Maximilian Held

I'm an expert R developer and DevOps engineer, with 12 years of experience in industry, research and open source. I build reproducible, maintainable and scalable full-stack data products.

I focus on bringing software development best practices to data science, using defensive programming, test-driven development, CI/CD and source control management.

Though not a computer scientist by training, I have come to love just building something that saves another human being a lot of time, or perhaps, even serves her in solving an important problem.

I have also learned (the hard way) that software development, in R as elsewhere, is not without risks. I work best when I understand the users needs well, and can break it down into small, modular, and well-tested pieces. This requires a lot of focus and "saying no" (mostly to oneself).

Owner at Max Held Data Products (2019 – Present)

I consult clients as a freelance developer and build data products.

Improving Performance of a Large Shiny App (2024 – 2025)

I rebuild several packages for a large shiny app used by hundreds of internal customers weekly. I addressed performance bottlenecks and improved maintainability by refactoring functionality into modules and applying parallel and async patterns.

Implementation of Default Risk Model (2024 – 2024)

I built a shiny app for internal use at a national financial institution, including extensive unit tests and client feedback.

Re-Implementation of a Financial Model (2022 – 2023)

I rebuilt a spreadsheet-based financial model in R, complete with a Shiny frontend and extensible API. Because the package needed to be reproducible and cross-validated against legacy software, excel results could be reproduced from R in full.

Consulting on Containerisation, Cloud Migration (2022 – 2023)

I consulted the client on improving their R shiny development infrastructure and hosting. I build an end-to-end proof-of-concept CICD pipeline from version-controlled source code to containerised cloud deployment using Azure App Service.

Transitioning DevOps and Refactoring R Code at Immunai, Inc. (2021 – 2023)

I standardised the compute environment for biotech workloads across development, research and production for across several locations with dozens of internal modules, hundreds of external dependencies. To meet the heightened need for reproducibility in the industry, images were fully versioned, efficiently cached and rebuilt on every commit. I also productionised several internal R packages and helped the client strengthen best practices.

Code Review (2021 – 2021)

I conducted comprehensive code review of an extensive shiny application and advised the client on future design patterns and architecture.

Consulting on Inventory Management Automation in R (2021 – 2021)

I consulted the client on the design of inventory management automation project in R.

Build R DevOps for GitHub Actions at Posit, PBC (2019 – 2019)

I built the open-source ghactions package for the continuous integration and continuous delivery (CICD) product from GitHub for the leading R development house for use by the tidyverse team.

Data Analyst at Lower Saxony State- and University Library Göttingen (2020 – 2021)

I developed ETL pipelines, dashboards and data DevOps solutions for bibliometric data to assist the library and associated organisations in contract negotiations and compliance.

Research Associate at University of Hohenheim / Friedrich-Alexander Universität Erlangen-Nürnberg (2016 – 2020)

I wrote software for a specialised psychometric method (Q), as well as one-off analyses of economic data.

Research Associate at Jacobs University Bremen (2014 – 2016)

I conducted and analyse behavioral economic experiments in Jan Lorenz's computational social science group on Opinion Dynamics and Collective Decisions. I implemented an agent-based model in R.

Instructor and Manager at Deutsche SchülerAkademie / Bildung und Begabung gGmbH (2003 – Present)

Summer camps for gifted students.

PhD Studies in Public choice and taxation – Bremen International Graduate School of Social Sciences (2010 – 2016)

Graduate Studies in Public Policy – Hertie School of Governance (2008 – 2010)

Graduate Studies in Demography – University of California, Irvine (2007 – 2008)

Bachelor of Arts in Integrated Social Sciences – Jacobs University Bremen (2004 – 2007)