Full Stack Developer

Title: Full Stack Developer

Location: Hybrid (Warrington, United Kingdom)

Company: GTMaritime (Valstone Portfolio)

About the Company: GT Maritime provides mission-critical maritime cybersecurity and communications software to 2,000 companies and 16,000 vessels worldwide — roughly a quarter of the world's non-navy fleet. Based in Warrington, UK, GT Maritime operates as a focused, technically rigorous business with a strong culture of quality and long-term ownership. GT Maritime is part of the Valstone portfolio.

About Valstone: Valstone is an industrial software conglomerate that acquires and operates mission-critical software businesses across agriculture, logistics, food processing, bulk materials, and manufacturing. With 19 acquisitions completed across Canada, the USA, and the UK, Valstone takes a long-term, buy-and-hold approach — building businesses rather than exiting them. Valstone is part of the Valsef Group, a Montreal-based holding company. Sister entities include Valsoft (130+ acquisitions, $3B+ valuation), Permanent Corp, Valnet, and Valsef Capital.

Valstone at a Glance (Part of the Valsef Group)

• 19 acquisitions completed
• 4 core verticals
• Canada, USA and UK operations
• Buy and hold — no exit horizon
• $200M revenue target by 2026

About the Role: Reporting to the Head of Engineering, this Full Stack Developer role sits at the centre of GT Maritime's next phase of product development. The team is building the next generation of GT Maritime's platform — the layer where customers see what is happening across their entire fleet.

This hire will design and build partner API integrations across the cybersecurity stack — endpoint protection, network security, user awareness training, and SIEM/SOC tooling — and set the standard for test-driven development across the codebase. This is a hands-on, permanent role. You will not just build to spec — you will model TDD practice for the rest of the team through the code you write every day.

Responsibilities

Integration Development

• Design and build partner API integrations across GT Maritime's cybersecurity stack — endpoint protection, network security, user awareness training, and SIEM/SOC tooling.
• Write clean, modular, well-tested code following object-oriented design principles. Participate in code reviews and hold a high bar for what ships.
• Work within six-week Shape Up build cycles, collaborating with the Head of Engineering and Product on scoping, requirements, and effort estimation.
• Use AI-powered development tools (Claude Code, Cursor, GitHub Copilot) as standard instruments throughout the development workflow.

Test-Driven Development & Quality

• Champion and model TDD practice across the team — write tests first, every time, and make that standard infectious.
• Own test coverage, regression strategy, and acceptance criteria validation for integration code.
• Contribute to post-release reviews and continuous improvement of the delivery process.

Security

• Promote secure coding practices and conduct security-focused code reviews aligned with ISO 27001 certification.
• Support vulnerability identification and remediation as part of the everyday development workflow.
• Enforce least-privilege access and secure infrastructure configuration across the integration layer.

DevOps & Infrastructure Awareness

• Work alongside DevOps to understand and contribute to CI/CD pipelines, AWS resource management, and deployment practices.
• Support monitoring, logging, and alerting improvements that help the team detect and resolve issues faster.

Qualifications

• Full Stack Development — 3+ years of hands-on commercial experience building and shipping features in a SaaS environment. C# / .NET Core is the core backend language. Vue.js with Nuxt 3 is the front-end framework.
• Test-Driven Development — Writes tests first. Can coach peers. TDD is non-negotiable at GT Maritime.
• API Integration — Proven experience with REST, OAuth2, webhooks, rate limiting, and retry patterns. Has integrated with third-party commercial APIs at production scale.
• Security & Compliance — Working knowledge of application security fundamentals and ISO 27001 / secure-by-design principles.
• Cloud & DevOps — Familiar with AWS (EC2, RDS, Lambda, S3) and CI/CD pipelines. Comfortable with microservices and distributed processing architectures.
• AI-Assisted Development — Comfortable using AI-powered development tools as everyday instruments. Candidates who are resistant to AI-assisted development will not be a good fit for this team.
• Commercial AI API Experience — Has written production code calling Claude API, AWS Bedrock, OpenAI, or similar.

Who Fits This Role: GTMaritime is a lean, close-knit team. The culture runs on trust, ownership, and showing up for the work. This is the profile that fits.

Broad by Nature - Does not need a narrow lane to operate effectively. Comfortable moving between a feature build, a security review, and a release checklist in the same week.