Software Engineer, Backend (London)

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.

alten seeks a Backend Software Engineer for its Space Department in London. This role centers on developing software solutions that contribute to important projects and advance the team's technology. Role overview The Backend Software Engineer will work on building and maintaining systems that support the department's ongoing initiatives. The position involves collaborating with colleagues to deliver reliable and effective backend solutions. Location This position is based in London.

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

Role overview airapps is hiring a Backend Engineer for its London Metropolitan Area team. This role focuses on designing and building scalable server-side applications that support the company’s products and services. What you will do Work closely with colleagues across different functions to develop backend systems Contribute to the architecture and implementation of server-side features Help ensure backend solutions can scale and perform reliably Location This position is based in the London Metropolitan Area.

Join Us as a Senior Backend Software EngineerAt Freetrade, our mission is clear: to simplify investment for everyone. Investing shouldn’t be a convoluted or costly endeavor that deters individuals from maximizing their savings. We’re here to change that narrative!As we expand our team, we are searching for passionate individuals eager to redefine how our customers invest and enhance their wealth. If you are motivated by solving intricate problems and crafting innovative products, you will thrive in our environment.With a significant milestone approaching in 2026, following our transformative agreement to join the IG Group, we will continue to operate independently while benefiting from the resources and expertise of a leading player in the industry.This year marks a pivotal moment for us as we accelerate our product roadmap, introducing exciting new features including mutual funds, bonds, and family investment tools. We are also exploring the potential of AI to further enhance our customer experience.Our cloud-native infrastructure relies on Google Cloud Platform tools such as Firestore, Google Kubernetes Engine, PubSub, and Cloud SQL, enabling us to deliver a reliable and efficient platform built with Typescript. Here, your contributions will have a direct and positive impact on both customer experience and our overall business strategy. If you are eager to expand your technical expertise, contribute to new product development, and work in a creative, experimental atmosphere, this role is perfect for you!Why You Should Join Our Engineering Team?Become a vital part of a team that is shaping the future of investment. As a Senior Backend Software Engineer, you will lead the comprehensive development of impactful features, demonstrating your passion for independent problem-solving while scaling our next-generation, user-centric products. Our ideal candidate thrives in a dynamic, fast-paced environment and enjoys crafting innovative solutions.

Join our innovative team at reteam as a Backend Engineer! In this role, you will collaborate with cross-functional teams to develop robust backend solutions that power our applications.We are looking for an enthusiastic engineer who is passionate about creating efficient and scalable systems. Your expertise will contribute to enhancing our product offerings and improving user experiences.

Join Apron as a Senior Software Engineer - BackendAt Apron, our mission is to empower small and medium-sized businesses by ensuring their success. We understand that cash flow challenges often stem from the pressure of demand payments on business owners, which can hinder their ability to meet these obligations.We are bridging this gap by modernizing and simplifying the payment processing experience: from capturing invoices to issuing expense cards, and facilitating transactions—all in one seamless platform.As a rapidly growing company, we have expanded our team to approximately 100 talented individuals across the UK, Germany, Spain, and beyond. Backed by notable investors such as Index Ventures, Bessemer Venture Partners, Zinal Grow, and Tony Fadell, we have successfully raised $50 million to fuel our growth.Our Engineering CultureAt Apron, engineers play a pivotal role in our operations. Here's what you can expect:Customer-Centric Development: We utilize cutting-edge technology to create products that genuinely enhance our customers' lives.Ownership of Projects: From planning to execution, we take full responsibility for our work.Complex Financial Challenges: We embrace the intricacies of finance, navigating complex business logic and ensuring every detail is accounted for. Precision and attention to detail are paramount in creating a reliable product.Pride in Our Code: We prioritize building fast, secure, and scalable code that can grow with us.Integration of AI Tools: We leverage the best available technologies to ensure our product is genuinely beneficial.Your ResponsibilitiesWe are looking to expand our Card team, which has just launched. As a Senior Software Engineer, you will:Collaborate Across Teams: Work closely with Frontend Engineers, Product Managers, and Designers to develop innovative features.Design Robust Systems: Develop core financial integrations to ensure the security of customer funds and expedite transactions.Drive Innovation: Share your expertise with the team to foster innovation and proactively suggest improvements.

Join Nevis: Pioneering AI Wealth ManagementAt Nevis, we're on a mission to revolutionize wealth management through cutting-edge AI technology. Our innovative platform is designed to empower financial advisors, enabling them to enhance client relationships while our AI automates time-consuming workflows. As we build the future of wealth management, we have secured $40 million in funding from top-tier investors including Sequoia Capital, ICONIQ, and Ribbit, and are led by a talented team of ex-Revolut executives.Your Impact as a Software Engineer (Python)We are seeking a talented Software Engineer (Python) who is passionate about developing robust AI-driven platforms. In this key role, you will design and implement Python-based systems and services that drive intelligent workflows for leading financial firms. You will work on applied AI, data pipelines, model execution frameworks, and backend components that support our innovative AI products.If you thrive in a fast-paced environment, love creating production-grade AI solutions, and are eager to see your ideas come to life quickly, Nevis is the place for you. You'll join a world-class engineering team dedicated to building scalable AI systems.Your ResponsibilitiesDesign and enhance Nevis’ Python-based AI platform, enabling core workflows and agentic automation.Develop model orchestration, data processing pipelines, and execution runtimes for our applied AI features.Create scalable APIs and services that facilitate rapid development and deployment of AI systems.Architect systems for model inference, prompt execution, and multi-step agent reasoning.Maintain high engineering standards through clean code practices and CI/CD workflows.Collaborate with AI engineers, product managers, and designers to deliver impactful features used by thousands.Take ownership of greenfield AI platform components, from architecture to production.Engage in design and code reviews that shape Nevis’ technical future.

