CSV Fusion combines multiple CSV files without sending a single row to a server. Append files to stack their rows into one dataset, or merge on a shared key column to join records the way a VLOOKUP or SQL JOIN would. Because the parsing runs on WebAssembly in your own tab, files that choke a spreadsheet — hundreds of thousands of rows, mismatched headers, oddly delimited exports — process locally and stay on your machine.
Appending stacks rows: two files with the same columns become one longer file. Merging joins on a key column, matching rows across files by a shared value like an ID or email — closer to a SQL JOIN or VLOOKUP.
Yes. You map which columns line up instead of needing identical headers, so exports from different tools can still be combined.
No fixed cap. Processing happens in your browser, so the practical limit is your device's memory. Files with hundreds of thousands of rows work fine on most machines.
Every tool runs entirely in your browser. Files are never uploaded — 100% private and free.