Staff Engineer

Wolt

ABOUT WOLT At Wolt, we create technology that brings joy, simplicity and earnings to the neighborhoods of the world. In 2014 we started with delivery of restaurant food. Now we’re building the delivery of (almost) everything and you’ll find us in over 500 cities in 30 countries around the world. In 2022 we joined forces with DoorDash and together we keep on dreaming big and expanding across the globe. Working at Wolt isn’t always easy, but it’s definitely exciting. Here you’ll learn more, build more, and ship more than in most other companies. You’ll be challenged a lot, but also have a lot of fun on the way. So, if you’re a self-starter with drive and entrepreneurial spirit, this could be the ride of your life. Wolt’s AdTech & Promotions team is building the systems that power how restaurants and brands grow on our platform. From campaign creation to optimization and forecasting, we develop tools that help advertisers make smarter decisions and drive measurable results. As we expand our offering, we are investing in new capabilities that combine real-time data, scalable systems, and intuitive user experiences to unlock the next phase of growth. We’re looking for a Staff Engineer to join the Wolt AdTech & Promotions organization, who can drive technical direction across this space and help us build reliable, scalable systems that directly impact revenue and advertiser success. WHAT YOU’LL BE DOING * Drive the technical vision and architecture for Wolt’s AdTech and Promotions platforms, ensuring they are scalable, reliable, and high-performing. * Provide technical leadership across multiple teams and projects, bringing architectural consistency to complex, large-scale systems. * Work across the end-to-end domain, contributing to backend services, data pipelines, and advertiser-facing tools. * Design and evolve systems that support campaign execution, targeting, ranking, allocation, and reporting in real-time or near real-time environments. * Partner with engineering, product, and data stakeholders to align priorities, improve campaign performance, and manage trade-offs in a revenue-driven environment. * Lead large cross-team projects, guiding them from concept to rollout across multiple regions and time zones. * Ensure strong operational excellence, including observability, reliability, and incident readiness for revenue-critical systems. * Promote best engineering practices, mentor engineers across teams, and support their growth in scalability and system design. * Act as a bridge between technical and non-technical colleagues, ensuring clarity and alignment across functions. * Contribute to the technical roadmaps of AdTech and Promotions platforms by collaborating with other senior engineers. This position is based in London  OUR HUMBLE EXPECTATIONS TECHNICAL EXPERTISE * Proven track record designing and scaling large distributed systems in production environments. * Strong understanding of system architecture, scalability, reliability, and performance optimization. * Experience working with data-intensive and real-time or near real-time systems. * Familiarity with AdTech concepts such as targeting, ranking, attribution, or experimentation is a strong plus. * Ability to adapt quickly to new technologies and languages; while many of our services are written in Kotlin and Go, we are looking for someone language-agnostic. * Ability to dive quickly into new domains and navigate complex system interactions. * Familiarity with modern cloud-native tools and data systems (e.g., Kubernetes, Kafka, MongoDB). COMMUNICATION & INFLUENCE * Strong communicator with the ability to influence, align, and build consensus across diverse teams and stakeholders. * Comfortable working in a global environment across US and international teams. * Skilled at translating complex technical decisions into clear direction for technical and non-technical audiences. * Experience mentoring and coaching engineers, helping raise the technical bar across teams. * Strong sense of ownership combined with a collaborative mindset, able to work effectively across team boundaries to deliver shared outcomes. * Proactive in identifying opportunities and gaps across teams, and driving alignment to solve problems holistically rather than locally. WHAT WE OFFER At Wolt, this role provides a rare opportunity to work on challenging AdTech problems at scale, where technical decisions directly impact revenue and user experience. Our compensation follows a total compensation model, combining a competitive base salary with DoorDash RSUs. You will play a key role in building and evolving the next generation of advertisement tools and platforms, shaping how advertisers create, manage, and optimize campaigns across Wolt. This is not just about maintaining systems, but about defining and scaling new capabilities in a fast-growing domain. As a Staff Engineer, you will have end-to-end ownership and high autonomy, with the ability to influence architecture, product direction, and engineering practices across teams. Your work will have clear, measurable business impact, directly contributing to revenue growth and advertiser success. You’ll be part of a global company operating at scale, collaborating with teams across Europe and the US, and solving problems that span multiple markets, use cases, and customer segments. This role also offers strong opportunities for career growth and scope expansion, whether through deep technical leadership, cross-domain influence, or progression toward more senior individual contributor roles. Alongside the technical challenge, you’ll work with talented engineers and leaders in a diverse and international environment, shaping both our systems and engineering culture while mentoring and learning from others. OUR COMMITMENT TO DIVERSITY AND INCLUSION We’re committed to growing and empowering a more inclusive community within our company, industry, and cities. That’s why we hire and cultivate diverse teams of people from all backgrounds, experiences, and perspectives. We believe that true innovation happens when everyone has room at the table and the tools, resources, and opportunity to excel.

