Campaign URL QR Code Builder

Campaign URL QR Code Builder is an open‑source, self‑contained ASP.NET Core application for generating fully trackable campaign URLs and QR codes with UTM parameters.

It is designed to be simple, private, and easy to deploy—no database, no authentication, no external services required. The application is distributed as a Docker image and can be self‑hosted or run locally in seconds.

Features

• Build URLs with all standard UTM parameters (utm_source, utm_medium, utm_campaign, utm_id, utm_term, utm_content)
• Auto-extracts existing UTM parameters when you paste a URL that already contains them
• Generates a 512 × 512 QR code in real time
• Optional centered image overlay (square PNG, max 5 MB, resized to 128 × 128)
• Save/load campaign configurations in browser localStorage
• Share a full configuration via a single URL (state encoded in query parameters)
• Download the finished QR code as a PNG

Tech Stack

Layer	Technology
Runtime	.NET 8 / ASP.NET Core (static-file host only)
Frontend	Vanilla HTML 5, CSS 3, JavaScript (no framework)
QR library	QRCode.js (bundled locally)
Storage	Browser localStorage (no database)

Security

The server applies the following headers to every response:

Header	Value
Content-Security-Policy	default-src 'self'; scripts from self + jsdelivr CDN; fonts from Google Fonts
X-Content-Type-Options	nosniff
X-Frame-Options	SAMEORIGIN
Referrer-Policy	strict-origin-when-cross-origin

For production deployments it is strongly recommended to place the container behind a TLS-terminating reverse proxy (nginx, Caddy, Traefik, etc.) and add Strict-Transport-Security.

Running locally (without Docker)

Prerequisites: .NET 8 SDK

dotnet run --project qrcodes.csproj

The app listens on http://localhost:5000 by default. Open that URL in a browser.

Docker

Quick start

Pull the image from Docker Hub and run it:

docker run --rm -p 4278:4278 kmsigma/utm-qrcodes:latest

Open http://localhost:4278 in a browser.

Deployment with Docker Compose

Prerequisites

• Docker Engine 24+
• Docker Compose v2 (included with Docker Desktop)

Start

docker compose up -d

Pulls the image from Docker Hub (if not already cached) and starts the container in the background. The app is available at http://localhost:4278.

Stop

docker compose down

Update to the latest image

docker compose pull && docker compose up -d

Configuration

Environment variable	Default	Description
ASPNETCORE_ENVIRONMENT	Production	ASP.NET Core environment name
ASPNETCORE_URLS	http://+:4278	Listening address inside the container

To change the host port, edit the ports mapping in docker-compose.yml:

ports:
  - "80:4278" # expose on host port 80 instead

Building from source

If you want to modify the code and test your changes locally, build the image yourself:

docker build -t utm-qrcodes:local .
docker run --rm -p 4278:4278 utm-qrcodes:local

Production notes

• The container runs as a non-root user (appuser).
• The filesystem is mounted read-only (read_only: true) with a tmpfs at /tmp.
• no-new-privileges is set to prevent privilege escalation.
• Place the container behind a reverse proxy to handle TLS, rate limiting, and access control.

License

This project is licensed under the MIT License.

You are free to use, modify, and distribute this software, including for commercial purposes. See the LICENSE file for details.