Josh Greenhalgh

Building and open-sourcing ML tooling including an activation-probing toolkit, a weight-perturbation experiment framework, and an LLM-based knowledge-graph extraction pipeline.

Designed and built the data platform and catalogue for 100k+ single-cell samples, unifying scattered sources into a lineage-aware index. Owned storage architecture end to end, built QC and monitoring frameworks, and developed synthetic data generation for model validation.

Rebuilt data pipelines with Prefect orchestration on GCP, led migration to impression-level ingestion, designed a new data warehouse with change data capture, and overhauled revenue estimation reducing variance to under 1%.

Co-founded a two-sided data venture for privacy-preserving mobility aggregates. Built a proof-of-concept mobile app and location collection backend on GCP, later discontinued after finding the model commercially unviable.

Implemented Terraform-managed infrastructure on GCP with revision-based deployments, replaced Cloud Composer with Prefect pipelines, and built satellite imagery processing pipelines on Google Earth Engine for climate analytics.

Built a data quality framework for Redshift using property-based testing, led redesign of marketing cost processing reducing overspend by ~5%, and established Airflow best practices to cut costs.

Led a GSMA-funded project standardizing ETL on Airflow across multiple countries, built a post-crisis mobility analysis tool, led a project estimating commuting flows in Haiti, and delivered training for Nepal's statistics office.

Researched deep learning, optimisation and Bayesian methods for inverse problems in x-ray tomography. Taught and mentored undergraduates and postgraduates.

Completed an MSc in Computational Modelling at the University of Southampton from 2014 to 2015.

Completed a PGCE in Mathematics and achieved Qualified Teacher Status at Manchester Metropolitan University from 2012 to 2014.

Grade: First Class Honours

Earned a BSc in Mathematics with First Class Honours from Manchester Metropolitan University from 2009 to 2012.