César Vortmann
Senior Software Engineer Accommodations Team
Berlin, Germany
Summary
👤
Senior🎓
Top SchoolCésar Vortmann is a Senior Software Engineer with 15 years of experience building resilient, testable backend systems across travel, mobility, healthcare, and publishing domains. Based in Berlin, he has a track record of bootstrapping production services end-to-end—most recently leading Omio’s Accommodations stack, Payments-as-a-Service integrations, and a multi-agent conversational AI prototype. He champions engineering practices like TDD, Hexagonal Architecture, Trunk-Based Development and DORA metrics, and has driven measurable improvements such as raising test coverage from ~21% to ~96% and delivering revenue-generating pricing services. Comfortable across Elixir, Ruby, Java, Go and more, he blends hands-on coding with system design, RFC/ADR authorship and developer experience work. A pragmatic collaborator, he’s shipped cross-border projects and contributed to open-source healthcare tooling (OpenMRS) improving patient dashboard and visit handling. Notably, he pairs strong architectural discipline with experiments—introducing ArchUnitTS, Characterisation Tests and multi-agent function-calling prototypes to reduce risk and accelerate delivery.
15 years of coding experience
9 years of employment as a software developer
Bachelor, Computer Science, Bachelor, Computer Science at Universidade Federal de PelotasFederal University of Rio Grande do Sul
Github Skills (10)
javas10
openmrs10
java10
back-end-development9
javascript9
gsp8
junit8
jtest8
groovy8
front-end-development8
Programming languages (13)
Github contributions (5)
openmrs/openmrs-module-coreapps
Jun 2013 - Sep 2013
Provides apps for performing the common tasks
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:14 commits in 3 months
Contributions summary:César contributed to the OpenMRS Core Apps module, focusing on enhancements to the patient dashboard and retrospective visit features. Their work included modifying JavaScript and GSP files for UI updates, particularly regarding visit details and highlighting newly created visits. Furthermore, the user implemented changes in Java code, specifically within the RetrospectiveVisitFragmentController and associated tests, and updated visit date handling.
cvortmann/git-anonymize
Mar 2016 - Mar 2017
Contributions:5 commits, 1 PR, 2 pushes in 1 year
anonymizegit-commandcli
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