Rien Croonenborghs

Principal Engineer

NSW, Australia
rien@croonenborghs.net
https://www.linkedin.com/in/riencroonenborghs
https://github.com/riencroonenborghs

Personal Profile

Ruby on Rails engineer with a track record of building and shipping web applications from idea to production. I lead and mentor development teams while working closely with product managers, engineering leaders, and clients to keep technical projects aligned with business needs. I rely on pragmatic agile practices to ship reliable software on schedule, balancing deep technical execution with straightforward communication.

Technical Skills

Core & Frameworks
Ruby on Rails, JS (React, Vue), SQL, HTML/CSS
Cloud & Infrastructure
AWS, Heroku, RESTful APIs, CI/CD, Git, System Design
Databases & Search
PostgreSQL, MySQL, MongoDB, Elasticsearch
Testing & Practices
RSpec, Cypress, TDD, Agile (Scrum, Kanban, Shape Up)
Secondary Languages
Java, PHP, Perl, Bash, C/C++

Work Experience

2022 - Present
Senior Software Engineer & Principal Engineer
Hnry · Wellington, New Zealand & Sydney, Australia
  • Technical lead across Hnry’s Banking, Tax, and Platform teams, building financial infrastructure for 60,000+ sole traders in Australia and NZ.
  • Designed scalable banking integrations, automated tax workflows, and core platform services in a regulated fintech environment.
  • Mentored and led 4 engineers while partnering with product and engineering leaders to deliver complex projects on schedule.
2021 - 2022
Senior Software Engineer
Hatch Invest · Wellington, New Zealand
  • Led technical execution of Hatch’s virtual banking integration with FNZ, opening US stock market access to NZ retail investors.
  • Designed scalable transaction processing and banking workflows to meet strict fintech regulatory standards.
  • Partnered with product and engineering leaders to deliver core financial platform capabilities.
2014 - 2021
Senior Software Engineer & Technical Lead
ecoPortal · Auckland, New Zealand
  • Led 5 engineers building and scaling a SaaS platform for environmental, health, and safety compliance.
  • Modernized the tech stack by migrating the legacy frontend to a modern JS framework and removing outdated dependencies.
  • Reduced deployment cycles from 4 months to 3 weeks by setting up structured testing, issue tracking, and delivery workflows.
2010 - 2014
Senior Software Engineer
YouDo · Wellington, New Zealand
  • Developed B2B and B2C applications for YouDo to support New Zealand’s electricity retail market.
  • Built customer-facing and back-office systems designed to meet strict energy sector regulations.
  • Improved system stability and deployment pipelines across core retail energy services.
2001 - 2010
Earlier roles in software engineering available upon request.

Hobbies

Strength training. Fiddling with personal software projects. Photography. Juggling balls, rings, clubs and kendama. Hiking.