Senior Backend Software Engineer (UK)

Join Our Innovative Team at DexAt Dex, we harness the power of AI to revolutionize recruitment by connecting outstanding software engineers with leading tech companies. As one of the fastest-growing startups in the UK, we have secured $3.1 million in funding from prestigious investors such as a16z and Concept Ventures. Our mission is to develop a cutting-edge voice agent, advanced matching engine, and a seamless web application experience that transforms the landscape of talent acquisition.We are looking for a passionate Backend Software Engineer to join our dynamic team. In this role, you will contribute to building our innovative products and AI-driven agent systems, enabling a deeper understanding of our users and their unique opportunities.Your Role and ResponsibilitiesAs a Backend Software Engineer at Dex, you will take ownership of the backend infrastructure that powers our voice agent and other applications. You will be working with a modern tech stack that includes Python, FastAPI, Postgres, Redis, Docker, and Pydantic AI, all hosted on Google Cloud Platform (GCP). Your responsibilities will encompass:Product Backend: Manage critical components of our backend architecture, ensuring new features are implemented securely and are scalable from inception.Agent Backend: Enhance the infrastructure supporting our voice agent, which includes conducting evaluations, improving information extraction methods, and guaranteeing reliable performance at scale.Observability: Implement monitoring, logging, and performance metrics to maintain visibility into our production systems.Matchmaking: Design and optimize the systems that drive our AI-powered talent matching engine.What You Will AchieveArchitect and develop scalable backend systems for AI workflows and product infrastructure.Ensure reliability and performance of the systems supporting our voice agent and web application.Collaborate with team members to set technical direction, architecture, and long-term objectives.Create and maintain robust APIs, authentication frameworks, and database designs.Work closely with product managers, designers, and engineers to build infrastructure that adapts to changing requirements.Contribute to establishing best practices for system reliability, performance, and deployment speed.

Join Our Innovative Team as a Senior AI Engineer (Agentic Systems)At StarCompliance, we are at the forefront of creating software solutions that address critical compliance needs for our global clientele. As we integrate AI as a fundamental capability throughout our software development lifecycle, we invite you to be part of this transformative journey.We are looking for a Senior AI Engineer to spearhead the practical implementation and expansion of AI-assisted and agentic engineering within our teams. This is a hands-on role where you will engage directly with real codebases, leveraging cutting-edge AI-native development environments (Cursor preferred) to revolutionize the software development process.Your mission will be to evolve AI from a mere tool into a fully embedded system that is repeatable and scalable. You will craft and execute playbooks, establish workflows, and define patterns that allow our teams to harness the power of parallel AI agents, facilitate autonomous code reviews, and create AI-driven delivery pipelines. Additionally, you will play a pivotal role in launching new initiatives, ensuring they are built on the right architecture and AI-enabled engineering practices from the outset.This position is part of our R&D Engineering team and collaborates closely with Platform, QA, and Product Engineering. Here, influence is gained through tangible delivery rather than hierarchy.Our Vision of AIWe view AI not just as an assistant, but as an integral component of our engineering ecosystem. We expect engineers in this role to embrace this perspective and drive our AI initiatives forward.

