Private browser-based CSV comparison

Compare two CSV files and spot real data changes.

CSVDiffTool auto-detects delimiters, lets you choose a primary key, highlights added rows, removed rows, and modified cells, then exports the diff report as CSV without uploading anything.

Up to 5MB per file No backend Primary-key matching CSV export

Step 1

Load two CSV files

Files stay on device

CSV A

Baseline file

Drop the first CSV file

Click to browse or drag a file here. Supports CSV up to 5MB.

File: No file selected
Rows: 0
Delimiter: -

CSV B

Incoming file

Drop the second CSV file

Compare new exports, revisions, or customer data snapshots.

File: No file selected
Rows: 0
Delimiter: -

Step 2

Match rows and compare

Waiting for files

Primary key column Choose a shared column like `id`, `email`, or `sku` to match rows correctly.

Comparison mode Awaiting both files Files are aligned by row order until you pick a shared key.

Rows ready 0 / 0 The first number is CSV A, the second is CSV B.

Step 3

Diff summary and export

Added Removed Changed

Rows added 0

Rows removed 0

Rows changed 0

Rows unchanged 0

Rows compared 0

Comparison notes

Warnings appear here for parse problems, blank keys, or duplicate keys.

Upload both CSV files to generate comparison notes and diff results.

CSV A preview

First 50 aligned rows

Load a CSV file to preview the left side.

CSV B preview

First 50 aligned rows

Load a CSV file to preview the right side.

Detailed diff report

The table shows the first 200 differences. Full results stay available in exported CSV files.

Status	Primary key	Occurrence	Row in A	Row in B	Changed columns
No comparison report yet.

Why developers use CSVDiffTool

Compare CSV exports before imports, sync jobs, or production releases.

This tool is designed for data engineers, analysts, backend developers, and operations teams who need to verify CSV changes quickly. Use it to inspect vendor feeds, compare before-and-after reports, audit migration results, or validate nightly exports.

How the browser-only comparison works

CSVDiffTool reads both CSV files locally, detects whether they use commas, semicolons, or tabs, and parses quoted fields without uploading data to a server. When you choose a primary key, rows are matched by that column. If you leave the key on row order, the tool compares rows by position.

What counts as a CSV difference

Added rows exist only in CSV B. Removed rows exist only in CSV A. Changed rows exist in both files but one or more cell values differ. Modified cells are highlighted directly inside the side-by-side tables so you can see exactly what changed.

Useful primary keys for CSV comparison

`id` for exported database records
`email` for marketing or CRM lists
`sku` for ecommerce inventory snapshots
`order_number` for financial reconciliation files