Senior EC&I Engineer

Join Assystem as a Senior EC&I Engineer, where you will play a critical role in delivering innovative engineering solutions within the energy sector. You will be responsible for designing, implementing, and managing electrical, control, and instrumentation systems that contribute to the efficiency and safety of power generation projects.Your expertise will facilitate the integration of cutting-edge technology, ensuring compliance with industry standards while fostering a collaborative environment. This is an excellent opportunity for professionals looking to advance their careers in a dynamic and supportive workplace.

Role overview The Senior Software Engineer I at Runna will play a key part in shaping how users interact with the company’s products. The work centers on designing, developing, and maintaining applications that support a strong user experience. Expect to take a hands-on approach, working closely with colleagues from different teams to deliver solutions that scale and perform reliably. Location This role is based at the Runna office in London.

Join Axon and become a Force for Good.At Axon, we are dedicated to Protecting Life. Our mission drives us to tackle society's most pressing safety and justice challenges through our innovative ecosystem of devices and cloud-based software. We believe in collaboration, openness, and the value of diverse perspectives from our customers, communities, and each other.Life at Axon is dynamic, demanding, and impactful. Here, you will take ownership of your work and instigate tangible change. Experience continuous growth while contributing to a mission that truly matters, at a company that values your contributions.Your ImpactThis position is ideal for innovators who thrive in a startup-like environment. In Axon's Global Artificial Intelligence division, you will develop a groundbreaking product with a small, dedicated team, aiming to deliver something unprecedented to the market swiftly.As a Senior Software Engineer I, you will spearhead critical aspects of the product from conception to launch. You will make informed architectural decisions, maintain high quality while accelerating development, and assist the team in transforming prototypes into a scalable solution.This role is fundamentally AI-driven: AI will be integral to your delivery approach, not merely an addition.What You’ll DoOversee the development of significant product features and services; manage end-to-end ownership from design through to operations.Clarify product direction amidst uncertainty: articulate the problem, define MVP scope, establish success metrics, and ensure stakeholder alignment on project completion criteria.Create and deploy software using AI methodologies across the Software Development Life Cycle (SDLC), with thorough validation practices to ensure accuracy and quality.Utilize engineering metrics (lead time, PR throughput, defect rates, test coverage, incident load) to assess and enhance delivery outcomes, refining team shipping processes.Make architectural choices that effectively balance speed and scalability, recognizing when temporary solutions become permanent.Implement and uphold engineering best practices that enhance productivity (testing strategies, CI/CD, observability, and sensible release methodologies).Collaborate closely with Product and Design teams (and function effectively in their absence) to prioritize, sequence, and deliver the highest-value increments.Mentor fellow engineers while fostering a culture of trust and ownership.

Join Axon as a Senior Software Engineer I and be at the forefront of developing innovative software solutions that enhance public safety. You will leverage your expertise to design, build, and maintain software systems that have a meaningful impact.

Role overview Wise is looking for a Senior Software Engineer I focused on reliability to help strengthen the stability and performance of our platforms. This role centers on building and maintaining scalable systems that support our global customer base. What you will do Work closely with engineers and other team members to design solutions that improve service reliability. Develop and maintain systems that handle growth and changing demands. Contribute to ongoing efforts to monitor, optimize, and ensure the performance of our services. Location This position is based in London.

Join Our Visionary Team at Runna!At Runna, we are on a mission to create the premier training platform for runners. Our innovative app empowers everyday athletes to excel, providing access to top-notch training, expert coaching, and a supportive community whether you're aiming to improve your 5k or preparing for your first marathon.Our rapid growth is fueled by a strong vision, backed by a recent $6.5M funding round led by JamJar and supported by Eka Ventures, Venrex, and Creator Ventures. In 2024, we had the honor of being named one of Apple’s three global finalists for the iPhone app of the year, and in 2025, we proudly became a part of Strava!We aspire to be the leading global training platform for millions of runners. With our recent acquisition by Strava accelerating our growth, this is an exciting time to join us. As part of our dynamic Train Team, which includes over 35 professionals from engineering, product, design, and coaching, you will play a crucial role in delivering exceptional training experiences to hundreds of thousands of runners worldwide. You will engage in developing personalized training plans at scale, analyzing performance data, and providing insights to our users based on their training and environmental conditions.We embrace a flexible hybrid working model, requiring you to be on-site three days a week at our London office.

