Paul Johnson

Software development, architecture, technical leadership and QA. Zürich, Switzerland.

https://www.pjcj.net  ·  paul@pjcj.net  ·  LinkedIn  ·  GitHub  ·  MetaCPAN

Summary

Software engineer and technical leader with 30+ years’ experience across startups and global enterprises (UBS, Swiss Re, Swisscom, Perceptyx). Co-founder of TransEDA, which pioneered code coverage in the EDA market and IPO’d on the London Stock Exchange. Author of Devel::Cover, the standard code coverage tool for Perl, and creator of CPANCover. Known for measurable performance and reliability work, building and mentoring engineering teams, and widely-used open-source tooling. Native English speaker, with professional German.

Experience

2020 - present: Perceptyx

Employee experience and engagement survey platform. Perl, Go, MySQL, Redis, FreeBSD.

• Led two successive engineering teams (7 then 4) delivering work across the survey core and two major new subsystems.
• Designed and led delivery of two new Go services: a dashboard fronting all available surveys, and a job-dependency system that triggers survey invitations when configurable business criteria are met.
• Profiled and optimised a set of 90 batch jobs, cutting runtimes from over 3 hours to 4 minutes, and brought API endpoint response times down from 4 seconds to 0.3 seconds.
• Eliminated hour-long CI queues by optimising the test suite, restoring fast developer feedback.
• Modernised core subsystems: database connections, logging, background jobs and settings.
• Handled production incident response for systems I worked on: diagnosis, immediate recovery and long-term remediation.
• Improved unit and end-to-end testing, and code coverage across the codebase; built developer tooling in Bash and Perl to speed up day-to-day engineering.

2016 - 2019: SwissSign AG

Swiss certificate authority, Zürich. Perl, C, MySQL, Linux, Docker.

• Two-engineer team with end-to-end responsibility for the CA platform.
• Designed and built a queue and background job system for asynchronous workloads.
• Designed and built DNS-based domain validation and CAA record checking required for certificate issuance.
• Maintained and extended the CA software, keeping it compliant with current PKI root programme requirements.
• Modernised legacy codebases and implemented new subsystems for database access and logging.
• Migrated the codebase from SVN to git, unblocking an overdue release.

2013 - 2015: Genscape, Inc.

EPSI (European Power System Insight): real-time analytics for European power traders and analysts. Originally Energy Fundamentals GmbH, Zürich, acquired by Genscape in 2014. Perl, C, MySQL, Linux.

• Two-engineer team with end-to-end responsibility for EPSI, covering the interconnected European power market - plant-level data, market prices, interconnection flows and scenario analysis.
• Worked across the stack, from hardware provisioning and data ingestion through market modelling to low-level profiling and optimisation.

2010 - 2012: Swiss Re, Swisscom IT Services

• Swiss Re - Programme QA Manager. QA responsibility across a programme of financial projects, each with its own QA lead. Defined QA strategy across the project lifecycle, established processes combining company policy, regulatory requirements and industry best practices, and supported projects in adopting them. Liaison between projects and testing, operational readiness, security and audit functions. Analysed QA gaps and drove improvements.
• Swisscom IT Services - Website Manager. Two-engineer team with technical responsibility for news websites owned by Tamedia, one of Switzerland’s largest media groups. Designed and built the iPad registration website and web services backing the Tages-Anzeiger iPad app.

2001 - 2009: UBS

Swiss bank, Zürich. Contractor. Perl, Groovy, Python, ksh, Oracle, Solaris.

2004 - 2009: Technical lead, cash management integration. Integrated an externally developed cash management product into the standard bank environment.

• System architecture and technical direction.
• Designed and built interfaces to 14 subsystems including databases, messaging, web front-end, logging, packaging and monitoring.
• Designed and implemented the high availability backup solution.
• Production incident diagnosis and recovery.
• Built automated testing, monitoring, reporting and support tools.
• Functional and monitoring improvements cut production downtime by over 90%.
• Redesigned the management information pipeline: daily SQL workload dropped from over 40 hours to 15 minutes.

2001 - 2004: Credit systems programme. Led integration and production testing for a large programme unifying credit systems across internal groups and external companies.

• Coordinated multiple QA teams, drove process improvements, and introduced automated test suites and monitoring tooling.
• Raised testing-system availability from ~75% to over 95%, improving downstream production stability.

1992 - 2000: TransEDA Ltd

Pioneered code coverage in the EDA (Electronic Design Automation) market; IPO’d on the London Stock Exchange. C++, Perl, Ada, Unix.

• Co-founder. Led an engineering team of up to 7, within a ~15-strong engineering organisation. Managed subcontractors and recruitment.
• Led all aspects of product development: planning, design, implementation, testing, release and maintenance.
• Designed and built large subsystems: code coverage tools, a VHDL front end to synthesis, synthesis algorithms, and a technology mapper.
• Created the QA infrastructure and the cross-platform build, test and licence generation systems; ported products across Solaris, HP/UX, AIX, Linux, VMS and Windows.

Open Source

• Active member of the Perl community since 1999. Numerous modules on CPAN and patches to the Perl core and core modules, including a core patch reducing memory usage by up to 2.5%. Annual attendee at the Perl Toolchain Summit.
• Devel::Cover - the code coverage module for Perl. Used by CPAN module authors for release QA and in production engineering at large enterprises including UBS and Morgan Stanley; part of the Phalanx QA project for Perl.
• CPANCover - continuously measures and publishes test coverage for CPAN modules, giving the Perl ecosystem a single view of code-coverage health.
• Led The Perl Foundation in Google Code-in 2011/2012: directed 50 mentors across 300+ student tasks.
• SureSpell - a Perl/Tk program helping dyslexic children improve reading and spelling using audio and visual cues; used in a successful teaching programme on Linux and Windows. Best paper, European Perl Conference 2005.
• Regular speaker at European Perl conferences; full list of papers online.

Education

• M.Eng. (Software Engineering), Class II(1) Hons. Imperial College London.

Technical

• Languages: Perl, Go, C++, Bash, SQL; familiar with many others.
• Backend & systems: service design, profiling and optimisation, databases, messaging and queues, logging and observability, high availability, production incident response.
• Web: modern JavaScript, CSS and HTML on the client; Plack, Dancer, Catalyst, Apache and nginx on the server; Playwright and Selenium for browser-level testing.
• Ops & sysadmin: Linux and many Unix dialects, containerisation (Docker), CI/CD pipelines, git and build systems; working knowledge of AWS, Kubernetes and DataDog.
• AI-assisted development: proficient with modern AI coding tools (Claude Code and similar) for implementation, refactoring, code review and research; mindful of their limits and how to verify output.
• Quality: unit, integration and end-to-end testing; code coverage; debuggers, memory checkers and profilers; commercial and open-source QA tooling.