Dereferrer Service

This small service aims to prevent links to be tracked by the website they are linking to. It takes the URL as a parameter and returns a redirect to the URL with the referrer header removed. Especially useful for privacy-aware sites.

Imagine you serve this service on https://dereferrer.example.com and you want to link to https://example.com. Instead of linking to https://example.com directly, you link to https://dereferrer.example.com/?https%3A%2F%2Fexample.com. The service will then redirect you to https://example.com with the referrer header replaced with https://dereferrer.example.com.

Important: The query parameter should be URL encoded.

Usage

Environment Variables

Variable	Description	Default
LISTEN_ADDR	Address to listen on	:8080
METRICS_ADDR	Address to listen on for metrics	:8081
LOG_LEVEL	Log level	info

Docker

docker run -p 8080:8080 -p 8081:8081 -d --name dereferrer \
docker.io/systemli/dereferrer:latest

The service needs no special capabilities and can start as read-only.

docker run -p 8080:8080 -p 8081:8081 -d --name dereferrer \
--read-only --cap-drop all \
docker.io/systemli/dereferrer:latest

Go

go install github.com/systemli/dereferrer@latest
dereferrer

Metrics

The service exposes metrics on the /metrics endpoint on port 8081. The metrics are compatible with Prometheus.

Exported metrics:

# HELP requests_total Number of requests
# TYPE requests_total counter
requests_total{status="200"} 6145
requests_total{status="400"} 619
requests_total{status="404"} 651
requests_total{status="405"} 35

License

This project is licensed under the GPL-3.0 License - see the LICENSE file for details.