CSV Diff Checker

File A (Original)
Drop CSV file here
File B (Modified)
Drop CSV file here

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What is CSV Diff Checker?

CSV Diff Checker is a developer tool that compares two CSV files using key-based matching instead of line-based diff. It detects added, removed, and modified rows with field-level change highlighting. Everything runs 100% in your browser — your data never leaves your machine.

How to compare CSV files

1. Paste or upload your original CSV in the left panel and the modified CSV in the right panel. 2. Select a key column (auto-detected or manual) for row matching. 3. Configure options: delimiter, case sensitivity, whitespace trimming. 4. Click Compare to see the diff results. 5. Switch between Table, Grouped, Side-by-Side, and JSON views. 6. Filter by change type, column, or search keyword. 7. Export results as JSON or CSV.

Features

  • Key-based diff — matches rows by primary key, not line position.
  • Field-level changes — highlights exactly which cells changed.
  • 4 view modes — Table with cell highlighting, Grouped diff, Side-by-Side comparison, and raw JSON.
  • Column insights — shows per-column change statistics.
  • Smart filtering — filter by change type, column, or search keyword.
  • Drag & drop upload — supports CSV, TSV, and text files.
  • Configurable parsing — delimiter, header toggle, whitespace trimming, case sensitivity.
  • Export — download diff as JSON or CSV.
  • Fullscreen mode — expand results for large datasets.
  • 100% client-side — your data never leaves the browser.

Use cases

  • Comparing database exports before and after migrations.
  • Validating CSV data transformations in ETL pipelines.
  • Reviewing config file changes (feature flags, pricing tables).
  • QA testing — comparing expected vs actual CSV output.
  • Debugging data sync issues between systems.
  • Auditing spreadsheet changes across versions.