Turn messy CSV data into a repeatable cleaning plan.
Compose focused transformations instead of trusting an opaque one-click cleanup. Each step updates the preview while the original rows remain unchanged.
1. Choose a CSV to clean
Your file opens directly in the local app. Contents stay in this browser; no account needed.
Up to 20 MiB, 100,000 rows and 500 columns.
- Choose CSV
- Profile and choose cleanup rules
- Review and download a new CSV
Standardise text values
Trim leading and trailing spaces, collapse repeated whitespace, and apply lower, upper or title case to selected columns. Empty strings can be represented consistently as null values.
Make transformation order visible
Trimming before deduplication can produce a different result from deduplicating first. The plan displays its sequence, so you can reason about the output and undo the latest choice.
Review rows and column profiles
The table shows a bounded preview, while column profiles explain how completeness and uniqueness change. Fuzzy suggestions remain separate from rules that can alter the output.
Export without replacing the source
Local mode processes the complete accepted CSV when you export and downloads a new file. It does not overwrite the original or send its contents to a server.
Frequently asked questions
Does the order of data-wrangling rules matter?
Yes. Trimming values before deduplication can produce a different result from deduplicating first. The tool displays the ordered plan and lets you undo the latest step or reset it.
Is my CSV uploaded when I clean it locally?
No. Local cleaning processes the CSV in this browser without an account. Temporary Loam mode is a separate option and uploads a copy only after you confirm it in the application.
Which files can I clean?
Local mode accepts one CSV up to 20 MiB, 100,000 rows and 500 columns. Export other formats as CSV first. Download your cleaned result before refreshing or closing the tab.
Does cleaning overwrite my original CSV?
No. Rules change a preview that you can undo or reset. Export downloads a separate cleaned CSV and processes the complete accepted file.