Principal Software Engineer Software · London, United Kingdom ·

Monolith AI; London; On-site; GBP 90,000 - 120,000; Full time

Job summary

A leading technology company in London is seeking a Principal Software Engineer to lead the architectural evolution of its platform. This role involves driving architectural initiatives, mentoring the engineering team, and ensuring the platform is AI-agentic ready. The ideal candidate has over 12 years of experience, strong Python skills, and expertise in distributed systems. This position offers opportunities for hands-on development and technical leadership.

Qualifications

• 12+ years of software engineering experience with at least 2 years in principal or staff engineering roles.
• Expert-level Python development skills with production experience at scale.
• Deep expertise in distributed systems architecture.

Responsibilities

• Drive the ongoing transition from monolithic to distributed architecture.
• Design and implement architecture to be AI-agentic ready.
• Mentor mid-level developers, elevating the technical capabilities of the entire team.

Skills

Python development

Distributed systems architecture

Kubernetes

Workflow orchestration tools

Cloud platforms (AWS, Azure)

Data processing frameworks

Job description

We're seeking a Principal Software Engineer to lead the architectural evolution of our platform as we scale to meet growing demand from the world's largest engineering companies. This is a hands-on technical leadership role where you'll drive critical architectural initiatives while mentoring our engineering team.

You'll be owning in conjunction with the VP Engineering the technical vision and execution of our platform's evolution to a more distributed architecture, making it AI-agentic ready for the next generation of AI applications.

Key Responsibilities

Technical Leadership & Architecture

• Drive the ongoing transition from monolithic to distributed architecture
• Design and implement architecture to be AI-agentic ready, enabling rapid deployment of AI products and MCP server integrations
• Own technical decisions balancing immediate business needs with long-term architectural goals

Hands-On Development

• Write production-quality Python code for critical platform components
• Build and optimize distributed compute services
• Implement reliable workflow orchestration patterns

Team Mentorship & Collaboration

• Mentor mid-level developers, elevating the technical capabilities of the entire team
• Establish engineering best practices and architectural patterns
• Collaborate with product and business stakeholders to translate requirements into technical solutions
• Guide technical decision-making and prioritization across the engineering organization
• Interview and onboard new engineers

Technical Requirements

Must-Have

• 12+ years of software engineering experience with at least 2 years in principal/staff engineering roles
• Expert-level Python development skills with production experience at scale
• Deep expertise in distributed systems architecture
• Strong Kubernetes experience with production workloads
• Hands-on experience with workflow orchestration tools (Temporal, Airflow, or similar)
• Cloud platform expertise (AWS required, Azure beneficial)
• Experience with data processing frameworks (Spark, Athena, or similar)
• Proven track record of leading architectural transformations in growing companies
• Excellence in technical communication and stakeholder management

What We're Looking For

• Technical Excellence: You write clean, maintainable code and design systems that scale
• Pragmatic Problem-Solver: You balance perfectionism with shipping, making smart trade-offs between short-term delivery and long-term goals
• Strong Leadership: You proactively identify problems and drive solutions forward
• Mentorship Mindset: You elevate others through knowledge sharing and patient guidance
• Ownership Mentality: You take full responsibility for outcomes and drive initiatives to completion
• Customer Obsession: You understand that our success is measured by our customers' success