Staff Software Engineer focused on building fast, reliable and easy to reason about systems in complex, high-stakes domains. Across startups and scaling unicorns, I have combined strong product thinking, effective collaboration and deep systems expertise in Elixir, Ruby and SQL to help teams deliver quickly while maintaining long-term sustainability.
I improve how teams build software by removing obstacles, fostering a culture of collaboration and filling the gaps. I increase team effectiveness through mentoring, tooling, system design and clear communication. I collaborate closely with engineers and product to build systems that are both technically sound and address user needs.
I'm an active contributor to the developer community through conference talks, writing and open source work.
Key Contributions
- Created benchee, shaping how performance benchmarking is done across the BEAM ecosystem (1.5k+ stars on GitHub, ~10M downloads)
- Built a high-performance proxy serving ~84M requests/day (~2000 RPS) on a single 4-core node with a strict 100ms latency budget enabling a new business use case
- Senior Staff Engineer collaborating with ~100 engineers during hyper-growth at Remote through architecture guidance and cross-team leadership
- Keynote speaker at Code BEAM EU with the talk "Going Staff"
- Led incident response & analysis for critical payroll, financial and logistics systems
Together.ai
(~250 employees)
07/2025 — now
Improving a critical central service (Elixir, PostgreSQL) focused on identity & collaboration while maintaining various clients (TypeScript, Go, Python), helping the company move to an improved model.
- Took ownership of a critical backend service within weeks, formalized architecture & API design, reducing reliance on tribal knowledge while improving the effectiveness of AI agents
- Led cross-team Blocking & Banning initiative, aligning product and engineering, clarifying system dependencies to help us remove a call to Redis from a critical path & allow new usage patterns
- Improved reliability and observability by integrating gRPC error tracking, adding missing integration tests to critical paths, correcting metric inaccuracies & improving performance - now we know our P95 response time is sub millisecond
Screenverse
(~40 employees)
06/2024 — 06/2025
Worked in programmatic digital out of home advertisement using Elixir to ship performant & reliable software.
- Designed & implemented a high-performance caching proxy with a strict 100ms end-to-end latency budget handling ~84M requests/day (~2000 RPS peak) on a single 4-core node using Elixir, GenServer, ETS & Plug
- Used Rust to efficiently parse & transform XML responses as well as adding Redis as more permanent cache to support follow-up requests with a longer lifetime
- Contributed improvements to libraries across our networking stack (Req, finch, mint)
- Pushed initiatives like developer learning, standardization, test coverage & reducing error fatigue
Remote
(~150 → 1100 employees)
04/2021 — 10/2023
Worked on a big Elixir & Phoenix monolith in HR-tech with a focus on the payments domain, automating processes to ensure safe, quick & reliable payments of millions while improving processes and technology company wide.
- Acted as the most senior engineering individual for long periods during hyper growth, advising teams, reviewing designs, facilitating cross-team decisions & intervening in high-risk changes and situations
- Drove company-wide engineering process improvements (RFC process, branching model)
- Introduced Background Job System (Oban) to guarantee reliable asynchronous processing in a large Phoenix monolith
- Prevented high-risk architectural coupling by redirecting a planned job board feature out of the HRIS monolith into a separate service after system interaction analysis
- Architected & Implemented features to help our payments efficiency and product offering: adding more payment providers, automatic invoice payments, bank integration via PAIN XML to automate payments, enable direct debit for huge sums & allowing non local currencies
- Led incident response for multiple production failures involving payroll and financial processing, coordinating mitigation and post-mortems
- Advocated for hiring non Elixir engineers, set up a training camp and mentored to help them succeed
- Participated in more than 100 interviews during hyper-growth, trained others on interviewing and code challenge reviewing
Shopify
(~8000 employees)
08/2020 — 03/2021
Engineering Lead for a team working in Ruby on Rails on topics ranging from local market adaptation, to legal and delivery promise in the e-commerce field.