At Elliptic, we are pioneering the development of AI-driven tools that empower compliance teams to swiftly and confidently investigate cryptocurrency transactions. Our Automation Forge team is at the forefront of this innovation, crafting backend systems and AI integrations that support Elliptic's copilot, enabling investigators to track fund flows, identify trends, and manage risk in real-time.We are seeking a dedicated Backend Software Engineer to join our team and contribute to the design and implementation of APIs, workflows, and services that facilitate these capabilities.Your Impact:As a Software Engineer within the Automation Forge team, you will play a key role in designing and delivering robust, scalable services that underpin Elliptic’s copilot and other AI-enhanced functionalities.Collaborating with product managers, frontend engineers, and your technical lead, you will transform complex blockchain data into intuitive, user-centric solutions that assist compliance teams in tracing fund flows, revealing intricate patterns, and responding to risks with agility and assurance.By working collaboratively across various disciplines, you will contribute to the development of impactful features while consistently enhancing the quality, reliability, and usability of our platform. Your efforts will be instrumental in advancing Elliptic’s mission to create safer, more transparent, and efficient cryptocurrency markets.Your Responsibilities:Design, develop, and maintain backend services and event-driven systems utilizing TypeScript and Node.js.Build APIs and workflows that seamlessly integrate AI and LLM frameworks to enhance Elliptic's copilot and other intelligent features.Optimize and query data models across both relational and NoSQL databases.Work alongside cross-functional teams to bring features from concept to production.Participate in technical design reviews, planning sessions, and code reviews to continually enhance system quality.Contribute to infrastructure and observability practices within the team, ensuring shared responsibility for the performance of services in production.Your Qualifications:3–6 years of backend engineering experience specifically with TypeScript / Node.js.Strong API design expertise — you have developed and maintained production APIs and understand how to interface with external systems.Proficiency in data modeling — comfortable designing, optimizing, and querying data across various databases.Excellent collaboration skills — able to work effectively with diverse teams and communicate technical concepts clearly.

Join xAI as a Backend Engineer, where you will play a vital role in building robust production systems that support grok.com and our API. We are looking for a highly motivated individual with expertise in scalable infrastructure and a passion for problem-solving. Your experience with Rust or C++, along with your ability to design and maintain distributed systems, will be crucial as you contribute directly to our mission of advancing AI technologies. Strong communication skills and a commitment to excellence are essential in our collaborative environment.

Who We AreLightning AI is the innovative force behind PyTorch Lightning, established in 2019. We provide a comprehensive platform designed to streamline the development, training, and deployment of AI systems, effectively bridging the gap between research and production.Our merger with Voltage Park, a neocloud and AI Factory, empowers us to combine developer-centric software solutions with economical, large-scale computing capabilities. We equip teams with essential tools for experimentation, training, and production inference, ensuring built-in security, observability, and control.We cater to solo researchers, startups, and large enterprises alike, operating globally with offices in cities such as New York City, San Francisco, Seattle, and London. Our efforts are supported by notable investors including Coatue, Index Ventures, Bain Capital Ventures, and Firstminute.What We’re Looking ForWe are seeking a skilled Backend Engineer to develop and enhance the Lightning AI platform across various components, from the frontend and CLI to API, billing, security, and integrations. You will take full ownership of key features, driving development from concept to production while collaborating with a talented team of engineers, product managers, and designers. This role offers the chance to create groundbreaking technology that will revolutionize the machine-learning ecosystem!This hybrid position is based in our London office with a requirement of 2 in-office days per week. The salary range for this role is $120,000 - $250,000.

About the Role vega is looking for an AI/Agent Engineer in London. This position focuses on designing and building intelligent agents that address complex challenges. Work will directly support the advancement of AI solutions across the company.

About Mistral AIAt Mistral AI, we harness the transformative power of artificial intelligence to simplify daily tasks, save precious time, and enhance learning and creativity. Our innovative technology is crafted to seamlessly integrate into the fabric of everyday work life.We are on a mission to democratize AI through high-performance, optimized, and cutting-edge open-source models and solutions. Our robust AI platform is tailored to meet the diverse needs of enterprises, whether on-premises or in the cloud. Our flagship offerings include Le Chat, your AI assistant for both life and work.We pride ourselves on being a dynamic, collaborative team deeply passionate about AI and its potential to reshape society. Our diverse workforce thrives in competitive environments and is dedicated to fostering innovation. With teams distributed across France, the USA, the UK, Germany, and Singapore, we embody creativity, humility, and a strong team spirit.Join us on this exciting journey as we shape the future of AI, making a meaningful impact together. Discover more about our vibrant culture at https://mistral.ai/careers.Role OverviewWe are on the lookout for passionate and talented Software Engineers to join our team. As a Backend Engineer, you will play a pivotal role in developing the core systems that power our key products: AI Studio, Le Chat, and Mistral Code. You will shape how users and developers interact with our AI platform at scale. Your focus will be on building reliable, high-performance backend systems and APIs that support millions of users and developers. Your contributions will directly enhance the user and developer experience, making it more engaging, efficient, and intuitive. We welcome engineers at all levels, from fresh graduates to seasoned professionals who are eager to learn, collaborate, and deliver impactful solutions.Key ResponsibilitiesBased on your expertise, you will engage in crucial components of our technology, including:Backend Development- Design, develop, and maintain scalable and robust backend features and APIs using modern frameworks.- Ensure high performance and reliability across our distributed systems.- Contribute to systems that support authentication, billing, AI tooling, and observability.

