Every row, accounted for.

Find the exceptions in your CSV. Keep every change accountable.

File and target settingsOpen a CSV or resume saved work

1 Open a source CSV

UTF-8; comma, semicolon or tab. Up to 2 MB, 5,000 records and 50 columns.

Choose CSVFile delimiter

or paste CSV content

No file loaded

2 Set target rules

Contact list demo rules

The demo is not a platform template. After opening your CSV, use its columns for basic checks below, or import target headers for a destination-specific review.

Use target CSV headers

Import or export rules

Rules JSON

Continue later

Save a project to retain original values, edits, mappings, exclusions and drafts. Nothing is saved automatically.

Resume project

Project files contain your data. Store them securely.

Your source stays intact

No guessed dates, invented emails or automatic merges. Your source file is never overwritten.

Closing this page clears memory. Save a project or export before leaving.

Try the sample, or open a CSV to begin.

Source records —

Pass rules —

Need review —

Excluded —

Mappings and checks Waiting for a source

Replaces current target fields and checks with all source columns. Checks record shape and outer whitespace only. Required, unique, email, date and enum checks stay off until you configure them.

Exports use target column order. Dates require YYYY-MM-DD. Enum options are comma-separated; uniqueness compares exact text.

Target fields, source mappings and validation rules
Target field	Source column	Check	Required	Unique	Allowed options

Working copy

contacts-demo.csvExample file

ID	Name	Email	Date
001	Lin, An	an@example.com	2026-10-12
	Maya
	Noah	noah@example.com

Click a highlighted cell to try a review.

A few exceptions.
A clear way forward.

Open your file, or work through the example. Review one row at a time, then export a copy you can explain.

Trim outer whitespace

Preview mapped cells before changing them. Internal spaces and letter case stay intact.

Change history 0 operations

No changes yet.

3 Export a reviewed copy

Waiting for checks

Passing these rules does not guarantee acceptance by your destination. Review its account settings and business rules.

Protect formulas for spreadsheet review. Adds prefixes to =, +, -, @ and other risky values, including some phone numbers. Leave off for destination imports.

UTF-8, comma-separated, CRLF. The audit retains excluded records and before/after values.

Every row, accounted for.

Working copy

A few exceptions.A clear way forward.

Trim outer whitespace

3 Export a reviewed copy

A few exceptions.
A clear way forward.