Excel・CSV差分比較・データ照合ツール

Overview #Personal Development

A web application that matches two Excel/CSV files using matching keys and column mappings, normalizes the data, and deterministically calculates record and cell-level differences. All processing is completed within the browser, and input files and data are not sent to the server.

Main Features

• File Import: Drag & drop for CSV/XLSX, supports multiple sheets
• Column Mapping: Map different column names 1-to-1, selectable comparison formats (string, numeric, date)
• Matching Key: Identify identical records using single or composite keys
• Normalization: Flexibly unify whitespace, case, character width, line breaks, and numeric/date notation (original data preserved)
• Difference Classification: Automatically determine Added/Removed/Changed/Unchanged
• Duplicate & Error Detection: Isolate and display duplicate keys, missing keys, and normalization errors
• Filter & Search: Narrow results by judgment, changed columns, and search terms; paginated display
• Settings Persistence: Save matching templates to browser and reuse the same matching workflow
• Report Export: XLSX report (8 sheets), CSV, clipboard copy

Target Users

Intended for staff who regularly handle CSV/Excel in accounting, sales administration, EC operations, information systems, data migration, inventory management, back-office operations, and similar roles.

Example Use Cases

• Monthly customer master difference verification
• Product price change before/after comparison
• Invoice and payment reconciliation
• Data migration validation from legacy to new systems
• Physical inventory vs. system inventory reconciliation

Technical Characteristics

• Local-first design: Input files and data are not sent to the server
• Deterministic matching: Always returns the same results for identical inputs
• Web Worker processing: File parsing and matching executed in the background
• Non-destructive original data: Normalization applied only to comparison values for matching
• Responsive UI: Compatible with desktop, tablet, and mobile devices