Are my CSV files uploaded to a server?

No. Everything happens right inside your browser — nothing is ever sent to a server. Your files stay on your computer the entire time, making it completely private and secure.

How many rows can I merge?

You can merge spreadsheets with hundreds of thousands of rows. Everything runs directly on your device using fast background processing, so your browser stays responsive even with large files.

Can I merge Excel files alongside CSVs?

Yes. Raindocs natively parses Excel (.xlsx and .xls) files and extracts sheets, converting them to tabular format so they can be merged directly with CSV files.

What are the limits on file sizes?

The limits are bound by your device's system memory (RAM). In most standard browsers, you can comfortably merge files totaling up to several hundred megabytes in size.

Can I split a CSV into smaller files?

Yes. The Split CSV tool allows you to partition your spreadsheet by a maximum number of rows, target file sizes (in MB), or split it equally into a custom number of parts.

How does duplicate removal work in Raindocs?

You can remove duplicate entries based on specific columns (like email or username) or by comparing entire rows. You also get to choose whether to keep the first or last occurrence of the duplicate row.

100% Client-Side. Your files never leave your device.

Merge CSV Files Online

Combine multiple CSV, Excel or TSV files in seconds. Private, blistering fast, and runs entirely inside your browser.