Consulting

12 years of experience in industry, research and open source.

Past clients include Posit, PBC (formerly RStudio), Immunai, Inc. and small and listed companies across a range of industries.

Ad Unix, per aspera1

Expertise

Declarative DevOps

Builds that only work on one machine? Opaque dependencies with possible vulnerabilities?

I turn development environments, build pipelines and production into one, fully reproducible configuration.

You can audit software bill of materials (SBOMs) for compliance and security, and use agentic coding with the confidence of guaranteed rollbacks.

Nix Terraform OpenTofu Docker GitHub GitLab Azure GCP Cloudflare

Functional Data Products

Business still stuck in spreadsheets because dashboards are outdated and inflexible? ETL pipelines that are hard to maintain?

I apply functional programming and tidy data principles to building internal libraries, data integration and endpoints.

You get type-stable outputs and maintainable functions that elegantly compose into large and scalable pipelines that humans and agents can trust.

R tidyverse Shiny Airflow Dagster

Self-Sovereign (ish2) Compute

Want to run LLMs and other workloads without handing your data to someone else? AI bills running wild and overwhelmed by cloud infrastructure?

Using declarative configuration, local-first tooling and modern orchestration, I set up bare-metal systems without the hassle of manual configuration and maintenance.

You get control over the economics and privacy of your most important compute.

NixOS Nomad Local-First Open-Weight Models

Experience

I implemented a default risk model as a Shiny app for a national financial institution, and rebuilt a spreadsheet-based financial model in R, with a Shiny frontend and an API, cross-validated against the legacy Excel results. I also improved the performance and maintainability of a large Shiny app used by hundreds of internal users every week, and consulted on containerisation and cloud migration to Azure.

I built several Shiny apps for internal use at an international insurance group, from requirements engineering to deployment and performance tuning.

For Immunai, I standardised the compute environment for research and production workloads, across several locations, with dozens of internal modules and hundreds of external dependencies. Images were fully versioned, efficiently cached and rebuilt on every commit. I also productionised several internal R packages.

I consulted on inventory management automation in R.

I worked with industrial protocols such as Modbus and EIB/KNX.

I reviewed a large Shiny app for an automotive company.

I worked as a researcher on opinion dynamics and collective decisions, including behavioural experiments and agent-based models. I wrote open source software for Q methodology, a psychometric method, and built ETL pipelines and dashboards for bibliometric data at a university library.

I built the ghactions package for Posit (then RStudio) to bring GitHub Actions to the R community. I maintain several R packages and the nullkomma Nix project, and have contributed to roxygen2, testthat, pkgdown and several Determinate Systems Nix projects.

Let’s talk.

Tell me what you are building, where you are stuck, and your timeline.

Email me Schedule a 30-minute call

Business details

I work independently as Maximilian Held.

Maximilian Held
Stieglitzeck 3
37441 Bad Sachsa
Germany

VAT ID: DE326554152

Full legal details.

Translated: “To Unix, through hardships”.

The Unix philosophy, summarised:

Write programs that do one thing and do it well. Write programs to work together. Write programs to handle text streams, because that is a universal interface.

Doug McIlroy’s Unix philosophy, as summarized in Peter H. Salus, A Quarter Century of UNIX (Addison-Wesley, 1994). Read the excerpt.

Where a managed service is the better choice, I will tell you.