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.

Role Overview hook is hiring a Backend / Fullstack Engineer in London. This role involves building server-side applications and contributing to front-end features that improve how users interact with our products. What You Will Do Develop and maintain backend systems Work on front-end components to support a seamless user experience Participate in the full software development lifecycle, from initial idea through deployment Who We’re Looking For Comfortable working with both backend and frontend technologies Interested in taking projects from concept to launch Ready to collaborate with a team in London

Corgi builds insurance products for tech startups in the UK and EU, using AI-driven underwriting and a platform built on Django and Stripe. With $108M in funding and a licensed carrier status, the company focuses on new solutions tailored for the startup ecosystem. Role overview This backend software engineering position is based in London. Engineers here build and deploy products quickly, often working independently. The team values those who have taken projects from concept to launch, especially if they can point to live products or side projects with active users. What matters here Comfort with the pace and demands of a startup Proven ability to independently ship real projects Delivers results in hours or days, not weeks Works across the stack and adapts to new problems Shares strong opinions but stays open to better ideas Keeps ego low and focuses on real contributions How the team operates Quick decision-making, prioritizing progress over perfection Frequent product launches and process updates Short review cycles and regular releases High energy during launches, few quiet stretches Transparency in decisions and team communication Healthy internal competition that raises performance This is a build-focused role where steady contribution is expected. Behaviors that do not fit Office politics or gossip Taking feedback personally instead of using it constructively Introducing unnecessary bureaucracy Missing commitments or slow follow-through How to apply Send links to your GitHub, personal site, or live projects you have built and launched Do not send a CV Email your application to: sergio@corgi.com If you cannot show evidence of previous work, this role is not a fit Location and compensation London-based; on-site or hybrid options available Base salary ranges from £75,000 to £140,000, plus equity Compensation is based on proven ability to ship, not job titles

Join commercetools as a Senior Backend Engineer, where you will play a pivotal role in shaping innovative backend solutions using TypeScript. Collaborate with cross-functional teams to create scalable and resilient microservices that empower our clients to deliver exceptional digital commerce experiences.

Join our innovative team as a Backend Engineer! At Lever, we are committed to revolutionizing the way companies recruit and hire top talent. Our cutting-edge software is trusted by industry giants such as Netflix, Shopify, and Spotify. As we expand, we are on the lookout for passionate individuals to help us lead the charge in transforming talent acquisition.Lever has been recognized as the #1 place to work in San Francisco and is celebrated as one of the best workplaces across the United States. Our 'Leveroos' are our greatest asset, and we pride ourselves on fostering a culture that prioritizes our people. If you're ready to make a significant impact on how the world hires, this is the opportunity for you!

Join a Pioneering CompanyAt Palantir, we develop cutting-edge software that revolutionizes data-driven decision-making and operations. Our platforms empower partners to create life-saving medications, foresee supply chain challenges, locate missing individuals, and much more by connecting the right data with the right people.Role OverviewAs a Backend Software Engineer at Palantir, you will engineer scalable software that reshapes how organizations leverage data. You will actively participate throughout the product lifecycle—from ideation and design to prototyping and delivering production-ready solutions. Collaborating closely with both technical and non-technical team members, you’ll identify customers' challenges and create products that effectively address them. We promote cross-team interactions to foster the sharing of skills, context, and experiences, enabling you to gain insights into various technologies and product facets. Our engineers operate independently, making impactful decisions within a supportive community that encourages growth and development into strong technical contributors and engineering leaders.Your daily responsibilities will be dynamic, adapting to user needs and technical hurdles. One day, you might partner with other engineers to design a groundbreaking system that facilitates a new workflow; the next day, you could focus on optimizing performance for low-latency operational results.Our Product Development teams consist of small, agile groups of Software Engineers, each dedicated to specific product facets. These teams collaborate to build cross-functional capabilities, enhance user workflows, and consistently improve our software’s efficiency and reliability.We are seeking engineers who are enthusiastic about tackling real-world challenges and empowering both developers and end-users to maximize their potential. If you are driven to create reliable, high-performance, and scalable systems and to design robust APIs and primitives, this role presents a unique opportunity to significantly impact our products and the communities that utilize them.Unique Opportunity: Frontline ProgramFoundry Software Engineers may be selected for the Frontline Program, a distinct opportunity to engage directly with customers. In this short-term assignment, you will work alongside users to gain invaluable insights into product application and the challenges they encounter. Unlike standard engineering roles, Frontline involves tackling complex, ambiguous problems, empowering you to deliver impactful solutions across critical industries and institutions.

