Lead Software Engineer in Hampshire, Portsmouth

Aveni is redefining how financial institutions use AI. We build real, production-ready agentic systems that reshape how banks, advisers and financial services firms operate, replacing fragmented processes with intelligent, end-to-end workflows.

We have been recognised as Fintech of the Year for two consecutive years and awarded Best Specialist Technology Service at the Professional Adviser Awards 2025. Backed by leading investors including Puma Private Equity, and commercially supported by Lloyds Banking Group and Nationwide Building Society, we previously completed one of Scotland’s largest Series A rounds. Since then, we’ve continued to grow rapidly as adoption of AI in financial services accelerates, and we’re now scaling our engineering organisation to meet that demand.

Our engineering team includes experienced software engineers and PhD-level AI specialists, with strong ties to the University of Edinburgh, giving you access to exceptional expertise and opportunities for continuous learning as part of the day-to-day work.

The role involves being the most senior technical voice in one of our product squads, working as a technical co-leader alongside the Engineering Manager. You will own the squad's technical direction and engineering quality end to end, from architectural decision making and hands-on delivery, to mentoring engineers and shaping how we build across the organisation. This role demands genuine depth in AI, leading LLM powered feature development and setting the standard for how AI tooling amplifies the whole engineering process, combined with the full-stack and cloud-native skills to back it up.

What you’ll be doing:

• Setting technical direction for your squad, owning architectural decisions, managing technical risk, and representing the engineering perspective at our Architecture Review Board.
• Driving adoption of AI coding tools across the full SDLC, from planning and design through code review, testing, deployment and setting the bar for how the squad works.
• Delivering production grade code across the full stack: Node.js or Python backends, event-driven AWS architecture, and React where the squad needs it.
• Mentoring and growing engineers across AI and full-stack domains, through code reviews, design documents, and day-to-day pairing.
• Collaborating with platform teams to consume shared capabilities and contribute reusable patterns back, not building one-off solutions when a platform component will do.
• Ensuring everything we ship is compliant-by-design, auditable, and built to the standards expected of software in FCA regulated financial services.

What we’re looking for:

• A seasoned engineer with 10+ years of experience, including meaningful time building and operating AI/ML systems in production.
• Real technical leadership, having set direction, made architectural calls, mentored others, and influenced how a team builds, not just what it ships.
• Strong hands-on AI/LLM skills: prompt engineering, RAG, model evaluation and agent frameworks, with knowledge of how these work in production.
• Deep expertise in Node.js, with solid experience in the other; comfortable switching contexts depending on what the problem needs.
• Cloud-native development on AWS, including serverless, event-driven, Lambda, with an instinct for well designed, maintainable systems.
• A genuine curiosity about where AI is going and the judgment to separate signal from noise when recommending what to adopt.
• An instinct for building responsibly, caring about auditability, compliance, and the downstream impact of what you ship.

Why Aveni:

• You’ll work at the frontier of applied AI in a domain where it actually matters, helping financial services firms serve their clients better and meet growing regulatory obligations.
• AI-native engineering culture: we use AI tools seriously, across the full development process, and we’re always looking to push further.
• High impact from day one. As a Staff Engineer, your technical decisions will shape the product, the platform, and the engineers around you.
• A talented, collaborative team building something genuinely novel, with the backing, the architecture, and the proprietary models to do it properly.

Benefits at Aveni:

• Remote-first working across the UK.
• Work abroad policy for when you want a change of scenery.
• Co-working spaces available if you want an office buzz sometimes.
• 34 days holiday (including flexible bank holidays) and your birthday off.
• Company-wide off-sites.
• Optional Personal Development Plan.
• Flexible benefits platform: you choose the benefits that matter most to you.
• Protection essentials - Life Insurance, Income protection, critical illness cover, Pension (up to 5% matched employer contribution and optional increased contributions).
• Private health- and dental care for your peace of mind.
• Potential share options.
• Enhanced family leave.

Join Us in Making a Difference:

At Aveni, we believe that diversity drives innovation. We’ve built our business to ensure an inclusive workplace where everyone feels valued and empowered to contribute their best work. If you’re passionate about technology and its ability to drive positive change for the future of financial services, we’d love to hear from you. Even if you don’t meet 100% of requirements, we’d like to hear from you anyway if you believe you’d fit in. Apply now to join us on our mission to transform the financial services industry through AI.