Senior Software Engineer

One of our valued clients are currently looking for a senior full stack engineer with 10 years (+) experience to join the team.

About the company

They are an early-stage B2B SaaS company, scaling a platform that leverages human expertise and modern AI tools to transform the way financial services are delivered. Their product is in advanced beta with live users, and they are preparing to scale to paid customers. They handle sensitive personal and financial data: trust, reliability, and stability matter as much as speed of iteration.

The role

We are looking for a senior, hands-on Full-Stack Engineer to join our small, highly experienced engineering team. You will work across the entire product, from Python services and APIs to React and TypeScript UI components. You will help deliver features end-to-end while raising technical standards across the codebase.

This role suits someone who enjoys taking ownership and who cares deeply about engineering quality. You will help shape good engineering practices in a small but rapidly scaling environment. You will collaborate closely with Product and the other engineers. You will contribute to architectural decisions and ensure the platform remains robust, secure and ready for scale. Your influence can grow as the company grows.

What you'll be doing

Build across the stack

• Deliver features end-to-end across Python backend and React and TypeScript frontend.
• Write clean, maintainable and well-tested code with clear API contracts.
• Build UI components and data-driven front-end features with strong TypeScript foundations.

Strengthen engineering standards

• Improve automated testing coverage across frontend and backend.
• Ensure CI and CD pipelines and quality gates support safe and frequent releases.
• Contribute to coding standards, documentation and review practices that lift the whole team.

Shape architecture and technical direction

• Participate in decisions around performance, scalability, tenancy and cost control.
• Contribute to a roadmap that may include evaluating alternative technologies. For example, Rust for performance-critical components.
• Apply security-by-design principles across authentication, authorisation, data handling and audit logging.

Help build a resilient and scalable platform

• Contribute to operational practices. For example, feature flags, safe rollbacks, incident handling, run-books, logging and monitoring.
• Improve performance across the stack. For example, SQL queries, React rendering and API throughput.
• Work closely with Product to scope work, plan release,s and make pragmatic build-versus-buy decisions.

What they're looking for:

Hard skills

• Python proficiency with any framework. FastAPI or Django are welcome.
• TypeScript expertise and strong React experience.
• Solid SQL experience. PostgreSQL is preferred but any advanced SQL background is welcome.
• Strong automated testing habits for unit, integration and end-to-end tests.
• Familiarity with GitHub workflows, CI and CD and standard developer tooling.
• Experience working in small teams and taking ownership of full product areas.

Mindset

• A self-starter mentality. You take ownership and enjoy solving complex technical challenges.
• Passion for creating high-quality, maintainable solutions that scale.
• Enthusiasm for working in a client-led environment where user feedback influences development.
• A collaborative approach. You thrive in cross-functional teams while working autonomously.
• High personal engineering standards. You lead by example rather than authority.

Nice to have

• Experience with Redis and Celery.
• Experience scaling multi-tenant SaaS applications.
• Experience with cloud platforms. (AWS, Google Cloud or Azure).
• Knowledge of containerisation (Docker or Kubernetes)
• Familiarity with SOC 2 readiness and security best practices.
• Experience with observability and monitoring.
• Background in fintech, lending or other regulated-data environments.
• Experience or interest in Rust or Go for performance-critical components.
• Experience designing or maintaining complex front-end state and data flows.

This is an opportunity to bring your skills and experience into a small leadership team where your opinions are heard and welcome. This is also a chance to be part of bringing a game changing product to life

This role is hybrid, 2-3 days in their offices at London Bridge

Salary ranges from £80,000 - £125,000 with attractive EMI share options