Rosetta

An Excel translation tool that preserves formatting, formulas, and data integrity.

Overview

Rosetta takes an Excel file as input, translates all text content using Claude, and outputs a new file with translations — without breaking formulas, styles, merged cells, images, data validations (dropdowns), or any other Excel features.

Features

• Preserves Excel structure: Formulas, formatting, merged cells, charts, images, and data validations remain intact
• Rich text formatting: Preserves bold, italic, colors, and fonts within cells
• Dropdown translation: Translates inline dropdown values (e.g., "Yes,No,Maybe")
• Context-aware translations: Provide domain context for more accurate translations
• Smart extraction: Only translates text content, skips formulas and numbers
• Sheet selection: Translate all sheets or select specific ones with --sheets
• Multiline support: Correctly handles cells with multiple lines of text
• Batch processing: Efficient API usage with configurable batch sizes
• Multiple language support: Any language pair supported by Claude

Installation

git clone https://github.com/ewalid/rosetta.git
cd rosetta

Then install dependencies:

# Using uv (recommended)
uv sync

# Or using pip
pip install .

Usage

# Basic usage (translates all sheets)
rosetta input.xlsx -t french -o translated.xlsx

# Specify source language (auto-detected by default)
rosetta input.xlsx -s english -t spanish

# Translate specific sheets only
rosetta input.xlsx -t french --sheets "Sheet1" --sheets "Data"

# Custom batch size (default: 50 cells per API call)
rosetta input.xlsx -t german -b 100

# Provide context for domain-specific translations
rosetta input.xlsx -t french -c "This is a medical document with clinical terminology"
rosetta input.xlsx -t spanish -c "Marketing content for a software company"

CLI Options

Option	Short	Description
--target-lang	-t	Target language (required)
--source-lang	-s	Source language (auto-detect if omitted)
--output	-o	Output file path (default: input_translated.xlsx)
--batch-size	-b	Cells per batch (default: 50)
--sheets		Sheets to translate (can be repeated, default: all)
--context	-c	Additional context for accurate translations

Configuration

Set your Anthropic API key:

export ANTHROPIC_API_KEY=your_key_here

Optional environment variables:

export ROSETTA_MODEL=claude-sonnet-4-20250514    # Claude model to use
export ROSETTA_BATCH_SIZE=50                      # Default batch size
export ROSETTA_MAX_RETRIES=3                      # API retry attempts

Project Structure

rosetta/
├── src/
│   └── rosetta/
│       ├── __init__.py
│       ├── models/           # Data models (dataclasses)
│       │   ├── __init__.py
│       │   └── cell.py       # Cell, RichTextRun, DropdownValidation, TranslationBatch
│       ├── services/         # Business logic (framework-agnostic)
│       │   ├── __init__.py
│       │   ├── extractor.py  # Excel cell extraction
│       │   └── translator.py # Claude API integration
│       ├── core/             # Configuration and exceptions
│       │   ├── __init__.py
│       │   ├── config.py     # Environment config
│       │   └── exceptions.py # Custom exceptions
│       ├── api/              # FastAPI routes (future: web interface)
│       └── main.py           # CLI entry point
├── tests/                    # Test suite (pytest)
├── pyproject.toml
└── README.md

Architecture: The services/ layer is framework-agnostic and can be used by both the CLI (main.py) and future API endpoints (api/). This allows adding a web interface without refactoring.

Development

Running Tests

# Install dev dependencies
pip install -e ".[dev]"

# Run tests
python -m pytest tests/ -v

# Run tests with coverage
python -m pytest tests/ -v --cov=rosetta --cov-report=term-missing

Requirements

• Python 3.11+
• Anthropic API key

License

MIT