Graphcore

ABOUT THE JOB Validate the ML stack that turns accelerator hardware into trusted AI performance. This role sits where modern ML models meet Graphcore’s software and hardware stack. You will test, benchmark and validate complex systems before they reach customers. Your work will expose regressions, correctness issues and performance limits across frameworks, models and execution environments. You will help teams understand what is working, what is breaking and why. You will run open source models, build automated benchmarking pipelines and create targeted tests for low level ML behaviour. That includes numerical precision, quantisation, attention mechanisms, distributed execution and model subgraphs. This is a role for someone who wants to stay close to how AI systems really work. You will not design new models, but you will make them run reliably on ambitious infrastructure. THE TEAM AND CULTURE The ML QA team is where Graphcore’s ML software stack comes together for validation. Work spans unit tests, full model benchmarks, distributed workloads, simulators, emulators and hardware targets. Engineers are expected to take ownership, question assumptions and improve how testing is done. The team moves quickly, but decisions are grounded in evidence, benchmark data and technical discussion. You will work closely with software, infrastructure and hardware teams. Squads organise around priorities, with space for engineers to shape roadmaps and raise the quality bar. WHAT WE’RE LOOKING FOR · Strong experience in Machine Learning or ML-adjacent software engineering roles. · A solid grasp of neural networks, training, inference, numerical precision and performance trade-offs. · Hands-on experience with PyTorch, TensorFlow, JAX, Triton or similar ML frameworks and tools. · Strong Python skills for automation, experimentation, benchmarking and reporting. · Experience designing, running and analysing ML benchmarks or model experiments. · Confident debugging skills in Linux, with curiosity about model behaviour and system performance. BENEFITS · Unlimited annual leave · Up to 5% matched pension · Phantom equity – share in Graphcore’s success · True flexibility in how and where you work · Office spaces designed for collaboration · Free food and an on-site barista · Health cash plan · Income protection · Life assurance · Along with other benefits you can choose from (private medical insurance, dental plan etc) We welcome people from all backgrounds and experiences and are committed to building an inclusive environment where everyone can do their best work. We’re an equal opportunity employer and recognise that everyone brings different strengths and perspectives. If you need any adjustments during the interview process, just let us know - we’re happy to support you. JOIN THE TEAM AT GRAPHCORE Graphcore is one of the world’s leading innovators in Artificial Intelligence compute. It is developing hardware, software and systems infrastructure that will unlock the next generation of AI breakthroughs and power the widespread adoption of AI solutions across every industry. As part of the SoftBank Group, Graphcore is a member of an elite family of companies responsible for some of the world’s most transformative technologies. Together, they share a bold vision: to enable Artificial Super Intelligence and ensure its benefits are accessible to everyone. Graphcore’s teams are drawn from diverse backgrounds and bring a broad range of skills and perspectives. A melting pot of AI research specialists, silicon designers, software engineers and systems architects, Graphcore brings together deep expertise to solve complex problems and deliver meaningful progress in AI compute. If you want to validate the systems behind next generation AI compute, we’d love to hear from you. Apply now to help build what comes next.

Fonoa

ABOUT ENGINEERING AT FONOA Engineering is central to how we build the business. We focus on solving real customer problems, not just shipping features. We work in small, high-trust teams, with full ownership across the lifecycle, from design to production and beyond. We value: * Ownership – engineers own what they build end-to-end * Simplicity – we break down complex problems into clear solutions * Thinking Big - we innovate with modern technologies (LLMs, AI Agents, etc.) to solve meaningful problems * Quality – scalable, maintainable systems are non-negotiable * Speed & iteration – we ship fast, learn, and improve continuously * Collaboration – we win as a team, not as individuals POSITION OVERVIEW As a Staff Engineer, your role is to improve the system as a whole, both technically and organizationally. You will work on ambiguous, high-impact problems, shape technical direction across teams, and help others build better systems. Your impact comes less from the code you write, and more from how you influence decisions, design, and execution at scale. WHAT YOU WILL DO * Take ownership of complex, cross-team problems that are not clearly defined * Define technical direction and drive system design across domains * Identify and address systemic issues and opportunities early * Simplify complexity through better architecture, patterns, and structure * Improve how teams build by raising standards, tooling, and practices * Mentor engineers and contribute to hiring and team growth * Ensure systems are reliable, scalable, and built for long-term evolution WHAT GOOD LOOKS LIKE * You focus on high-leverage problems and shape how they are approached * You create clarity in ambiguous situations and align teams around it * You improve not just code, but how teams design and build systems * You make others more effective through guidance, feedback, and direction * You operate with long-term thinking, balancing today’s needs with future scale * You adopt emerging AI technologies and create a culture of innovation in your teams At this level, you are expected to “make the whole system, and the people in it, better.” WHAT WE’RE LOOKING FOR * Strong experience designing and operating scalable backend systems * Proven ability to work on ambiguous, high-impact problems * Track record of influencing technical decisions beyond your team * Ability to balance speed, quality, and long-term maintainability * Experience mentoring engineers and improving team practices * Fostering a culture of curiosity and experimentation API DOCUMENTATION For engineers, API design and structure are an important part of evaluating a role. You can explore our API and how we build products here: https://docs.fonoa.com/ TECH STACK We use these technologies today, but we don’t hire for specific tools. We care about engineers who can understand problems, make good technical decisions, and choose the right tools for the job. * Backend: Node.js, Go * Frontend: React, TypeScript * Infrastructure: GCP, k8s, Terraform, Postgres Note: If you don’t think you have the full experience we’re looking for, but you could be a fit and are willing to learn, do apply anyway! We are building a diverse and inclusive team. As part of the recruitment process at Fonoa, we process your personal data in accordance with our Privacy Notice for Job Applicants. This notice explains how and why your data is collected and used, and how you can contact us if you have any concerns.