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Senior Software Engineer I United Kingdom Jobs (On-site work)

15 Job Offers

Senior Software Engineer
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Senior Software Engineer sought by a London health-tech scale-up to scale a platform used by 100k+ customers. You’ll own problems end-to-end, working across Python backend, React/TypeScript frontend, and AWS infrastructure. Ideal candidates have 5+ years experience, actively use AI in their workf...
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United Kingdom , London
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100000.00 GBP / Year
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Orbis Consultants
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Senior Software Engineer
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Join a greenfield AI startup in London redefining innovation discovery and protection. As a Senior Software Engineer, you’ll build production systems from scratch using Java, TypeScript, or Python, integrate with LLMs, and collaborate directly with founders. No legacy code or bureaucracy—just fas...
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United Kingdom , London
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120000.00 - 150000.00 GBP / Year
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Linux Recruit
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Senior Embedded Software Engineer
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Senior Embedded Software Engineer sought to architect next-gen motion control systems for robotics and industrial automation. This role demands strong C/C++, ARM, and RTOS/bare metal expertise to optimize real-time algorithms. Based in Gloucestershire, you'll join a global R&D team solving comple...
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United Kingdom , Gloucestershire
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Not provided
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T2M Resourcing
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Senior Software Engineer
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Senior Software Engineer sought in Belfast to build high-quality, scalable applications impacting global users. You will drive technical decisions, mentor junior developers, and apply best practices in security and performance. Ideal for experienced engineers proficient in full-stack development,...
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United Kingdom , Belfast
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Not provided
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Kainos
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Senior Software Engineer
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Shape the future of technology as a Senior Software Engineer in Central London. You will explore emerging tech, lead rapid prototyping, and develop secure, cloud-native solutions for unique engineering challenges. This role requires DV security clearance and offers a strong pension, dedicated dev...
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United Kingdom , Central London
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79969.00 GBP / Year
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Social Value Portal Ltd
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Senior Full-Stack Software Engineer, (Forward Deployed), GPS
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Join Scale's Global Public Sector team in London as a Senior Full-Stack Engineer. Build impactful AI applications using React, TypeScript, Python, and cloud platforms. Partner directly with clients to deploy and architect scalable, production-grade solutions.
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United Kingdom , London
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Not provided
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Scale
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Senior Backend Software Engineer
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Join a leading crypto company in London as a Senior Backend Engineer. Design and scale high-performance, event-driven systems for real-time blockchain transactions. Leverage your expertise in distributed systems and Python/C++/Java, with a move to Rust. Build impactful infrastructure in a fast-pa...
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United Kingdom , London
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150000.00 GBP / Year
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Oho Group Ltd
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Senior Software Engineer
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Join our London team as a Senior Software Engineer. Design and scale a high-performance, event-driven backend platform using modern technologies. Leverage your expertise in distributed systems and Python/C++/Java, with an opportunity to transition to Rust. Enjoy a strong engineering culture, lead...
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United Kingdom , London
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150000.00 GBP / Year
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Oho Group Ltd
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Senior Software Engineer
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United Kingdom , London
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150000.00 GBP / Year
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Orbis Consultants
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Senior Full-Stack Software Engineer
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Join our London team as a Senior Full-Stack Engineer. Drive innovation using Go, Python, and React within a product-focused, agile environment. Enjoy a hybrid model, 27 days leave, bonus, and comprehensive benefits while revolutionizing controls management.
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United Kingdom , London
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Not provided
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Citi
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Senior Software Engineer
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Join Equinox in London as a Senior Software Engineer. Lead complex projects, design system architectures, and mentor junior developers using Java and Kafka. Enjoy a hybrid model, bonus, private healthcare, and 27 days leave.
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United Kingdom , London
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Not provided
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Citi
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Senior Software Engineer
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Join Perk as a Senior Software Engineer in Edinburgh. Develop our next-gen travel & spend platform using Python/Django and/or React. We seek an expert full-stack developer with a product mindset, passion for quality, and Agile experience. Enjoy competitive pay, equity, private healthcare, and amp...
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United Kingdom , Edinburgh
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Not provided
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Yokoy
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Senior Automation Software Engineer
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Lead complex automation solutions for naval combat systems as a Senior Engineer in New Malden. Utilize your C#/PowerShell and VMware expertise to design and maintain critical deployment frameworks. This role offers technical leadership, mentorship, and the chance to shape automation strategy with...
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United Kingdom , New Malden
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37.25 GBP / Hour
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Outsource UK
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Senior Software Engineer
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Join a world-class cybersecurity startup in London as a Senior Software Engineer. Shape architecture and drive technical decisions for a critical, high-impact product. Requires 5+ years' experience with Python, Java, C#, Rust, or Go, and a passion for building secure, scalable systems. Enjoy comp...
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United Kingdom , London
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60000.00 - 120000.00 GBP / Year
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Oho Group Ltd
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Senior Software Engineer
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Join a world-class cybersecurity startup in London as a Senior Software Engineer. Shape architecture and drive technical decisions for a critical, high-impact product. Requires 5+ years' experience with Python, Java, C#, Rust, or Go, building scalable systems. Enjoy real ownership, competitive pa...
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United Kingdom , London
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Salary
60000.00 - 120000.00 GBP / Year
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Oho Group Ltd
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Until further notice

About the Senior Software Engineer I role

A Senior Software Engineer I is a pivotal and experienced role within the technology industry, representing a professional who has mastered the fundamentals of software development and is now operating at a high level of technical proficiency and ownership. This position is a crucial step on the engineering career ladder, often sitting between a mid-level engineer and a staff or principal engineer. Professionals searching for Senior Software Engineer I jobs are typically seeking roles where they can architect complex systems, mentor others, and drive significant technical projects to completion with substantial autonomy.

In this role, individuals are generally responsible for the end-to-end delivery of software features and systems. This involves translating high-level business requirements into robust technical designs, writing clean, efficient, and maintainable code, and conducting thorough code reviews to uphold team standards. A Senior Software Engineer I is expected to own substantial components of a codebase, taking responsibility not just for implementation but also for the long-term health, performance, and scalability of their work. They proactively identify technical debt and performance bottlenecks, advocating for and implementing improvements. Collaboration is key; they work closely with product managers, designers, and other engineers to refine requirements and ensure the final product aligns with both user needs and technical best practices.

Common responsibilities for these professionals include designing system architecture, making critical decisions on technology selection, and establishing patterns and practices for their team. They are often the go-to person for solving the most challenging technical problems. Leadership is a subtle but important aspect, demonstrated through mentoring junior engineers, sharing knowledge, and sometimes leading small project teams. They ensure quality by championing testing strategies, including unit, integration, and end-to-end tests, and by integrating monitoring and observability into their systems.

Typical skills and requirements for Senior Software Engineer I jobs include 5+ years of professional software development experience, with deep expertise in one or more modern programming languages (such as Java, Python, C++, JavaScript/TypeScript, or Go) and their ecosystems. A strong grasp of software design principles, data structures, algorithms, and system design is essential. Experience with cloud platforms (AWS, Azure, GCP), containerization (Docker, Kubernetes), and CI/CD pipelines is highly common. Beyond technical prowess, successful candidates demonstrate excellent problem-solving abilities, effective communication skills for discussing technical concepts with both technical and non-technical stakeholders, and a proactive, ownership-driven mindset. They are expected to navigate ambiguity, make well-reasoned trade-offs, and continuously learn and adapt to new technologies. For those seeking impactful roles where they can shape technology and guide teams, Senior Software Engineer I jobs offer a challenging and rewarding career path at the heart of innovation.