Senior Software Engineer I - Reliability

About Checkout.com Checkout.com helps businesses succeed in the digital economy. Leading companies such as eBay, ASOS, Klarna, Uber Eats, and Sony rely on our platform to process seamless online payments. Our global network supports billions of transactions each year, focusing on reliability and ease of use. Headquartered in London, Checkout.com operates from 19 offices across six continents. The company values high performance and continuous improvement. Working here means contributing to the future of fintech alongside teams striving for excellence. Role Overview: Staff Software Engineer - Streaming The Data and AI Platform Team is looking for a Staff Software Engineer to help build a scalable platform for AI-driven streaming and batch data applications. This platform will improve how data is shared and used across Checkout.com, supporting business growth and performance. The team’s mission is to make it easier for internal teams to collect, store, process, and use data for impactful AI projects and data products. The focus is on reducing technical overhead so engineers can spend more time solving business challenges, not managing infrastructure or deployments. Current work lays the foundation for systems that will scale to support hundreds of teams and handle petabytes of data. Main Responsibilities Design and develop a highly available event streaming platform using technologies like Kafka and Flink. Offer technical leadership and mentorship, providing strategic direction and building strong relationships with engineers and managers across the organization. Work with cross-functional teams to deliver data solutions that support business goals. Location This role is based in London.

C/C++ Software Engineer (Video)Location: LondonAbout UsAt New Route Recruitment Limited, we are proud to present our state-of-the-art video platform designed for live, social, and mobile environments. Our cloud-based technology alleviates the conventional challenges associated with professional video production and distribution.We collaborate with some of the world's leading broadcasters and rights holders, including renowned names like Sky Sports, BT Sport, Eurosport, ITV, Turner, The Premier League, LaLiga, The FA, Buzzfeed, AELTC Wimbledon, and GOAL.com. Our platform seamlessly integrates with major social media channels such as Facebook, Instagram, Periscope, Twitter, and YouTube, and we are a recognized global partner for Facebook Live.Leveraging Amazon Web Services as our primary hosting provider, our platform is designed for scalability and high availability to serve a global clientele. This cloud-based infrastructure empowers our engineers with agility, enabling them to explore innovative solutions while ensuring reliability and rapid development cycles.We believe in the potential of nurturing bright graduates and junior engineers, which we view as vital to our growth. From day one, you will be paired with a mentor who will assist you with technical inquiries and guide your career path by helping you identify your focus area within our platform (video, data, front-end, architecture, streaming, etc.) while providing regular performance evaluations.Your well-being and commitment to our team are paramount. We encourage pushing the boundaries with cutting-edge technologies and provide you with significant responsibilities from day one—overseeing the entire product lifecycle: from design and architecture to deployment, support, and monitoring in production. This approach ensures that you feel engaged, challenged, and impactful in your role.Our commitment to creating a supportive environment has contributed to the long-term retention of our talent. Many of our current senior engineers, including our Product Owner and Lead Software Architect, started as graduate engineers and have evolved into key leadership roles within the organization.We value social interactions and fun, offering various activities to foster team spirit.If you are driven by technology and eager to make a difference, we want you on our team!As a C/C++ Software Engineer, you will play a crucial role in designing, building, and supporting the platform’s Media Engine, which facilitates live and on-demand encoding, including applying exciting video effects.

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 our innovative team at Kaluza as a Senior Software Engineer I, where you will play a crucial role in shaping the future of energy technology. You will collaborate with talented engineers to design and implement software solutions that enhance our platform's scalability and performance.

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.

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.

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.

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

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 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.

Role overview Wise seeks a Senior Software Engineer I to join the Enterprise division, concentrating on banking solutions. This London-based position involves building and refining software that powers financial transactions for enterprise clients. What you will do Collaborate with a cross-functional team to design, develop, and implement software tailored for banks and enterprise partners. Apply technical expertise to strengthen the Wise platform, supporting enterprise-scale financial transactions. Contribute to delivering dependable, high-quality services for clients in the banking sector. Location This role is located in London.

