Redline API

A high-performance .NET API that compares two DOCX documents and returns a redlined document with tracked changes. Built with FastEndpoints for minimal overhead and maximum throughput.

Features

• Compare two Word documents and generate a redlined version with tracked changes
• Automatic cleanup of comparison artifacts for Word compatibility
• Converts complex move operations to simple del/ins for maximum compatibility
• JWT Bearer authentication support (configurable)
• Docker-ready deployment

Tech Stack

• .NET 10 - Latest LTS runtime
• FastEndpoints - High-performance minimal API framework
• Docxodus (WmlComparer) - Document comparison engine
• DocumentFormat.OpenXml - OOXML manipulation

Quick Start

Prerequisites

• .NET 10 SDK
• Docker (optional, for containerized deployment)

Run Locally

dotnet run

The API will start on http://localhost:5003 by default.

API Usage

curl -X POST http://localhost:5003/api/compare \
  -F "Original=@original.docx" \
  -F "Modified=@modified.docx" \
  -F "Author=Your Name" \
  --output redlined.docx

Parameters

Parameter	Type	Required	Description
Original	File	Yes	The original document
Modified	File	Yes	The modified document
Author	String	No	Author name for tracked changes (default: "User")

Response

Returns the redlined DOCX file with tracked changes showing all differences between the two documents.

Docker Deployment

Build

docker build -t redline-api .

Run

docker run -p 8080:8080 redline-api

With Authentication

docker run -p 8080:8080 -e Jwt__Secret="your-secret-key-min-32-chars" redline-api

Configuration

Environment Variables

Variable	Description	Default
ASPNETCORE_URLS	Server binding URLs	http://+:8080
ASPNETCORE_ENVIRONMENT	Environment (Development/Production)	Production
Jwt__Secret	JWT signing secret (min 32 chars)	-

Enable Authentication

1. Set the Jwt__Secret environment variable
2. Remove AllowAnonymous() from CompareDocumentsEndpoint.cs
3. Include Authorization: Bearer <token> header in requests

Project Structure

├── Program.cs                           # Application entry point
├── Endpoints/Compare/
│   └── CompareDocumentsEndpoint.cs      # Document comparison endpoint
├── appsettings.json                     # Configuration
├── Dockerfile                           # Container definition
├── original.docx                        # Sample original document
└── modified.docx                        # Sample modified document

License

MIT