The latest articles on DEV Community by clarecui (@clarecui). https://dev.to/clarecui 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%2F487756%2Fbe2d423e-2bb2-4cd3-beb8-3c234e580bd4.jpeg https://dev.to/clarecui en clarecui Mon, 28 Sep 2026 09:35:29 +0000 https://dev.to/clarecui/i-built-an-ai-excel-tool-that-never-uploads-your-files-heres-how-59oi https://dev.to/clarecui/i-built-an-ai-excel-tool-that-never-uploads-your-files-heres-how-59oi <p>I just launched FormulaAI — an AI-powered Excel tool with a privacy-first approach.</p> <h2> The Problem </h2> <p>Most AI Excel tools upload your entire file to their servers. </p> <p><a href="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Farticles%2Fqnp0rkapfb1873gkf74k.jpg" class="article-body-image-wrapper"><img src="https://media2.dev.to/dynamic/image/width=800%2Cheight=%2Cfit=scale-down%2Cgravity=auto%2Cformat=auto/https%3A%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Farticles%2Fqnp0rkapfb1873gkf74k.jpg" alt=" " width="800" height="600"></a><br> Your financial data, customer lists, sensitive business info — <br> all sitting on someone else's server.</p> <p>I wanted something different.</p> <h2> What FormulaAI Does </h2> <p>Two core features:</p> <ol> <li><p><strong>Edit Tables</strong>: Upload Excel → describe what you want in plain English → AI modifies it → see every change in a diff view → confirm and download.</p></li> <li><p><strong>Generate Tables</strong>: No file needed. Just describe what you want, like "generate a March sales budget with categories, budget amount, actual spend, and variance." AI creates a complete spreadsheet.</p></li> </ol> <h2> Privacy Architecture </h2> <p>Files are parsed locally in the browser using SheetJS. Only data summaries are sent to the AI for processing. Nothing is stored on the server. After processing, everything is deleted.</p> <h2> Tech Stack </h2> <ul> <li>Next.js + TypeScript</li> <li>DeepSeek API</li> <li>SheetJS</li> <li>Supabase</li> <li>Cloudflare Pages</li> </ul> <h2> Pricing </h2> <p>Free tier with monthly quota. Paid plan for unlimited usage.</p> <p>Early supporters who signed up before launch get a permanent discount.</p> <h2> Try It </h2> <p>👉 <a href="https://formulaai.net" rel="noopener noreferrer">https://formulaai.net</a></p> <p>I'd love to hear your feedback!</p> ai programming productivity tutorial