Structured data
CSV Diff Viewer
Review exactly how two CSV exports differ before replacing or importing data.
Processed locally. Your input and output are never uploaded.
Tool overview
How CSV Diff Viewer works
CSV Diff Viewer compares two CSV inputs by named keys or row position and distinguishes added, removed, and changed cells. It keeps input and output separate, runs locally, and documents boundaries instead of making unsupported guarantees.
Audits that need a change list
- compares two CSV inputs by named keys or row position and distinguishes added, removed, and changed cells. for a repeatable local workflow
- Review pasted or locally opened data before copying it
- Prepare output for a related PasteTidy tool
Compare by key or position
- Paste the source or open a supported local file.
- Paste or open the secondary source when the comparison requires it.
- Choose the documented options and review the separate result.
- Copy or download only after checking the visible output.
Changed cells and retained rows
- Match mode: Compare by key or row position.
- Original key columns: Key names in the original CSV.
- Changed key columns: Key names in the changed CSV.
- Include unchanged cells: Usually leave unchanged cells out.
Review a changed export
Before
Input ยท List A: id,name 1,Ana 2,Bo Input ยท List B: id,name 1,Ana 2,Bea 3,Cia
Result
[
{
"status": "changed",
"key": "2",
"column": "name",
"before": "Bo",
"after": "Bea"
},
{
"status": "added",
"key": "3",
"column": "",
"before": "",
"after": "[\"3\",\"Cia\"]"
}
]Ordering and duplicate-key limits
- Ambiguous or malformed input is reported instead of silently repaired.
- Large input is bounded by the documented local worker limits.
- Input, options, and output are not sent to analytics or placed in URLs.
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Questions
CSV Diff Viewer FAQ
Does CSV Diff Viewer upload my input?
No. Processing stays in the current browser tab or its local Web Worker.
Is the result authoritative?
No. Review the output and the documented limitations before using it in a production workflow.