Principal Engineer

Motorway; Greater London; Hybrid; GBP 120,000 - 180,000; Full time

Benefits offered by this job

London office with hybrid schedule

Stock options

Pension/NEST

Books, courses, conferences budget

Health insurance

Cycle to work

Volunteer day

Job summary

Motorway, the UK's largest online car-selling platform, is expanding its engineering leadership with a Principal Engineer who will set technical direction across multiple product areas. You will own the AWS relationship, drive architectural decisions, and lead AI initiatives for software engineering, while collaborating with leadership to shape the platform for scale.

The role is based in London with a hybrid work schedule, offering significant scope to influence engineering standards,

Qualifications

• Ten years or more in software engineering, with several in staff or principal level.
• Track record of setting technical direction across teams or product areas.
• Exceptional AWS expertise with production-scale serverless, containers, networking, identity and data services.
• Judgement to evaluate platforms and say no to ones that don’t earn their place.
• Strong API and identity architecture knowledge: OAuth 2.0, OIDC, PKCE, JWT, IAM patterns.
• Experience setting observability and reliability standards and incident practices.
• Ability to read or write code in most languages and trace user requests through to data.

Responsibilities

• Set technical strategy across multiple product areas and justify it with data to leadership.
• Identify cross-cutting architectural risks and resolve them before scaling.
• Set engineering standards, patterns and documentation norms for reliable inputs to engineers and agents.
• Raise reliability, observability, security, and incident practices across engineering.
• Lead AI for Software Engineering initiatives, evaluating models and driving adoption.
• Develop staff engineers and technical leads to multiply leadership capacity.
• Own the AWS relationship on the engineering side, including reviews and cost decisions.
• Represent Motorway publicly at AWS summits, conferences and internal forums.

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 meeting

You could be a great fit if

• You create clarity in situations where no obvious technical path exists

• You challenge the status quo with evidence and worked alternatives, and you have the patience to bring people with you

• You argue for the simplest architecture that meets the requirement, because you've lived with the long-term cost of the alternative

• You carry a pattern library of production failures and over-engineered systems, and you use it to stop others repeating expensive mistakes

• You want the stage rather than tolerate it, and you're as comfortable in a keynote slot as you are in a Monday morning team demo

• You enjoy making the engineers around you better, whether that's mentoring, review, or helping someone prepare their first public talk

• You stay curious about new tools and honest about which ones are worth adopting

We offer a fantastic range of benefits to help you thrive:

• Great work-life balance

• London office location with regular social events, office drinks and free snacks to keep you going

• Hybrid work schedule with 2 days per week in our Central London office

• Stock options so you can share in Motorway's growth and future success

• Pension scheme to plan for your future with our provider NEST

• Strong commitment to your personal development including budget for books, courses, conferences, etc

• Opt-in comprehensive health insurance through BUPA including dental care and fitness discounts

• Cycle to work scheme, save big ££ on a new bike and accessories

• One paid volunteering day a year for you to use as you wish

• Generous parental benefits including 6 months full paid maternity leave, 4 weeks paternity leave and workplace nursery scheme... and much more!