Claudio Jolowicz Email & Phone Number

Remote

Berlin, Germany

Keeping up with the Python ecosystem can be daunting. Its developer tooling doesn’t provide the out-of-the-box experience native to languages like Rust and Go. When it comes to long-term project maintenance or collaborating with others, every Python project faces the same problem: how to build reliable workflows beyond local development while staying in sync with the evolving ecosystem.With this hands-on guide, Python developers will learn how to forge the moving parts of a Python project into an easy-to-use toolchain, using state-of-the-art tools including Poetry, Nox, pytest, mypy, pre-commit, Black, Ruff, uv, Rye, Hatch, and more. Author Claudio Jolowicz shows you how to create robust Python project structures complete with unit tests, static analysis, code formatting, and type checking.

Berlin, Germany

Responsible for Cyren's email security products. Designed, implemented, and maintained high-performance C++ libraries, data-intensive backend services, the cross-platform developer SDK, and on-prem products.• Designed an email fingerprinting algorithm using similarity hashing over abstract syntax trees, based on original research. It accounted for 25% of spam classifications of Cyren’s anti-spam products (500+ million emails/month), directly impacting customers of cloud and on-prem services.• Designed and implemented the high-performance C++ production code for the same fingerprinting algorithm, using static polymorphism to build an expressive and maintainable DSL for parser combinators with zero overhead. Implemented the earlier Python prototype used for measurements during research.• Led the redesign of a legacy distributed service with loads up to 50,000 QPS. Involved stakeholders from four internal teams and five large ISP customers, building consensus for incremental change using a service facade.• Mentored developers across teams on best practices in C++ and Python development, software design, dependency management, continuous integration and delivery, and other topics.• Refactored Cyren’s C++ anti-spam SDK to expose internal APIs for analyst tooling, improving maintainability and performance (100-200x).• Identified the fragmentation of a C++ codebase over 50+ Git repositories as a barrier to modern CI practices. Solved it by migrating the codebase to a monorepo in a lossless and reproducible way (1.1 million SLOC).• Investigated scaling issues in the build infrastructure for the C++ monorepo. Migrated build environments from VMs to lightweight containers. Successfully advocated dropping support for obsolete platforms.• Rewrote the build, test, and release infrastructure for the C++ monorepo using Python, CMake, GitLab CI, Docker, Artifactory. Improved developer productivity and build reliability.

Berlin, Germany

• Co-authored an async I/O implementation in C++ with an event loop and network stack (TCP, UDP, TLS, DNS). It played a key role in delivering a 20-fold performance increase to Cyren’s anti-spam product.• Designed and implemented high-performance C++ libraries for Internet Standard protocols (SMTP, HTTP, SNMP), used in four highly available cloud services and two cross-platform on-premise products.• Top contributor for the C++ source libraries (37% SLOC), providing support for threading, memory management, filesystem access, networking, parsing, logging, data structures, POSIX and Windows OS facilities, and more.• Top contributor for the C++ anti-spam SDK and SMTP service (50% SLOC). The latter’s system design served as a model for other server applications in the company.

Multi-instrumentalist, arranger, and composer. Collaborated with over 100 artists and toured across 24 countries. Appeared at Roskilde Festival (130K visitors) and on the Morgenmagazin TV show (740K audience).

Berlin, Germany

Research in the field of Artificial Intelligence and Law under an EU research project (IMPACT/FP7), using the Web Ontology Language (OWL-DL) and a Clojure-based rule engine for modeling human argumentation. Described how ontology-based rule systems can be used to help companies identify and fulfill reporting requirements.

London, England, United Kingdom

Responsible for the backend architecture of a real estate search engine (Python). Designed and implemented data extraction algorithms in Python using Machine Learning and web technologies. Helped the search engine scale quickly to index property listings across the UK and South Africa, as the startup successfully closed its first round of funding.

Master’S Degree, Computing Science, Distinction

Thesis: Delegation, Representation, and Declarations. Designed a modal logic to represent declarations in multi-agent systems.

1St State Examination In Law, Distinction (11.06)