hello world
Cosmin Onea
Software Consultant, Software Architect, Founder
Twenty-five years building software, from payment authorisation pipelines and multi-tenant SaaS platforms to agentic delivery pipelines. I turn complex domains into architectures teams can actually maintain.
About
who I am
I'm a software consultant, architect and founder with over 25 years of experience building and running software systems. I've led engineering teams at Tesco, Springer Nature, SiriusXM, Pret A Manger and Kingfisher — across payments, e-commerce, publishing and media.
I specialise in scrutinising requirements until the actual problem shows itself, then turning complex domains into architectures a team can maintain. That has meant a PCI-regulated payment authorisation and settlement pipeline at Tesco, deliberately boring technology at Springer Nature where Spring, Hibernate and React were all off the table, and most recently an agentic SDLC pipeline at Kingfisher with humans kept in the loop.
As a founder, I co-founded Contingent Technologies, raising venture capital and bootstrapping the team, and I now run QontaHub, a modern accounting practice management product.
Experience
career.map()
Equal Experts
LondonAssociate Consultant providing software engineering services to clients including Tesco, Informa, Springer Nature, SiriusXM, Pret A Manger and Kingfisher.
client engagements
Kingfisher
LondonBuilt Kingfisher's agentic SDLC pipeline, with humans in the loop: user story creation and verification skills, security reviews, SRE reviews, and an agentic execution pipeline running from JIRA to GitLab.
SiriusXM
New YorkSpringer Nature
LondonTech lead and architect for a business-to-business e-commerce platform, working closely with business stakeholders to plan, architect, design and implement it. Springer Nature Engineering has a policy of using boring technology rather than "magic" technology: frameworks such as Spring and Hibernate on the backend, and React, Angular and Vue on the frontend, were strongly discouraged. I led the team back to basics — simple Kotlin libraries such as http4k and jdbi on the backend, Express and handlebars on the frontend — while keeping the team productive and achieving the business and product goals.
Pret A Manger
LondonLed the web team and worked with other architects to set the architecture and standards across Pret's Digital Platform. Designed the content management system for Pret's international websites, working with Contentful architects to solve internationalisation problems we identified. Set up the content type migration pipeline so any change in content structure goes through a CI pipeline. Designed and implemented the new digital publishing platform used to launch new franchise partners around the world in minutes instead of weeks or months. Improved the performance of existing sites by 10 to 20 times, which improved both user experience and infrastructure cost.
Tesco
Farringdon, LondonBuilt the next generation payments system at Tesco. Designed and implemented the payment authorisation and settlement pipeline for both Tesco Stores PEDs (Pin Entry Devices) and e-commerce payments. Bridged the gap between the infrastructure and development teams to build and evolve the data centre production environment under PCI rules and regulation.
Informa
St Paul's, LondonDesigned and implemented Informa's Agri Platform, an online publishing platform deployed on AWS and used to publish global agricultural reports and data. Worked closely with business stakeholders to understand and implement requirements, and coordinated with Enterprise IT on VPC security policies and penetration testing strategy.
Co-founded, raised venture capital and bootstrapped the team. Led the product team while keeping a focus on software engineering, as Senior Software Engineer and Architect.
Earlier career, 2001 – 2015 (8 roles)
JUST EAT
St Paul's, LondonTech lead for the call centre apps, involved in the design and implementation of various business support apps. Improved the Just Eat cloud-to-restaurant infrastructure to handle millions of orders every month across more than 40,000 partner restaurants. Ran the book club, a weekly group of software engineers exploring programming languages and techniques for building software better.
1E
Ealing, LondonTech lead across three products. Shopping: brought the legacy app up to date by progressively introducing HTML5 and CSS3, and changed how the team engaged with the business by focusing on desired application behaviour based on production metrics. ActiveEfficiency: bootstrapped the team and built the company's first Azure-based multi-tenant SaaS platform, including identity federation for customer single sign-on. Workspace: a virtual environment delivery service enabling people to use their own devices at work without compromising security — introduced coding standards, client auto-updates and a continuous delivery pipeline, and drove TDD/BDD refactoring of the C++ client so the whole team could support it.
British Standards Institution
LondonTech lead of the team that delivered Entropy Software, an enterprise governance, risk and compliance system. Worked with product management and other stakeholders to translate business requirements into stories, and was responsible for the architecture and design of a cloud platform used to deliver BSI services. Used advanced debugging skills to diagnose and improve legacy products, saving a significant amount of customer resources.
Q2Q
LancasterPrimetel
Limassol, CyprusAmdocs
Limassol, CyprusInfoworld
Bucharest, RomaniaInteramerican
Bucharest, RomaniaVentures
founder.projects()
QontaHub ↗
Founder and CEO of QontaHub, the modern Accounting Practice Management product.
Contingent Technologies
Co-founded, raised venture capital and bootstrapped the team. Led the product team while keeping a focus on software engineering, as Senior Software Engineer and Architect.
- ▸ Co-founded the company and raised venture capital
- ▸ Bootstrapped the engineering team
- ▸ Led the product team while staying hands-on in engineering
Skills
stack.groupBy(discipline)
agentic engineering
disciplines
practices
cloud
ci/cd
backend
messaging
frontend
identity
containers
sql
nosql
payments
Achievements
selected work
- Built the next generation payments platform for Tesco Stores.
- Finalist in the UK IT Industry Awards 2017 (Digital Project of the Year) for creating IEG Vantage, Informa's agribusiness intelligence platform.
- Active speaker at meetups on Domain-Driven Design, AWS Lambda, Azure Functions and Lean Software Development.
- As Tech Lead at Just Eat, designed and implemented many of the call centre applications with a focus on both usability and security.
- Bootstrapped and implemented ActiveEfficiency, a multi-tenant software as a service platform on Windows Azure used to deliver 1E's services over the web.
- Led 1E Workspace, a virtual environment delivery service that enables people to use their own devices at work without compromising on security.
Education
qualifications
BSc Cybernetics, Statistics and Computer Science
Dissertation: Using Web Services for business to business integration
Microsoft Certified Professional Developer, .NET 4
outside work
Contact
get in touch
Available for consulting engagements and always happy to talk about architecture, domain-driven design or payments. Email is the fastest route.