Principal Engineer

e2b; Greater London; On-site; GBP 120,000 - 150,000; Full time

Job summary

Motorway is seeking a Principal Engineer to set technical direction across multiple product areas and evolve engineering practices. You will own the AWS relationship, influence architecture decisions, and drive AI-enabled software engineering initiatives.

You will represent Motorway externally and mentor senior engineers, shaping how teams deliver reliable, scalable services at pace.

Qualifications

• Ten years+ in software engineering, with Staff/Principal level experience.
• Track record of setting technical direction across teams.
• Strong AWS expertise: serverless, containers, networking, identity and data services at scale.
• Experience evaluating platforms against criteria and saying no when needed.
• Public speaking at conferences, summits or large forums.

Responsibilities

• Set technical strategy across multiple product areas and justify it to leadership with data.
• Identify cross-cutting architectural risks and resolve them at scale.
• Set engineering standards, architectural patterns, and documentation norms.
• Raise reliability, observability, and security standards across engineering, including AI-era threat models.
• Lead adoption of AI for software engineering and define best practices for LLMs and agents.

Skills

AWS expertise

Staff/Principal leadership

API & identity architecture

Observability & reliability

Public speaking

Tools

AWS

Kiro

Job description

ABOUT MOTORWAY

Motorway is the UK's largest online car-selling platform. We connect private sellers directly with over 8,000 dealers nationwide. Our online platform helps sellers achieve great prices for their cars while giving dealers fast, reliable access to the stock they want for their dealerships. Founded in 2017, our award-winning, technology-led approach has redefined the experience of selling a car. Motorway is backed by some of the world’s leading technology investors, having raised £143 million in Series C funding. This is a unique opportunity to join a fast-growing scale-up at a crucial phase of growth and help change an industry for the better.

ABOUT THE TEAM

Hi, I'm Mariot, I lead Engineering here at Motorway. We're around 70 engineers across product teams, building the marketplace and all services around that handles hundreds of vehicle transactions every day. We care about delivering value to the business, getting the architecture engineering sound, keeping the production bar high, and being early and deliberate about the technology we adopt. We have been early adopters of GenAI for software engineering, we've built a reputation for that, and we'd like to keep earning it. AI is enabling us to deliver faster at a much higher quality software while easing the maintenance of our existing services.

ABOUT THE ROLE

We're looking for a Principal Engineer to set technical direction and evolve engineering practices across Motorway, reporting to the Director of Engineering. This is a broad role: your remit spans multiple product areas and every engineering specialties, and your decisions will shape what we build, what we buy, and what we retire. You'll work with engineering leadership, product, and other functions stakeholders to continuously evolve our overall architecture and practices, and with our senior and staff engineers to turn that direction into working software. You will own our relationships with AWS on the engineering side, our main cloud provider. It's the foundation of our platform and one of our most important partnerships. In practice, we expect you to lead the following activities:

• Frequently meet AWS representatives getting access to latest services and features, share feedback on our usage and needs, and be an early tester and adopter of new services/
• Identify new services we could adopt to continuously improve our reliability and ability to build new services and features at pace for the business.
• Share internally good practices on software engineering at the edge and usage of AWS services, including continuously updating technical recommendations for humans and agents.

You’ll represent Motorway on stage at external events and in the wider engineering community, and you’ll set the standard for how engineers here present their work internally. You’ll also lead on our adoption of AI for software engineering. We give engineers access to the latest models through Kiro, and we want someone who can define what good looks like when domain depth, AI-enabled breadth, and rigorous evaluation all have to work together.

IN THIS ROLE, YOU WILL:

• Set technical strategy across multiple product areas, and make the commercial case for it to leadership with data rather than assertion
• Identify cross-cutting architectural risks and resolve them before they block us at scale
• Set engineering standards, architectural patterns, and documentation norms, including the writing precision that makes specs reliable inputs for both engineers and agent systems
• Raise the reliability, observability, and security bar across engineering: SLO philosophy, incident management standards, production readiness, and threat models that hold up in the AI era
• Be a force of innovation on AI for Software Engineering.: Monitor our LLM usage, latest models trial and evaluation, technical debt modernisation through AI agents.
• Develop staff engineers and technical leads, multiplying leadership capacity across the organisation
• Own the AWS relationship on the engineering side: architecture reviews with their solution architects, early access programmes, and the calls on which services we adopt, when, and at what cost
• Speak for Motorway in public, at AWS summits, conferences and meetups, and raise the bar internally for how engineers present their work to each other and to the business

ABOUT YOU

• Ten years or more in software engineering, with several of those spent operating at Staff or Principal level
• A track record of setting technical direction across several teams or product areas, where your decisions changed company outcomes
• Exceptional AWS expertise, both wide and deep. You've designed, operated and paid the bill for serverless, containers, networking, identity and data services at production scale, and you can hold your own in a room of AWS solution architects
• The judgement to evaluate new platforms and services against structured technical and commercial criteria, and to say no to the ones that don't earn their place
• Strong grounding in API and identity architecture: OAuth 2.0, OIDC, PKCE, JWT, and IAM patterns across multiple accounts
• Experience setting observability and reliability standards, and running incident practice that teams take seriously
• Comfort across the stack: you can read or write code in most languages, and follow a request from the browser through to the data layer
• A record of developing senior engineers into technical leaders, and of raising the hiring bar in your discipline
• Practical experience building with LLMs and agents in production, including how you evaluate them and keep their output trustworthy
• A strong public speaker with a track record to show us. You've presented at conferences, summits or large internal forums, and you can make a technical argument land with a room of engineers or a room of executives
• Writing that holds up under scrutiny: specs, architecture decision records, and strategy documents that others can act on without a m