Mark Castle

CTO & Senior Developer

Experienced technology leader combining entrepreneurial vision with deep technical expertise. Building startups, leading teams, and solving complex challenges with AI, distributed systems, and modern architecture.

London, UK • Open to Global Opportunities

About Me

I'm an experienced CTO and developer with a strong track record in building startups and technology businesses, combining an entrepreneurial spirit with a business-focused mindset.

Currently seeking challenging contract or permanent roles to leverage my expertise in AI, high-growth tech, and distributed systems. I'm passionate about helping companies thrive, comfortable in boardrooms or customer-facing roles, and committed to continuous learning and mentoring.

Open to global opportunities and ready to make an impact.

Experience

A journey of building, leading, and innovating

Recent Experience

Senior/Lead Developer — AI & Platform Engineering

Inovus Ltd

2020 – Present

Leading software engineering and AI strategy across the entire stack, building AI-powered connected medical simulations that train surgeons globally. Driving adoption of LLMs, machine learning, and intelligent automation across the product suite while leading and mentoring high-performing development teams.

  • ▸AI/ML & LLM integration — intelligent surgical training, automated assessment, and data-driven performance insights
  • ▸Polyglot development: .NET C#, TypeScript, Python, Unity3D
  • ▸Cloud-native architecture: Kubernetes, Terraform, AWS, IaC
  • ▸Led teams building AI-enhanced learning management and simulation platforms used worldwide

Lead Developer / Software Architect

Deloitte Digital, AI and Analytics

2019 – 2020

Lead developer and software architect designing and building large scale AI-driven traffic/rail simulations for government and public sector.

  • ▸Unity3D / C# / Serverless / Agile
  • ▸AWS / AI / Machine Learning
  • ▸Large-scale simulations for public sector

Founder

Captive Reality Ltd

2017 – Present

Freelance developer for companies such as Alpine Electronics, Asda/Walmart, designing and developing Virtual Reality, Augmented Reality, and Wearable applications.

  • ▸Unity3D, Xamarin Android/iOS, AWS, Serverless
  • ▸C#, Java, and more
  • ▸Client work across VR, AR, and wearable technologies

CTO

Vrtize Ltd

2016 – 2017

Founded a startup building a Virtual Reality Analytics and Advertising platform. Raised seed funding and built demo and MVP.

CEO

Secura Hosting Ltd

2001 – 2014

Built a cloud and managed services startup from the ground up to serve customers such as News International, Universal Pictures, ITV, thousands of UK Schools, Rocco Forte Hotels and more. Successfully sold to a private buyer in 2014.

Previous Experience

CTO/Founder

Shared Knowledge Ltd

1996 – 2001

High growth hosting and managed services startup. Raised GBP£1m seed investment.

IT Manager

Waterside Press

1995 – 1996

Managed IT infrastructure and systems.

Network Designer

Designtalk Ltd

1993 – 1995

Designed and implemented network solutions.

Skills & Expertise

Multilingual coder with strong technical and leadership capabilities

AI & Machine Learning

LLM Integration & Prompt Engineering
AI-Powered Product Development
Machine Learning
Intelligent Automation
AI Strategy & Adoption
Data-Driven Insights

Development & Architecture

C# & Unity3D
JavaScript (Node, React)
TypeScript
Python
Java & C++
Full Stack Development

Cloud & Infrastructure

AWS
Serverless Architecture
Kubernetes
Terraform & IaaS
Microservices
Big Data & Databases

Leadership & Innovation

AI & Machine Learning
Startup Development
MVP & Lean Methodology
Agile Management
Team Leadership
Problem Solving

Education

Teesside University

HND Information Technology

1992

Monks Walk School

O'Levels / A'Levels

1989

Beyond Work

Community Service

Elected Local Councillor – Welwyn Parish Council (2010 to present)

Chair of Finance, Vice Chair of Planning and Licensing Committee, Chair of local branch of Political Party (2025)

Personal Interests

VR meetup coordinator • Guitarist • Blues Harmonica • Game Development • Virtual Reality Development

Let's Connect

Open to challenging opportunities worldwide