About UsAt Sierra, we are revolutionizing the way businesses engage with their customers through innovative AI solutions. Our mission is to craft exceptional, human-centric customer experiences. With our headquarters in San Francisco and expanding offices in London, Atlanta, New York, France, Singapore, and Japan, we are at the forefront of technology.Our corporate culture is deeply rooted in our core values: Trust, Customer Obsession, Craftsmanship, Intensity, and Family. These principles guide our actions and decisions, shaping a collaborative and empowering work environment.Led by co-founders Bret Taylor and Clay Bavor, Sierra is positioned for growth. Bret has an impressive background, having served as co-CEO of Salesforce and CTO of Facebook, while Clay has dedicated years at Google leading groundbreaking projects in AR/VR and product design.Your RoleArchitect and deploy state-of-the-art AI agents: You will be responsible for designing, developing, and launching high-performance AI agents that are pivotal to Sierra’s success, enhancing customer interactions across various sectors such as finance, healthcare, and e-commerce.Lead the Agent Development Life Cycle: Take full ownership of projects from inception to deployment and sustained enhancements, establishing best practices and ensuring the highest standards are met in AI development.Collaborate with industry leaders: Engage directly with top executives at major enterprises and dynamic startups, identifying their challenges and pioneering AI solutions that drive operational transformation.

Application Deadline: We are actively interviewing candidates and aim to fill this role promptly upon finding the ideal match. JOIN OUR TEAMBecome a vital part of our innovative AGI safety product team, where your contributions will transform intricate AI research into actionable tools that mitigate AI risks. As a Backend Engineer, you will collaborate closely with our CEO (who also serves as Head of Product), product engineers, and members of the Evals team to develop products that ensure AI agent safety at scale. Our current focus is on creating tools that monitor AI coding agents for potential safety and security failures.In this small, dynamic team, you will have a significant opportunity to shape both the technology and the team culture while quickly taking on responsibilities. This role is perfect for you if you are passionate about building solutions that enhance the safety of AI agents and thrive in a fast-paced environment, enjoying close collaboration with researchers.KEY RESPONSIBILITIESInfrastructure & Architecture- Design and implement scalable backend systems capable of real-time processing and analysis of substantial AI agent logs.- Build and maintain efficient data processing pipelines to extract, transform, and store agent trajectory data.- Architect database schemas and data models optimized for high-throughput writes and complex analytical queries.- Ensure system reliability by implementing robust error handling, retry logic, and graceful degradation strategies.- Monitor system performance and optimize bottlenecks to guarantee sub-second latency for critical monitoring operations.API Development- Develop secure, well-documented RESTful APIs that facilitate customer integration of our monitoring products into their workflows.- Implement authentication, authorization, and rate limiting measures to protect customer data and ensure efficient resource usage.- Build webhook systems and real-time notification services to alert customers about critical safety events.- Design user-friendly API interfaces that cater to developers while remaining adaptable to various customer needs.

