Tally is a new in-browser tool designed to help users verify the accuracy of numbers in their spreadsheets against their original data sources. Users can upload .xlsx files or connect Google Sheets, and Tally will recompute every figure directly on their device without uploading any data. This ensures that reports accurately reflect underlying rows, catching discrepancies before they are shared.

Tally offers a "Watch" feature that periodically re-checks connected Google Sheets and alerts users to any changes or inconsistencies. Additionally, the "Prove" function generates shareable links for verified figures, allowing recipients to see the exact rows that support the reported numbers, thus providing proof of accuracy.

The tool also integrates with QuickBooks to reconcile spreadsheet figures against actual invoices, identifying any mismatches. This feature operates in read-only mode, ensuring data security. Tally aims to streamline the verification process, saving users time and preventing errors in financial reporting.