CSV Cleaner & Validator - Fix Messy CSV Fast
What is a CSV cleaner?
The CSV cleaner auto-detects delimiters, trims whitespace, drops empty rows, and removes duplicates so you can get a clean CSV or a quick JSON preview without opening spreadsheets. Everything runs in your browser.
How to use the CSV cleaner
- Paste CSV: Drop your data into the input box.
- Pick delimiter: Leave on “Auto-detect” unless you know it (comma, tab, semicolon, pipe).
- Choose cleanup: Keep “Trim whitespace” and “Drop empty rows” on; toggle “Remove duplicates” if needed.
- Export: Select CSV or JSON preview, then copy the output.
Why use this CSV cleaner?
- Fast normalization: Fix headers and rows without opening a spreadsheet.
- Dedupe safely: Remove identical rows after trimming.
- Privacy-first: Parsing happens locally; your data stays in your browser.
Use case 1: Marketing lists
Paste lead exports, trim spaces, drop blank lines, and dedupe before uploading to your ESP.
Use case 2: Analytics snippets
Clean small data extracts from dashboards and preview as JSON for quick API mocks.
Use case 3: Dev fixtures
Normalize CSV inputs before importing into tests or seed scripts.
Examples
Basic example
Input:
email , plan , country
user@example.com , pro , US
user@example.com , pro , US
Settings: trim, drop empty rows, dedupe = on.
Output (CSV):
email,plan,country
user@example.com,pro,US
JSON preview
Same input with export = JSON → returns first 100 rows as objects:
[{ "col_1": "email", "col_2": "plan", "col_3": "country" }, ...]
Common errors
Wrong delimiter detected
Manually pick the delimiter if auto-detect guesses wrong (e.g., many commas inside quoted text).
Quotes doubled
If you see doubled quotes, the source had escaped quotes; the cleaner keeps them valid. Remove extra quotes in source if they were unintended.
Tips and proven approaches
- Keep headers consistent; the tool does not rename columns—fix header typos before deduping.
- To remove duplicate emails regardless of case, run the email column through the lowercase tool first.
- If you only need one column, clean, then extract with the duplicate line remover.
Related tools
- Encode or decode URLs in your CSV with the URL encoder.
- Format or minify JSON exports with the JSON formatter and JSON minifier.
- Compare before/after files with the diff tool.
Privacy and security
CSV parsing and cleaning happen locally in your browser. No data is uploaded or stored. JSON preview is generated client-side from the cleaned rows.