Join Edra: Pioneering Solutions in Enterprise AIAt Edra, we're tackling one of the most challenging issues in enterprise AI: while AI models are inherently generic, company processes are uniquely specific. Our mission is to develop AI agents that comprehend how these processes operate and effectively manage their tasks.As a Series A startup, we are proudly supported by Sequoia and other prestigious venture capital firms. With our teams expanding in New York and London, we are a highly technical group comprising engineers, AI researchers, and strategists who all uphold a rigorous standard for talent. We believe that exceptional individuals are the cornerstone of our future success.Your RoleWe seek dedicated Backend Engineers who are passionate about the art of software development. Your focus will be on implementing strong typing, thoughtful API design, and robust data modeling. You will not be developing AI models; instead, you will construct the surrounding ecosystem: the platform, workflows, interfaces, integrations, and observability that render our AI applicable in real-world scenarios. As one of the early engineers at Edra, you will have the opportunity to influence not only the product but also the engineering culture, tooling decisions, and technical frameworks upon which our company is built.Our approach is intentional and thorough. There is no distinction between 'building it' and 'shipping it'—you will oversee the journey from conceptualization to deployment, taking full ownership of your outcomes. We prioritize thoughtful development over speed, striving for a balance between velocity and quality.Key ResponsibilitiesDesign and implement platform systems utilizing Python (FastAPI), including API contracts, database schemas, and infrastructureDevelop and sustain connectors, integrations, and data pipelines that link our platform to external systemsCreate internal libraries, tools, and interfaces that enhance the productivity of the engineering teamTake full ownership of your work by gathering context, managing dependencies, and driving tasks to completion independentlyEngage in multiple roles across the stack—design a schema in the morning, develop the API layer in the afternoon, and troubleshoot a deployment issue by day’s endParticipate in weekly product meetings, understand user interactions with your creations, and help shape future developmentsCollaborate daily with a small, elite team of engineers and AI specialistsHave a direct impact on the technical direction: select tools, establish patterns, and define conventions for the team

Join Duffel as a Backend Software Engineer and play a pivotal role in shaping the future of travel technology. We are seeking passionate individuals who thrive on solving complex challenges and are excited about creating scalable and efficient backend systems.

Join Our TeamAt Tracer, we are pioneering the development of autonomous AI agents designed to enhance production data pipelines. As a venture-backed startup, we are supported by a network of seasoned investors and industry leaders who share our vision of transforming AI into a critical component of enterprise software in the coming decade. Our compact team is composed of experienced professionals dedicated to delivering impactful solutions. Role OverviewWe are on the lookout for a Founding Senior Backend Engineer based in London. In this pivotal role, you will take ownership of building the core systems that convert production alerts into actionable root cause analyses (RCAs) and effective fix recommendations, targeting a select few high-value alerts.This position merges backend engineering with product development and customer-centric problem-solving, aiming to alleviate real-world production challenges with robust, reliable systems that engineers can depend on. Our Tech StackPython + LangGraph for multi-agent alert investigationRust for high-performance systemsClickHouse for managing high-volume event data and investigation historiesAWS + Terraform for self-sustaining infrastructureNext.js + TypeScript for an engaging frontend experience Key ResponsibilitiesAs the Founding Senior Backend Engineer, you will:Design and build the foundational alert, investigation, and root cause analysis (RCA) pipeline using Python.Develop essential systems including:Alert ingestion and normalizationContext enrichment and correlationProblem framing outputsHypothesis orchestration engineInvestigation execution runtimeInvestigation artifacts and reportingLead architectural decisions ensuring the system's observability, auditability, and reliability from day one.Work closely with the founders to deliver a focused set of high-impact alert types, while strategically expanding coverage.Create customer-ready documentation and reports that enhance user understanding and trust in the system.

At Docker, we are dedicated to simplifying application development, allowing developers to concentrate on what truly matters. Our remote-first team is global, united by a shared passion for innovation and exceptional developer experiences. With over 20 million monthly users and 20 billion image pulls, Docker stands as the leading tool for building, sharing, and running applications, trusted by both startups and Fortune 100 companies alike. We are in a rapid growth phase and just getting started. Join us for an exciting journey!As part of Docker's AI engineering team, you will play a pivotal role in shaping the future of containerized AI agents. Docker containers serve as the ideal platform to host and execute AI agents, providing isolation, portability, and reproducibility.You will contribute to Docker Agent, our open-source project (https://github.com/docker/docker-agent), enhancing it to empower developers to build, deploy, and scale intelligent agents using Docker's container technology.This position offers a unique greenfield opportunity to influence how developers utilize containers for AI agents at scale. You will collaborate with a team of experienced engineers and work closely with our sister teams focused on Ask Gordon and Docker's broader AI platform. This role combines cutting-edge AI techniques with container technology to address real-world developer challenges.Important Note: This position is only available to candidates currently residing in London (or within a reasonable commuting distance). We cannot make exceptions to this location requirement.

