Julian Kie

A prototype of zero-data-custody Excel spreadsheet sharing app. Here's my story: Many companies in small markets still rely on Excel spreadsheets for managing customer data. The dilemma I kept hearing was a familiar one: they cannot afford a robust CRM, but continuing with Excel means accepting real data privacy, governance, and security risks. The entire spreadsheet gets shared with people who only need to see a few columns. There is no audit trail. Once a file leaves your hands, you might have already lost control. I kept thinking about how to help these companies continue using what they know — Excel — but with the kind of data protection features a proper CRM system would give them. And critically, without asking them to trust yet another tool with their data. That last point matters. Most data protection tools solve one problem by creating another. Your data leaves your hands and lands on someone else's servers. For companies already worried about data privacy, that is not a solution. That is just a different risk. So the non-negotiable principle I started with was simple: the tool must never keep your data. Every byte must live exclusively in your own infrastructure. The tool is just a control layer sitting on top of your spreadsheet. You own everything it touches. When I came across the LegalQuants hackathon, I saw it as a just-in-time opportunity to test this idea and start building. With access to Replit, I built SheetProtect — a prototype access control layer for Excel files that does what, and I say this boldly, SharePoint and OneDrive simply cannot: 🔒 Share only specific cells, rows, columns, or ranges — never the whole file 👁️ Data served through a secure web viewer — no raw file, no downloads, no attachments 🎯 Role-based access control down to the individual cell 🏠 Zero data custody — your spreadsheet data, permission rules, audit logs, recipient records, authentication sessions, account credentials, and encryption keys are never held by the app 📋 Every view, edit, and access permanently logged in a tamper-evident audit trail that only you can export This is still a prototype. It is not production-ready and there is plenty more to build and fix. But beyond the product itself, this hackathon marks something personally meaningful. It is my first step in taking an idea all the way through to a working build using AI and vibe-coding as a non-technical person. And a humbling reminder that technical knowledge still matters enormously when it comes to knowing what you are building and why. It has been quite a ride.