tool is its own page, targeting one specific task without bloat.</p> <h2> Architecture </h2> <p><strong>Why static hosting?</strong> Keeps infrastructure simple and costs near zero. Files are built once, served from GitHub Pages.</p> <p><strong>Why client-side only?</strong> User files never leave their machine. Processing is fast (no network round-trip). Privacy is the default.</p> <p><strong>Tech stack:</strong> vanilla JavaScript using npm libraries (pdfjs-dist, exceljs, js-yaml, pdf-lib) - no framework, no server. Each page is roughly 5-15KB gzipped.</p> <p><strong>Design:</strong> Started with demand mining, looking at actual Google search queries and autocomplete suggestions to pick which tools to build first.</p> <h2> What's Next </h2> <p>Live site: <a href="https://usefiletools.com/?utm_source=dev.to&amp;utm_medium=article&amp;utm_campaign=filetools-launch">https://usefiletools.com/?utm_source=dev.to&amp;utm_medium=article&amp;utm_campaign=filetools-launch</a></p> <p>I'm building more tools based on real search demand. If there's a file utility you've always wished existed, especially for data professionals, I'd love to hear about it.</p> javascript webdev privacy tooling