About usOwkin is a pioneering AI company dedicated to unraveling the complexities of biology. Our goal is to develop the first Biology Super Intelligence (BASI) by integrating advanced biological large language models, diverse patient data, and intelligent software. Central to our innovation is Owkin K, an AI copilot, and our specially fine-tuned LLM, Owkin Zero, which researchers, clinicians, and drug developers utilize to gain deeper insights into biology, validate scientific hypotheses, and accelerate the delivery of improved diagnostics and therapies.Please submit your CV in EnglishAbout the role:As a Senior AI Backend Engineer at Owkin, you will be instrumental in developing our leading Agentic AI product for biomedical researchers by merging robust engineering practices with state-of-the-art AI technologies. You will engage with a real-time system that integrates LLMs, tool-calling, and interactive UI elements, ensuring our users can interact seamlessly with intricate, domain-specific data.This position demands a balance of traditional engineering principles and innovative methodologies as you integrate LLMs and AI into our technology stack. If you are passionate about building and enhancing a dynamic product, this opportunity is tailor-made for you.Your expertise and experience will be vital in steering our multidisciplinary team towards strategic choices and empowering your colleagues.In particular, you will:Collaborate within a multidisciplinary team of product managers, designers, software engineers, machine learning experts, and biomedical scientists.Design, build, and maintain scalable, reliable AI systems.Drive technical decisions and provide context-aware solutions for AI systems in biological research.Leverage and pioneer evaluation methodologies to ensure continuous product enhancement.Experiment with cutting-edge industry solutions, including orchestration patterns, fine-tuning, specialized monitoring, feedback loops, and more.Lead core stack component development with a focus on sustainability, scalability, security, reliability, and performance.Foster team growth by sharing your expertise and mentoring colleagues through code reviews, technical discussions, and knowledge sharing.About you...

Role Overview The Trade Desk is hiring a Staff Software Engineer to help build advanced AI solutions. This London-based role centers on designing and implementing software systems that support and improve AI-driven products. What You Will Do Design and implement software systems for AI applications Work closely with teams across disciplines to expand product capabilities Support integration of new technologies into existing products Collaboration This role involves frequent collaboration with cross-functional teams to ensure AI systems are effective and integrate smoothly with other offerings.

At Scale AI, we’re not just creating AI tools—we’re leading the charge into the next frontier of enterprise AI. As organizations strive to leverage the capabilities of Generative AI, Scale stands at the forefront, offering innovative solutions that revolutionize workflows, automate intricate processes, and enhance efficiency for some of the largest enterprises in the world. Our Scale Generative AI Platform (SGP) provides essential services and APIs that empower businesses to effortlessly integrate AI into their operations at a production scale. We are on the lookout for a talented Backend Engineer to play a pivotal role in bringing large-scale GenAI systems into production. In this capacity, you will be responsible for constructing the core infrastructure that drives AI products for major enterprises—designing scalable APIs, distributed data systems, and resilient deployment pipelines that ensure production-grade reliability and performance. This is a unique opportunity to be at the epicenter of the GenAI revolution, tackling challenging backend and infrastructure obstacles that enable AI to function effectively at enterprise scale. If you are enthusiastic about influencing the deployment and scaling of AI systems in real-world scenarios, we would love to hear from you. At Scale, we don't just keep up with AI advancements—we drive them. With profound expertise in data, infrastructure, and model deployment, we are distinctly positioned to tackle the most challenging issues in AI adoption. Join us in shaping the future of enterprise AI, where your contributions will have a direct impact on how businesses operate, innovate, and thrive in the Generative AI era.