Join our dynamic Product R&D team at On Running, where we are experiencing robust growth and innovation. We are seeking a dedicated Staff Software Engineer with a strong emphasis on event-driven architectures to elevate our business to new heights.As a pivotal member of our engineering team, you will lead the charge in developing data streaming solutions for product data across its entire lifecycle. Your role will not only involve hands-on coding but also mentoring fellow team members, sharing your expertise, and shaping the technical trajectory of our organization.You will be based in London (or within a commutable distance) and will collaborate in the office two days a week. Your work will involve close collaboration with teams in Zurich, Berlin, Ho Chi Minh, and London, engaging with both Technology and Product Development departments across On's global offices.

Why Join Nebius?Nebius is at the forefront of a transformative wave in cloud computing, dedicated to empowering the global AI economy. We develop innovative tools and resources that enable our clients to tackle real-world challenges while minimizing infrastructure costs and the necessity for extensive AI/ML teams. Our employees are positioned at the leading edge of AI cloud infrastructure, collaborating with some of the most experienced and visionary leaders and engineers in the industry.Our Work EnvironmentWith our headquarters in Amsterdam and a presence listed on Nasdaq, Nebius operates on a global scale, featuring R&D centers across Europe, North America, and Israel. Our diverse team of over 1400 employees includes more than 400 highly skilled engineers with profound expertise in both hardware and software engineering, complemented by a dedicated AI R&D team. The ProductIn an ever-changing landscape, the reliability of AI systems hinges on AI agents utilizing up-to-date, verified real-world data. Our search function is the cornerstone that enables this capability.We are developing a state-of-the-art agent-native search platform tailored specifically for AI systems instead of human users. Our solution offers programmatic, low-latency, and observable search APIs that AI agents leverage to retrieve, filter, and reason over real-world data at scale.The RoleWe are on the lookout for a Senior Software Engineer to contribute to the indexing and data processing layer of our innovative search engine designed for agentic AI consumption. In this role, you will be tasked with developing systems that ingest, process, and organize vast amounts of data into efficient, queryable formats. Your primary focus will be on offline and nearline pipelines, ensuring data freshness, completeness, and accessibility for downstream retrieval systems. You will thrive in an environment where throughput, scalability, and data accuracy are paramount, designing systems capable of managing tens of gigabytes per second across dynamically evolving datasets.

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.

Join our innovative team at getscope as a Senior Software Engineer. In this pivotal role, you will design, develop, and implement cutting-edge software solutions that will drive our projects forward. Collaborate with cross-functional teams to translate business needs into technical requirements while ensuring high quality and performance of applications.

Join Runna as a Senior Software Engineer II, where you'll play a pivotal role in enhancing our software solutions. You will collaborate with cross-functional teams to design, develop, and implement robust applications that meet our customers' needs. Your expertise will help us push the boundaries of technology, ensuring our products remain at the forefront of the industry.

About the PositionWe are seeking a highly skilled and motivated Senior Software Engineer - Generalist to join our innovative team at Anza. This role is pivotal in enhancing our Agave client and the overarching Solana network, focusing on performance, reliability, and security.About UsAnza is a cutting-edge R&D lab focused on the Solana blockchain, dedicated to revolutionizing blockchain performance and scalability. With a team of seasoned executives and core engineers, we tackle the most pressing challenges in the Web3 space. We believe in the power of collaboration and transparency, building robust protocols that can support the crypto ecosystem's growth and security.Your ResponsibilitiesDevelop and optimize our technical infrastructure, particularly the Agave client within the Solana ecosystem.Design and implement testing frameworks to simulate adversarial attacks and proactively identify vulnerabilities.Analyze performance metrics to pinpoint and resolve bottlenecks.Collaborate with subject matter experts to understand and define performance requirements for code components.Benchmark new solutions to enhance system reliability and performance.Work alongside cross-functional teams to architect solutions focused on scalability, security, and optimal performance.Contribute to all stages of the software development lifecycle, ensuring seamless transitions through development, staging, and production.Document architecture and processes to promote standardization and knowledge sharing across teams.