William John Warne
Software Engineer | Fractional CTO | Founder
Seeking long-term ownership in technical leadership roles focused on design and delivery—solution and system design, practices, and tooling. Companies eager to use AI-augmented development, context engineering, spec-driven development, and agentic workflows. I work well autonomously or embedded into teams when I can put my experience to use. I seek environments where I can learn from strong engineers, value direct feedback, and contribute alongside experienced peers—I don't assume I have all the answers. Remote work only. I'm relocating to Mafra, Portugal in June.
Background
6+ years software engineering experience; more recently in consulting, directly involved in 15+ ventures from idea to launch across medical, trading, and AI SaaS. Having honed my skills in both rapid short term projects and long term sustained projects, I understand the consequences of technical decisions and how to manage these, while having the opportunity to iteratively refine approaches based on what worked and what didn't. I focus on solution/system design and delivery across the stack: design, backend, infrastructure, and developer experience. Systematic design and delivery; modern tooling and AI-augmented workflows extend that. Combining my experience and modern tooling to improve quality, alignment, and delivery speed.
I've partnered with founders, clients, and teams to build systems that ship and scale, and I care about clear communication and alignment.
Experience
FOUNDER
ZEBRA LABS LTD · LONDON, UK
Jan 2024 – Present · 1 yr 2 mo
- Redesigned and rebuilt high-throughput AI system for 100k+ users (Luma Learn) in 2 months with sub-1 second response times.
- Designed production-ready backend systems for AI SaaS platforms scaling for enterprise (Clairo AI).
- Built maritime platform ecosystem transforming vessel management across multiple integrated apps (OneSea).
- Applied resilience patterns (circuit breakers, resource segregation) and observability to avoid cascading failures when services hit limits.
- Established AI-enhanced development workflows and operational processes increasing development speed and quality.
- Led end-to-end technical delivery for Luma Learn, Clairo AI, and OneSea across healthcare, trading, maritime, and AI sectors.
- Advised on post-handover team structure and tooling: generalist technical lead with specialist niches so domain experts could leverage workflows effectively.
- Resolved ownership and data-quality misalignment on ECI platform via DDD-style mapping of responsibilities and dependencies across sales and systems teams.
Vercel · AWS · Docker · React · Next.js · TypeScript · Redis · Supabase · Cursor · Claude · Fly.io · FastAPI · Python · PostgreSQL · SQLAlchemy · Alembic · Drizzle · WhatsApp Cloud API
FULL STACK ENGINEER
SPHERE · LONDON, UK
Feb 2022 – Jun 2024 · 2 yr 5 mo
- Evolved trading platform: built custom ML model integrations for curve pricing and refactored trade and price distribution from user-based to action-based event classification.
- Drove design standardisation and clearer technical direction to address issues from lacking a consistent architectural north star.
- Designed and implemented curve integration and display vertical with focus on performance and system architecture.
C# · .NET · Entity Framework · Azure · React · TypeScript · Docker
DEVELOPER
DOCTORLY · BERLIN, GERMANY
Nov 2021 – Feb 2022 · 4 mo
- Developed backend API system using Domain-Driven Design for highly critical healthcare platform.
- Applied strict DDD and dependency-direction practices with the team; achieved near-full test coverage and very few production bugs and incidents.
C# · .NET · MediatR · SendGrid · Entity Framework · AWS · JavaScript · SQL Server · MySQL · PostgreSQL · Docker · React · Sentry
DEVELOPER
THE DELTA STUDIO · CAPE TOWN, SOUTH AFRICA
Dec 2019 – Feb 2022 · 2 yr 3 mo
- Backend development for founders and corporates spinning out new ventures: corporate reward platforms, social platforms, transport and logistics systems.
- Designed and developed solutions using headless architecture, Domain-Driven Design, monoliths, and microservices.
- Refactored codebases where unclear structure and lack of dependency rules had led to circular dependencies and maintainability issues.
- Saw impact of inadequate monitoring, logging, and alerts on reliability; applied those lessons to later projects.
- Progressed from junior developer to leading software projects and refining operational processes (project management, development, quality assurance).
C# · .NET · MediatR · SendGrid · Entity Framework · AWS · JavaScript · SQL Server · MySQL · PostgreSQL · Docker · React · Sentry
Personal Life
I enjoy the outdoors, fitness, and working with my hands—whether that's hiking, surfing, or building surfboards and apps. I also enjoy furthering my knowledge on religion, AI automation, psychology, and whatever else catches my interest. I have a close connection with my family and faith. I'm relocating to Mafra, Portugal in June with my fiance.
Contact
- wjohnwarne@gmail.com
- Phone
- +447508559737
- Address
- Remote · Relocating to Portugal
About Me
- DOB
- 15 Jul 1996
- Nationality
- South African & British
- Marital Status
- Single (Engaged)
- Languages
- English
- Religion
- Christian
Skills
- • Python | FastAPI · 4y
- • JS/TS | NextJS | React · 5y
- • C# | .Net · 5y
- • PostgreSQL · 5y
- • Redis · 3y
- • Domain-Driven Design · 5y
- • System & Solutions Design · 5y
- • Monolith | Headless Architecture · 4y
- • Microservices · 4y
- • Security & Policy Review · 3y
- • Cursor | VS Code · 2y
- • OpenAI | Anthropic | Claude · 2y
- • n8n | Workflow automation · 1y
- • AWS | Azure | Vercel · 5y
- • Supabase | Fly.io · 3y
- • Docker · 5y
- • K9 | Playwright | Jest · 2y
- • Git | GitHub | GitHub Actions · 6y
Core Competencies
- • System Architecture & Design
- • Pragmatic Solution Development
- • Fractional CTO Services
- • Modern tooling & AI-augmented workflows
- • Production reliability & readiness
Education
BACHELOR OF ENGINEERING (MECHANICAL)
UNIVERSITY OF CAPE TOWN
2015 – 2019
Industries
- • Healthcare
- • Trading & energy
- • Maritime
- • AI / SaaS
- • Coaching & education
- • Education
- • Social platforms
Recent Achievements
Jan 2024 – Present
- • Redesigned and rebuilt high-throughput system for 100k+ users (Luma Learn) in 2 months with sub-3 second response times.
- • Designed production-ready backend systems for AI SaaS platforms scaling for enterprise (Clairo AI).
- • Built maritime platform ecosystem transforming vessel management across multiple integrated apps (OneSea).
- • Applied resilience patterns (circuit breakers, resource segregation) and observability to avoid cascading failures when services hit limits.
- • Established AI-augmented workflows and tooling for the team.
Work History
Jan 2024 – Present
Zebra Labs LTD
Founder
Feb 2022 – Jun 2024
Sphere
Full stack engineer
Nov 2021 – Feb 2022
Doctorly
Developer
Dec 2019 – Feb 2022
The Delta Studio
Developer
Hobbies / Interests
- • Muay Thai Boxing
- • Surfing
- • Road/Trail Running
- • Weightlifting
- • Reading