Role Overview Checkout.com is hiring a Senior Engineer I for the Workplace Technology team in London. This role focuses on strengthening the company’s internal tech infrastructure and supporting projects that make daily work smoother for employees. What You Will Do Contribute to projects that improve and streamline workplace technology systems. Work closely with colleagues to identify and solve technical challenges in the office environment. Help shape solutions that enhance the employee experience across the company. What We’re Looking For Strong attention to detail and a drive for practical, effective solutions. Comfort working in a collaborative team setting. Interest in developing and optimizing technology that supports workplace productivity.

Senior Software Engineer I at Checkout.com, London About Checkout.com Checkout.com supports digital payments for companies like eBay, ASOS, Klarna, Uber Eats, and Sony. Headquartered in London, the company operates across six continents and focuses on simplifying online transactions for businesses worldwide. What You’ll Do Senior Software Engineers at Checkout.com help design and build advanced payment technologies. This work directly improves merchant capabilities and supports the company's global mission. The role involves: Leading projects that align with strategic goals Collaborating with teams that prioritize customer needs Bringing technical insight and creativity to solve new challenges Influencing engineering priorities and direction What Sets This Team Apart Innovation and performance drive the culture at Checkout.com. Every team member plays a part in shaping the future of fintech. Senior engineers are trusted with real responsibility and the chance to make a visible impact. Location This position is based in London. Learn more about the company at Checkout.com.

Job Title: Senior Software Engineer I Location: London - Hybrid Salary: £60,000 - £80,000 Team: Flex Reporting to: Software Engineering Manager Note: Currently, we are unable to provide visa sponsorship for this position. We are dedicated to fostering a diverse, global team and evaluate our sponsorship policy on a role-by-role basis. Please monitor our careers site for future opportunities that may offer visa sponsorship. Kaluza is at the forefront of transforming energy complexities into seamless solutions through our Energy Intelligence Platform. We empower energy companies to navigate modern challenges while expediting the transition to a clean, electrified future. Utilizing cutting-edge Data, AI, and real-time decision-making, we convert energy intricacies into growth opportunities for our partners. By merging predictive algorithms with human-centered design, Kaluza ensures that clean energy is both reliable and affordable. Our teams span across Europe, North America, Asia, and Australia, and we maintain a joint venture with Mitsubishi Corporation in Japan. We collaborate with industry leaders such as OVO, AGL, and ENGIE, alongside innovators like Volvo and Volkswagen. Key Responsibilities: As a member of the Flex platform team, you will play a critical role in developing systems that connect energy retailers, grid operators, and consumers, fostering a more adaptable and dynamic energy infrastructure. Your daily tasks will involve designing and implementing scalable features, including integrating technologies like electric vehicles and facilitating customer offerings such as “Charge Anytime.” You will collaborate closely with data scientists and backend engineers on fundamental optimization challenges, taking ownership of features from conception through continuous enhancement. Throughout this process, you will produce high-quality, well-tested code and contribute to a robust engineering culture, developing software that significantly contributes to decarbonizing transport and home energy usage at scale. Qualifications: Proficiency in at least one programming language and experience contributing to diverse, complex systems. Strong understanding of contemporary engineering practices, encompassing continuous delivery, test automation, and agile methodologies. A fervor for collaborating within cross-functional teams to tackle challenging problems and build innovative features.