- Identified systemic issues in team structure, knowledge sharing and domain ownership during rapid organizational changes, providing detailed analysis and recommendations adopted by leadership
- Implemented performance improvements in SimpleCov to support large-scale parallel CI workloads
Self-employed
08/2019 — 07/2020
Consulting, Teaching and Development.
- Helped a company develop their first Elixir project, introducing the technology to the team
- Loadtested a Rails ecommerce system leading to 100x more concurrent checkouts with fewer servers
- Worked on a complex microservice metrics visualization application in Ruby & NodeJS
- Open Source work on the code coverage tool SimpleCov sponsored by Ruby Together
- Consulted on the design, architecture & implementation of an open source project, including implementation
Liefery
(~50 → 150 employees)
01/2017 — 02/2019
Led a product department of 15 together with the CTO, handling the day-to-day needs of the team. Built and maintained applications to track shipments, plan tours and manage all required logistics data in Ruby on Rails, Elixir and Phoenix as well as JavaScript (AngularJS, React).
- Helped, mentored & guided colleagues through 1:1s, pairing sessions, pull request reviews and knowledge sharing sessions
- Ran retrospective and iteration meetings, continuously adapting and improving processes
- Architected and designed features with the squads
- Served as interim-CTO during a sabbatical
- Monitored application performance and fixed performance problems
- Screened and interviewed candidates
- Gathered issues from operations and partners to define and triage solutions
- Ran integration projects with customers to onboard them as quickly as possible
bitcrowd
(~10 employees)
01/2015 — 10/2016
Built various applications with Ruby on Rails, AngularJS & React in an agency setting, prioritizing customer collaboration and delivery. Introduced practices such as retrospectives, Continuous Integration and mentored juniors.
Self-employed
05/2013 — 09/2018
Occasional projects related to teaching programming, such as an introductory course to Ruby on Rails at Humboldt-University Berlin.
Open Source
08/2011 — current
Long-time open source contributor, maintainer and creator of widely used developer tools with significant ecosystem impact.
- Created benchee, a powerful and extensible benchmarking library widely used in the BEAM ecosystem (1.5k+ GitHub stars, ~10M downloads) for statistically robust benchmarking, used by Elixir-core among others
- Maintained simplecov, a widely used code coverage library (450M+ downloads)
- Maintained Shoes, an easy to use GUI toolkit written in JRuby (also part of Google Summer of Code)
Community & Conferences
05/2012 — current
I've been an active member of the programming community for more than a decade. I have spoken at conferences such as Øredev, Lambdadays, Polyconf and Full Stack Fest.
- In 2024 I keynoted Code BEAM EU with "Going Staff"
- My talks cover a wide range, from Benchmarking to "Functioning Among Humans"
- I've been the main organizer of the Ruby User Group Berlin since 2012, a monthly meetup with between 20 and 120 attendees
- Long-time Rails Girls coach, giving introductions as well as mentoring a group from learning to program all the way through being senior engineers
- Head organizer JRubyConf 2015 & organizer eurucamp 2015, was a member of the program committee of GOTO Berlin 2014
- Co-created the Berlin Code of Conduct to ensure and promote a safe environment
Hasso Plattner Institute / Blekinge Institute of Technology (Erasmus)
2008 — 2014
Final grade: 1.2 (A), Specialization in Software Architecture, Internet Security, agile & globally distributed software development.
Languages & Frameworks
- Elixir & Phoenix
- Ruby & Rails
- SQL & PostgreSQL
- JavaScript & TypeScript
Systems Engineering
- High-throughput backend systems
- Performance benchmarking & profiling
- Observability & Reliability
- Distributed Systems
Architecture
- API Design (REST / gRPC)
- Monoliths and Microservices
- Domain modeling & Database Design
Leadership
- Staff-level technical leadership
- Incident response & post-mortems
- Async work, scaling organizations & processes
- Hiring & Mentoring