Join our dynamic team as a Senior Software Engineer specializing in Backend development. In this role, you will collaborate within our autonomous agile teams to craft the services that drive the Blacklane platform. Your contributions will enhance our back-office systems and address integration challenges for our business partners.Our Tech Environment: Our technology stack includes Ruby, Go, TypeScript, and Java, all structured using Domain-Driven Design (DDD). These services are deployed on Kubernetes and communicate via domain events using SQS and Kafka. We utilize a variety of data storage solutions including PostgreSQL, MySQL, Elasticsearch, Redis, and DynamoDB. Our cloud infrastructure is primarily based on AWS, with provisioning managed through Terraform.YOUR CHALLENGE:Address unique challenges to customize our products for specific markets.Maintain high standards through thorough test coverage, documentation, code reviews, and knowledge sharing.Dedicate time to optimizing performance, usability, and maintainability of the systems you oversee.Focus on personal development by acquiring new skills and technologies.Collaborate with a motivated, open-minded team committed to enhancing travel experiences for our guests.ABOUT YOU:You are proactive, curious, and a collaborative team player.You have at least 5 years of experience with two or more programming languages.You are proficient in at least one of the following languages: Ruby or Go.You possess knowledge of the HTTP protocol and have experience with REST APIs.You write high-quality, maintainable code and are familiar with the challenges of distributed systems.You are eager to learn more about event-driven architecture and domain-driven design.You have experience with Docker and containerized environments; knowledge of Kubernetes and Terraform is an advantage.

Join us at Docker, where we revolutionize app development, allowing developers to concentrate on what truly matters. Our remote-first global team thrives on innovation and enhancing the developer experience. With over 20 million monthly users and 20 billion image pulls, Docker stands as the premier tool for building, sharing, and running applications—trusted by both startups and Fortune 100 companies. As we rapidly expand, we're just getting started. Come aboard and enjoy this exciting journey!We are seeking a Principal Software Engineer (Docker Agents) to join our AI engineering team to shape the future of containerized AI agents. Docker containers provide the ideal environment for hosting and executing AI agents, ensuring isolation, portability, and reproducibility. You will work on our open-source project, cagent (https://github.com/docker/cagent), and enhance it to empower developers in building, deploying, and scaling intelligent agents utilizing Docker’s container technology.This is a unique opportunity to influence how developers harness containers for AI agents on a large scale. You will establish the technical vision, spearhead architectural decisions, and collaborate with engineers and leaders across Docker to integrate containerized agent capabilities into the developer experience.

About the TeamAt OpenAI, our Platform Systems team is at the forefront of innovation, merging advanced AI technologies with large-scale distributed systems. We create the engineering and research infrastructure essential for training OpenAI’s premier models on some of the world's most powerful, custom-designed supercomputers.Our dedicated team develops critical model training software, delving deep into the technical stack to enhance collective communication, optimize compute efficiency, refine parallelism strategies, and improve fault tolerance, failure detection, and observability. The systems we engineer are pivotal to accelerating OpenAI’s research, ensuring reliable and efficient training at the cutting edge of technology.We foster close collaboration with researchers throughout the organization, consistently integrating insights from across OpenAI to advance our training platform.About the RoleAs a Software Engineer specializing in Platform Systems, you will architect and develop distributed systems that enhance visibility into large-scale training workloads, ensuring their reliable operation at scale.Your responsibilities will include engineering failure detection, tracing, and observability systems to identify suboptimal or malfunctioning nodes, revealing performance bottlenecks, and enabling engineers to optimize extensive distributed training jobs. This infrastructure is vital for the functionality of OpenAI’s training stack and is continuously evolving to accommodate new use cases and increasingly intricate workloads.This position is central to our training infrastructure, merging systems engineering, performance analysis, and large-scale debugging.In This Role, You WillDesign and implement distributed systems for failure detection, tracing, and profiling large-scale AI training tasks.Create tools to detect slow, faulty, or erratic nodes, providing actionable insights into system performance.Enhance observability, reliability, and performance across OpenAI’s training framework.Diagnose and resolve challenges in complex, high-throughput distributed environments.Collaborate with systems, infrastructure, and research teams to elevate platform capabilities.Adapt and extend failure detection and tracing systems in support of new training methodologies and workloads.You Might Thrive in This Role If YouPossess a strong passion for performance, stability, and observability in distributed systems.Have experience with large-scale systems and are excited to tackle complex challenges in AI infrastructure.