Join Our Visionary Team to Create the Premier Training Platform for RunnersAt Runna, we empower everyday runners to achieve their best by developing an exceptional app that offers top-tier training, coaching, and community support. Whether you're aiming to enhance your 5k performance or prepare for your inaugural marathon, we're here to guide you every step of the way.Our growth trajectory is remarkable! In November 2023, we successfully secured a $6.5M funding round led by JamJar, with contributions from Eka Ventures, Venrex, and Creator Ventures. In 2024, we were honored to be recognized by Apple as one of three global finalists for the iPhone App of the Year, showcasing the innovation and impact of our platform. The journey continued with our acquisition by Strava in 2025!Our aspirations are ambitious: we aim to be the leading global training platform for millions of runners worldwide. As we evolve with purpose, we seek passionate individuals who want to contribute to something meaningful and impactful. With Strava's recent acquisition propelling our mission forward, this is an extraordinary time to become a part of our journey. The Growth Team You’ll Be JoiningWe are on the lookout for a skilled, inquisitive, and experimentation-driven Senior Full Stack Engineer to join our Growth Engineering team. This team is responsible for critical aspects of the user journey at Runna, focusing on both web and app platforms to craft high-quality experiences that convert first-time visitors into dedicated subscribers. You will collaborate closely with product, design, and data teams, as well as our founders and CTO, to enhance how new users discover and engage with Runna.Your ResponsibilitiesDesign, develop, test, and deploy high-impact user journeys and subscription funnels aimed at transforming curious visitors into active, engaged subscribers.Create and execute experiments across both web and app (including onboarding processes, paywalls, and plan discovery experiences) to optimize conversion at every stage of the user journey.Work collaboratively with Product, Design, and Data teams to identify opportunities, establish clear success metrics, and make informed decisions based on experimental outcomes.Partner with other teams to ensure users enjoy a seamless and consistent experience as they navigate through various products and platforms.Implement and sustain the instrumentation, tracking, and tools necessary for understanding user behavior, quickly identifying issues, and accurately measuring impact.Take ownership of features and initiatives that drive user engagement and retention.

About Axon Axon’s mission is to safeguard life. The company develops devices and cloud-based software focused on public safety and justice. Teams at Axon work together to address complex challenges, valuing transparency, empathy, and a range of perspectives from users, communities, and colleagues. Role Overview: Senior Site Reliability Engineer I This position sits within the Site Reliability Engineering (SRE) team. The main focus: tackle real-time challenges across Axon’s mission-critical, cloud-native services. The work centers on maintaining the reliability and quality customers expect. Collaboration is key, both within the SRE group and across the wider engineering organization, to help product teams deliver new features consistently. Work Location and Flexibility This role is based in London, England, United Kingdom. Axon uses a hybrid working model. Team members are expected onsite from Tuesday to Friday, with remote work on Mondays (unless a workplace accommodation is granted). The company emphasizes in-person collaboration to support teamwork, mentorship, and shared success.

Join our dynamic team at Wise as a Senior Software Engineer I focused on Investments, where you will leverage your expertise in Java to drive innovative solutions. You will collaborate with cross-functional teams to enhance our investment platform, ensuring scalability, performance, and security. Your contributions will directly impact our mission to make money transfers and investments seamless and accessible for everyone.

Job Title: Senior Engineer I Location: London, Bristol, or Edinburgh (Including Hybrid) Salary: £60,000 - £82,500 Team: Developer Experience Reporting To: Head of Engineering Closing date: Friday 30th March 2026 This role is based in the UK and requires an existing right to work in the UK. At this time, we are unable to offer visa sponsorship for this role. We are committed to cultivating a diverse, global team and our sponsorship policy is assessed on a role-by-role basis. We encourage you to regularly visit our careers site for updates on future opportunities where we may offer visa sponsorship. Kaluza is at the forefront of the energy revolution, transforming complex energy challenges into streamlined solutions. We empower energy companies to navigate contemporary challenges while driving the transition to a sustainable, electrified future. Our platform orchestrates millions of real-time decisions across homes, devices, markets, and grids. By merging predictive algorithms with user-centric design, Kaluza ensures clean energy is reliable, affordable, and seamlessly integrated into daily life. With teams across Europe, North America, Asia, and Australia, alongside a joint venture with Mitsubishi Corporation in Japan, we support industry leaders such as OVO, AGL, and ENGIE, as well as innovators like Volvo and Volkswagen. What will I be doing? In this impactful role, you will be instrumental in architecting and enhancing our Internal AI Engineering Platform. You will construct the infrastructure, from Model Context Protocol (MCP) servers to shared workflows, enabling our software teams to accelerate their development while ensuring system reliability and security. Your contributions will significantly influence Kaluza’s efforts to minimize defects, enhance productivity, and establish a benchmark for AI-driven development. AI Tooling Orchestration: Spearhead the trials and implementation of advanced engineering tools, including Claude Code, Kiro, and Opencode, ensuring their seamless integration into the developer workflow. Infrastructure & Connectivity: Design and maintain our MCP (Model Context Protocol) registry, creating a secure and scalable process for approving and deploying new servers and tools. Shared Workflows: Develop and uphold shared services and standards that standardize coding practices and automate repetitive architectural tasks across teams to facilitate AI workflows. Spec-Driven Development: (additional responsibilities to be defined).

