Principal Software Engineer - Series A - AI FinTech Scale-Up

Principal Software Engineer - Up to £270k - Series A Scale-Up - Python, AWS

I’m working on a really interesting platform scaling hire for a fast-growing Series A AI/fintech company in London.

They’ve built a product that processes millions of sensitive financial documents for lenders, brokers, insurers and fintechs across the US and UK. The platform is already mission-critical for customers — but rapid growth means the backend now needs to evolve from “built for speed” to “built for scale.”

This role will work closely with the CTO and Head of Engineering and take real ownership of the core backend systems.

Principal Software Engineer - Up to £270k - Series A Scale-Up - Python, AWS

Key challenges include

• Designing backend abstractions so a small engineering team can ship quickly and safely
• Scaling multi-tenant infrastructure across enterprise customers with different security and SLA requirements
• Supporting high-throughput document processing and ML pipelines
• Strengthening security, reliability and compliance around sensitive financial data
• Scaling systems from millions → tens of millions of documents

💡 Ideal background:

• ~8+ years building and scaling backend systems
• Experience in high-growth B2B SaaS environments (Series A → C)
• Strong Python + cloud infrastructure experience
• Experience working with large volumes of regulated or sensitive data
• Hands-on IC mindset — someone who enjoys architecting and building
• A strong background in Computer Science, with a university degree from a top ranked Global University is essential

📍 London (hybrid)

💰 £190k – £270k + equity

Principal Software Engineer - Up to £270k - Series A Scale-Up - Python, AWS