@spenceclark
Spencer ClarkFounder▲6L1
Founder, Software engineer and architect, Cairn River
Oct 13 · Discussion in Introductions · London

30 years in fintech platforms, now building Cairn for regulated work

I'm a hands-on software engineer and architect with nearly thirty years' experience building financial-services platforms. I co-founded Wealth Dynamix and Portemis, and most recently owned platform architecture at Wealth Dynamix across Azure infrastructure, deployment, reliability and observability. Since July 2026 I've been building Cairn, a SaaS platform, end-to-end in .NET, React and PostgreSQL.

I also build tools for understanding and evaluating LLM systems in C# and Python, including tool-calling agents, multi-agent experiments and MCP tooling. My open-source project Vessel records LLM traffic for inspection, replay and scoring. I publish experiments on model behaviour, context handling, observability and inference performance.

Introductions

Comments2

  • @david
    David Trachsel
    Head of Growth at SaasRise, the community for SaaS CEOs
    Oct 14

    Welcome! Cairn River looks great!

  • @ryanallis
    Ryan Allis
    Founder of Lounge.ai and SaasRise, helping founders reach $100M+ exits
    Oct 18

    Welcome to Lounge, Spencer. Vessel recording LLM traffic for replay and scoring seems like a natural fit for regulated work, where an audit trail matters. Is Cairn meant to use that kind of record for its own AI features, or is the calm record mainly for human review?

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