Menlo Security helps organizations around the world connect, communicate, and collaborate securely. The company supports a wide range of clients, including Fortune 500 firms, nine of the ten largest global banks, and the Department of Defense. The shift in work patterns since COVID-19 has only increased the importance of Menlo’s mission. Menlo Security is entering a new phase of growth, expanding beyond its current team of 400. The company values empathy, adaptability, and a commitment to results. Team members are expected to work ethically, stay organized, focus on service, and contribute to a culture that values both giving and receiving feedback. Menlo is backed by investors such as Vista Equity Partners, General Catalyst, JPMC, American Express, HSBC, and Ericsson Ventures. Role Overview The Senior Engineer I - Web Isolation (UK Region) will join the UK-based Web Isolation team. This group builds and maintains Menlo’s remote browser technology, which protects millions of users worldwide through the company’s cloud platform. The work spans desktop and mobile, with a focus on security at every layer. Key technical areas include: Chromium internals Networking Video and audio integration Advanced HTML5 (such as WebGL and WebRTC) Containerization Load balancing and scalability The team values strong design, thorough code reviews, and a collaborative approach. Engineers with deep systems-level experience outside of browsers are encouraged to apply if they are ready for new technical challenges. For more about the kind of work involved, see the Menlo blog: Mobile Isolation Era Begins. What You Bring Extensive understanding of browser technology Hands-on experience with Chromium internals Background in networking, video, and audio technologies Familiarity with advanced HTML5 features (WebGL, WebRTC) Proficient C++ programming skills Ability to use modern AI tools in development workflows Knowledge of Python, Rust, and JavaScript is a strong plus Location Role based in the UK region (EMEA).

Wise is looking for a Senior Software Engineer I to join the Account Communications team in London. This position focuses on refining the company’s communication platforms and shaping the ways customers connect with Wise. Key responsibilities Build and improve systems that handle customer communications Contribute to projects that have a direct impact on the customer experience Work closely with engineers and cross-functional teams to deliver dependable solutions Location This role is based in London.

Role overview Wise is looking for a Senior Software Engineer I to join the Account Management team in London. This group develops and maintains the core software that lets users manage their accounts with ease. The team’s work plays a key part in Wise’s mission to make money transfers fair and accessible for everyone. What you will do Design, build, and maintain applications that power account management features Collaborate with engineers, product managers, and other teams to deliver reliable products Focus on the quality and usability of account management tools for Wise customers Requirements Strong technical background and experience developing software at scale Ability to work well with cross-functional teams Motivated to build products that enhance the user experience

Wise is looking for a Senior Software Engineer I focused on stream processing to help improve international money transfers. This position is based in London and centers on building systems that keep payments fast and affordable. Role overview This role involves working closely with teams across the company to design, build, and maintain scalable streaming data architectures. The systems developed here support Wise’s core financial services, handling large volumes of real-time data. What you will do Collaborate with cross-functional teams to deliver reliable streaming data solutions Design and implement scalable architectures for processing financial transactions Maintain and improve existing stream processing systems Location This position is located in London.

