Quiet Signals
Lab

Alexander Hepburn
ML & Privacy Engineer
Amsterdam, NL

Privacy engineering for machine learning systems

Quiet Signals Lab is an independent ML practice building software and publishing applied research. The focus is on systems where privacy and auditability are properties of the architecture.

About

Thanks for visiting my website!


My name is Alexander, I am from Amsterdam. I started Quiet Signals Lab in 2026 as a platform to pursue my interest in responsible and private AI. I strongly believe that technology does not need to come at the expense of human rights. This venture is my attempt at that.


I hold a master's degree in data science from the University of Amsterdam. My thesis was on addressing distribution shifts in low-resource NLP tasks, supervised by Prof. Paul Groth (INDELab).


Don't hesitate to drop me a message if you are interested in what I do.

Software

ShadowClip app icon

ShadowClip

Computer Vision Privacy Coming June 2026

A macOS and iOS utility for redacting sensitive content from screenshots before they reach AI tools, colleagues, or support tickets. All detection runs on-device — Apple Vision for faces and text layout, Natural Language for named entities, and hand-authored patterns for API keys and structured credentials — with no network entitlement and no data in transit.

Coming to the App Store
RAG Assistant for Zotero icon

RAG Assistant for Zotero

Knowledge Discovery Local AI Provenance ★  … Apache 2.0

A desktop application for semantic search over Zotero research libraries. Designed for researchers who need to navigate large literature collections and get answers with clear source attribution — not summaries that obscure where the information came from. Supports local LLMs end-to-end, so libraries containing preprints, embargoed work, or sensitive material never leave the user's machine.

macOS · Apple Silicon · Homebrew brew tap Quiet-Signals-Lab/rag-assistant-for-zotero brew install --cask rag-assistant-for-zotero
View on GitHub →

Contractex

Python Library Information Retrieval Provenance PyPI ··· ↓ ··· Apache 2.0

ContractEx is a Python library for legal document intelligence. Every operation is a composable LegalTask that takes a LegalDoc and returns a LegalDoc, making it trivial to build privacy-respecting extraction pipelines, RAG chatbots, and document-automation workflows over contracts, statutes, regulations, identity documents, and more. Privacy controls are a mandatory first-class stage in every pipeline.

pip · Python 3.9+ pip install contractex
View on GitHub → View on PyPI →

Blog

Four controlled ablations that isolate when multi-task learning helps, when it hurts, and why — including the data-duplication control that separates task interaction from raw data volume.

Read →