Key-aware matching
Match by a detected header or by row position when order matters.
Original CSV
Updated CSV
ResultAdd data or load the sample to begin.
| Status | Key | Changed fields | Before | After |
|---|
Basics
Understanding the format
A structured CSV diff compares records and fields rather than raw text. Key matching keeps the same record aligned when rows are reordered.
The result separates added, removed, changed, unchanged, and duplicate-key records.
What it does
What this tool does
Paste or open two files, choose a key such as id, email, or SKU, normalize harmless formatting differences, and filter a field-level audit table.
Noise controls
Optionally ignore case, surrounding whitespace, and null-like placeholders.
Cell-level audit
See changed fields with before and after values plus source row numbers.
Complete export
Download the filtered or full difference report as CSV.
How to use
How to use it
Add both versions
Paste the original and updated CSV, open two files, or load the comparison sample.
Choose matching
Select a unique key; use row position only when both files share the same ordering.
Compare
Review duplicate-key warnings and counts for every result status.
Filter and export
Inspect only changed, added, or removed rows, then copy or download the report.
Errors & limits
Common errors and limits
Duplicate keys
Repeated identifiers are isolated instead of silently overwriting one another.
Different headers
Fields missing from one file appear as changes; align header names before comparing when they mean the same thing.
Formatting-only differences
Use the case, whitespace, and null controls deliberately; they change what counts as equal.
Review
A key must be stable and unique. Duplicate or missing keys are reported separately because matching them automatically could hide or invent changes.
FAQ
Frequently asked questions
Can reordered rows be compared?
Yes. Choose a stable key column and row order will not create false changes.
What key should I use?
Use a unique, stable field such as id, UUID, email, or SKU. The tool suggests likely keys.
Can I compare without a key?
Yes. Position mode compares row 1 with row 1, row 2 with row 2, and so on.
Are files sent to a server?
No. Both datasets and the diff stay in your browser.