At Menlo Security, we are dedicated to empowering secure connections, communication, and collaboration across the globe. Our mission has become increasingly vital in the wake of COVID-19, as we serve a diverse clientele that includes Fortune 500 companies, 9 out of the 10 largest global banks, and the Department of Defense.As we evolve from 400 employees, we seek passionate and agile individuals who resonate with our mission. The ideal candidate is ethical, exceptionally organized, dedicated to completion, service-oriented, and open to feedback while confidently providing guidance to others.With robust financial backing from top-tier investors including Vista Equity Partners, General Catalyst, JPMC, American Express, HSBC, and Ericsson Ventures, Menlo Security is poised for significant growth.Role OverviewWe invite skilled engineers to join our Web Isolation team, focusing on our cutting-edge remote browser technology utilized on desktop and mobile platforms, catering to millions globally via Menlo's cloud services. Your work will encompass areas such as Chromium internals, networking, video/audio, advanced HTML5 features, containerization, load balancing, scaling, and cost-efficiency, all while maintaining a strong emphasis on security. Our team fosters a collegial environment with a robust culture of design and code review. We welcome applicants possessing deep systems-level expertise from non-browser domains to tackle innovative challenges. For a glimpse into our challenges, visit our blog: here.Candidate ProfileThe ideal candidate will possess a profound understanding of browsers and relevant technologies. You should have experience (or be willing to gain experience) in areas such as Chromium internals, networking, video/audio processing, and advanced HTML5 features including WebGL and WebRTC.

Become a Force for Good with Axon.At Axon, we are committed to the mission of Protecting Life. We tackle society's most urgent safety and justice challenges through our innovative devices and cloud-based software. Our collaborative spirit drives our success as we engage with diverse perspectives from our customers, communities, and each other.Working at Axon is fast-paced, fulfilling, and engaging. You will have the opportunity to take ownership and enact real change while growing in a mission-driven environment where your contributions are valued.Your ImpactAs a Senior Software Engineer within the Infrastructure Services team at Dedrone, you will be tasked with designing, building, and enhancing the core systems that support our developer platform and critical backend services. Your robust software engineering skills coupled with extensive infrastructure knowledge will ensure our platform remains scalable, reliable, and secure. This role transcends traditional infrastructure operations; you will create production-ready backend services, design cloud-native systems, and manage the CI/CD and runtime environments that underpin our product ecosystem. Your influence will shape engineering standards, enhance developer experiences, and steer architectural decisions across Dedrone’s product teams.What You’ll DoWork Location: This position is situated in our London office following a hybrid work model. We emphasize in-person collaboration, requiring team members to be on-site from Tuesday to Friday, with the flexibility for remote work on Mondays, unless a workplace accommodation is in place. We believe that connection drives innovation, and our in-office culture is crafted to promote meaningful teamwork, mentorship, and collective success.Reports to: Engineering Manager, Infrastructure ServicesBackend & Platform Service EngineeringDesign, construct, and sustain production-grade backend services (primarily using Java, Go, or Python) that facilitate deployment orchestration, internal APIs, and developer platform functionalities.Contribute to architectural decisions encompassing service boundaries, API design, persistence layers, scalability strategies, and fault tolerance.Enhance performance, reliability, and maintainability of platform services through rigorous testing practices and meticulous system design.Manage and evolve shared services governed by the Infrastructure Services team.CI/CD & Developer PlatformOwn, design, and refine CI/CD systems that support Dedrone’s distributed product ecosystem.

Role overview Ramboll Group is hiring a Director of Highways Market for the Transport UK&I division, based in London. This senior leader shapes growth and sales strategy across the highways sector, with a focus on strengthening market presence and supporting sustainable development goals. What you will do Develop and implement strategies to expand Ramboll’s position in the highways market Lead sales efforts and identify new business opportunities within the sector Guide and motivate a team focused on delivering high-quality, innovative projects Ensure client needs are met while maintaining the company’s standards for integrity and quality Champion initiatives that support Ramboll’s commitment to sustainability About the team Work with a group dedicated to advancing project delivery and fostering innovation in the UK and Ireland’s transport infrastructure. Collaboration and a shared commitment to excellence are at the heart of this team’s approach.