Free File Merger Online — No Signup Required

A file merger combines the contents of multiple files into a single output file. The most common use case is merging text-based files: combining multiple CSV exports from different time periods into one dataset, concatenating log files from multiple servers, merging multiple Markdown files into a single document, or combining several JSON arrays into a unified dataset. This eliminates the manual process of opening each file, copying its contents, and pasting into a combined file.

This browser-based merger accepts multiple text, CSV, JSON, and Markdown files via drag-and-drop. You can set the order by dragging files in the file list, configure the separator between files (none, newline, `---` divider, or custom text), and choose whether to include or exclude header rows when merging CSVs (to avoid repeating the header from each file). The merged result is available for download in a single file.