At Databricks, we are driven by a passion for empowering data teams to tackle some of the world's most challenging problems—whether it's revolutionizing transportation or accelerating medical advancements. Our mission is to build and operate the premier data and AI infrastructure platform, enabling our clients to harness deep data insights to enhance their businesses.Founded by engineers and deeply committed to our customers, we eagerly embrace every opportunity to confront technical challenges. From designing next-gen UI/UX for data interfaces to scaling our services and infrastructure across millions of virtual machines, we are just getting started.As part of our ongoing commitment, we are embarking on a multi-year journey to develop the best Lakehouse Platform. While we are building on a solid foundation, our aim is to create significantly improved products. This involves re-evaluating every component to deliver our customers the fastest, easiest to use, and most secure data platform for all their data workloads.As a Software Engineer, you will play a vital role as a founding member of our London site and the core team in our journey towards achieving the Lakehouse vision. You will be engaged in the complete development lifecycle and will embody the core values that define Databricks.Your Impact:Our backend teams tackle diverse challenges across essential service platforms. You may work on:Complex problems that encompass product and infrastructure components, including distributed systems, scalable service architecture, monitoring, workflow orchestration, and enhancing developer experience.Developing reliable, secure, and high-performance services and client libraries for managing vast amounts of data on cloud storage backends such as AWS S3, GCS, and Azure Blob Store.Creating product features that empower our customers to seamlessly store and access their data.Addressing reliability issues related to Lakebase.Proactively identifying downtime causes and systematically eliminating root issues.Assisting the organization in defining SLIs, achieving SLOs, and driving long-term reliability improvements.

We are seeking an experienced and passionate Senior Backend Engineer specializing in TypeScript to join our dynamic software engineering team at onrunning. In this pivotal role, you will lead the design and development of robust backend systems that power our innovative applications. You will collaborate closely with cross-functional teams to deliver high-quality solutions that meet the needs of our users. If you have a strong background in backend development, a love for building scalable systems, and a desire to drive technical excellence, we want to hear from you!

Affinidi is a London-based technology company working to reshape digital data ownership. The team creates tools that help individuals and organizations manage their digital identities, always with privacy and security as priorities. Their work centers on decentralized digital identity solutions, aiming to build a trusted network for digital credentials. This approach helps people and businesses exchange data and services safely across industries and borders. Role overview The Senior Backend Engineer (Rust) position focuses on developing backend systems that drive Affinidi’s vision of secure, user-controlled data management. This role requires strong, practical experience with Rust to build and maintain the core infrastructure behind Affinidi’s products. Engineers in this team work on complex backend challenges and are encouraged to find practical solutions to real-world problems. The work supports privacy-first, decentralized identity products that serve a wide range of users and industries. Location This role is based in London, England, United Kingdom.

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 Palantir Technologies as a Senior Backend Software Engineer focused on Infrastructure. In this crucial role, you will design and implement robust backend systems that power our cutting-edge software solutions. Collaborate with a talented team to develop scalable and efficient solutions that meet the needs of our clients.

Join a Pioneering CompanyAt Palantir, we are at the forefront of developing transformative software that empowers data-driven decisions and operations. Our platforms enable partners to revolutionize industries by facilitating groundbreaking discoveries in healthcare, enhancing supply chain resilience, and aiding critical social initiatives.The OpportunityAs a Backend Software Engineer at Palantir, you will play a crucial role in crafting scalable software solutions that redefine organizational data usage. You will engage in every phase of the product lifecycle—from conceptualization and design to prototyping and delivery. Collaborating closely with both technical and non-technical team members, you will gain deep insights into customer challenges and develop innovative solutions. Our culture promotes cross-team collaboration, allowing you to broaden your technical expertise across various technologies and product domains. You'll work independently while receiving support from a vibrant community that encourages your growth as a technical contributor and engineering leader.Our Product Development teams consist of small, focused groups of Software Engineers, each dedicated to distinct product facets. The infrastructure teams specialize in the foundational layers of our software stack, emphasizing database technologies, distributed systems, large-scale data architectures, security, and application infrastructure. As an infrastructure Software Engineer, you will produce high-quality code that underpins Palantir Foundry and Gotham, ensuring they are performant, secure, and scalable. Your work will empower critical applications utilized by researchers, engineers, analysts, and forecasters across the globe.We seek engineers who are passionate about tackling real-world challenges and enhancing the productivity of both developers and end-users. If you are driven to create reliable, high-performance systems and robust APIs, this position offers a unique chance to impact our products and their users significantly.Exclusive Learning ExperienceSuccessful candidates may also participate in Frontline, a distinctive program that embeds engineers directly with customers. This short-term assignment provides invaluable insights into user experiences and the complexities our customers encounter, differentiating it from traditional engineering roles.