Browser Tool
Free CSV Diff Tool
Compare two CSV files and instantly see what changed. Added rows, removed rows, modified cells.100% Client-Side. Your data never leaves your browser.
Original File
The baseline version
Updated File
The new version to compare
Why this matters
Client files change constantly.
Implementation projects are iterative. Clients send updated files, corrections, and revisions. Manually scanning thousands of rows to find what changed is slow and error-prone.
- Instant visual diff of added, removed, and changed rows
- Position-based or key-based comparison
- Handles files with thousands of rows
- No data uploaded to any server
Need to transform the changes?
Seeing what changed is step one. Implementation teams use DataFlowMapper to build reusable transformation templates that handle the full workflow: mapping, validation, and output generation.
Client-Side Processing ArchitectureSecure
Your data never leaves your device. All processing happens locally in your browser's memory via WebAssembly/JavaScript. This ensures complete data sovereignty and compliance with GDPR, HIPAA, and SOC2 standards as no files are uploaded to our servers.
Frequently Asked Questions
What types of changes does it detect?▼
The tool detects three types of changes: added rows (new in the updated file), removed rows (missing from the updated file), and modified rows (same row position or key, but cell values changed). Modified cells are highlighted within each row.
What is the difference between position-based and key-based comparison?▼
Position-based compares row 1 to row 1, row 2 to row 2, etc. Key-based uses a unique identifier column (like Account ID or Email) to match rows regardless of their order. Use key-based when rows may have been reordered between file versions.
What happens if my key column has duplicates?▼
If duplicate keys are detected, the tool will show a warning and use the first occurrence of each key. For files with non-unique identifiers, position-based comparison is recommended.
Is my data secure?▼
Yes. This tool runs 100% in your browser. Your files are processed locally and never uploaded to any server. We cannot see your data.
Is there a row limit?▼
There is no hard limit. Processing happens in your browser, so performance depends on your device. Most modern laptops handle files with tens of thousands of rows without issue.
The visual data transformation platform that lets implementation teams deliver faster, without writing code.
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