
Freelance developer · Data products & infrastructure
I build data products from end to end: from the underlying data to the app people use and the infrastructure it runs on.
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.
12 years of experience in industry, research and open source. Clients include Posit (RStudio), Immunai and companies in finance, insurance and automotive.
Builds that only work on one machine? Deployments that need a checklist?
I turn environments, CI/CD and cloud resources into versioned configuration. Every build is reproducible and every change is reviewed.
Nix Terraform Docker GitHub Actions Azure GCP
λ
A model stuck in a spreadsheet? A Shiny app that has become slow and fragile?
I build R packages, pipelines and Shiny apps from small, tested functions over tidy data. They are easy to verify, and easy to change.
R tidyverse Shiny testthat REST APIs
Want to run AI and other workloads without handing your data to someone else?
I set up self-hosted and local-first systems on hardware you control. Where a managed service is the better choice, I will tell you.
NixOS Self-Hosting Local-First Open-Weight Models
Selected client projects, research and open source work, by industry.
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, reviewed a large Shiny app for an automotive company, and worked with industrial protocols such as Modbus and EIB/KNX.
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.
Tell me what you are building, where you are stuck, and your timeline.
I will get back to you within a few days.
Loading the calendar connects to Google, which can process your IP address and browser information and use cookies under Google’s privacy policy. You can email me or open the booking page directly instead.
If the calendar does not load, open the booking page directly.
Maximilian Held
Stieglitzeck 3
37441 Bad Sachsa
Germany
Email: info@maxheld.de
VAT identification number pursuant to § 27a UStG: DE326554152
Maximilian Held, address as above.
This website contains links to external websites over whose content I have no control. The respective provider or operator is always responsible for the content of linked pages. Should I become aware of any legal infringements, I will remove such links immediately.
The content on this website is subject to German copyright law. Reproduction, editing or distribution beyond the limits of copyright law requires my written consent.
The controller responsible for data processing on this website within the meaning of the General Data Protection Regulation (GDPR) is:
Max Held
Stieglitzeck 3
37441 Bad Sachsa
Germany
Email: info@maxheld.de
This website does not use its own analytics, tracking or advertising. The Google Calendar booking embed is optional and loads only when you choose to load it.
This website is hosted and delivered by Cloudflare, Inc., 101 Townsend St., San Francisco, CA 94107, USA (“Cloudflare”). When you visit this website, Cloudflare necessarily processes the following data to deliver the website and to protect it against attacks:
The legal basis is Art. 6(1)(f) GDPR. My legitimate interest lies in the secure, reliable and efficient delivery of this website.
I have concluded a data processing agreement with Cloudflare pursuant to Art. 28 GDPR. Cloudflare may process data in the USA. Cloudflare is certified under the EU-U.S. Data Privacy Framework, for which the European Commission has adopted an adequacy decision (Art. 45 GDPR). In addition, Cloudflare has agreed to the EU Standard Contractual Clauses.
For more information, see Cloudflare’s privacy policy.
If you contact me by email, I process the data you provide (such as your name, email address and the content of your message) to handle your request. The legal basis is Art. 6(1)(b) GDPR if your request relates to a contract or pre-contractual measures, and Art. 6(1)(f) GDPR otherwise. I delete this data once it is no longer needed, unless statutory retention obligations apply.
You can book a call through an external Google Calendar booking page or an optional calendar in a booking dialog on this website. The inline calendar does not load until you click “Load Google Calendar”. Loading it connects your browser to Google to fetch the booking page and its resources. Google can process your IP address, browser information and booking details, use cookies and process data outside the EU under Google’s privacy policy. The legal basis for loading the optional calendar is your consent (Art. 6(1)(a) GDPR). Your choice is not stored; closing the booking dialog or reloading the page unloads the calendar until you choose to load it again. You can decline by using email instead, or visit the external booking page directly.
If you book a call, I receive and use the booking details (such as your name, email address and appointment time) to arrange the call and handle your request. The legal basis is Art. 6(1)(b) GDPR for contract-related enquiries and Art. 6(1)(f) GDPR otherwise, based on my legitimate interest in responding to enquiries. I delete these details when they are no longer needed, unless statutory retention obligations apply. You can contact me by email instead.
This website links to external websites, such as GitHub or LinkedIn. These are plain links: no data is transferred to these providers unless you click on them.
You have the right to:
To exercise these rights, please email me.
You also have the right to lodge a complaint with a data protection supervisory authority (Art. 77 GDPR). The authority responsible for me is the Landesbeauftragte für den Datenschutz Niedersachsen, Prinzenstraße 5, 30159 Hannover, Germany.