Backend Engineer at 9fin | London

Join Herondata as a Principal Backend Engineer and lead the charge in developing robust backend architectures. You will collaborate with cross-functional teams to design, implement, and optimize scalable solutions that support our mission of providing top-tier data services. Your expertise will drive innovation and enhance our platform's performance, ensuring we remain at the forefront of the industry.

(Applicants must be based in London, UK)About the RoleWe are on the lookout for talented and driven Full Stack Engineers to join our innovative team at Herondata. As a pivotal member of our fast-growing AI startup, you will play a crucial role in crafting elegant technical solutions that address our customers’ diverse challenges. If you are passionate about delivering high-quality code and are eager for a rewarding new challenge, we want to hear from you!Key ResponsibilitiesIn this hands-on role, you will focus on developing products that provide real solutions for our customers. Your responsibilities will include:Creating, maintaining, and enhancing backend services and APIs.Developing and designing new UI and web components.Integrating with third-party services and AI models.Assisting in bug triage, investigating production incidents, and contributing to postmortems and root cause analyses.Engaging in code reviews and collaborating with both technical and non-technical teams and stakeholders.What We SeekOur ideal candidate will:Be passionate about building impactful solutions: You enjoy shipping code rapidly, valuing MVPs and customer outcomes more than perfection. You take ownership of the deployment of your work.Excel at solving complex technical challenges: You can break down problems into simple, effective solutions, maintaining a fact-based and thoughtful approach.Focus on scalability: You prioritize impactful action while ensuring scalable infrastructure and engineering processes. You bring innovative practices to improve our systems.Contribute within our tech stack: We are currently utilizing Python/Flask/FastAPI for the backend, Terraform/GCP/AWS for infrastructure, and React/JavaScript/TypeScript/Vercel for the frontend. Your ability to contribute and enhance our stack is essential.

Product ManagerJoin Herondata as a Product Manager and be part of a revolutionary team transforming automated document workflows. You will take charge of a product vertical from inception to delivery, ensuring we create features that drastically reduce manual workloads for our clients. If you possess a passion for customer engagement, rapid deployment, and thrive at the intersection of artificial intelligence and financial services, we want to connect with you.The OpportunityEvery day, countless small businesses seek funding. Brokers inundate underwriters with an array of documents—bank statements, tax returns, application forms—often in various formats. This labor-intensive process can cost valuable deals to competitors if underwriters can't keep pace.Herondata is here to change that narrative. We streamline the process by automatically reading emails, classifying documents, extracting and enriching data, applying evaluation rules, and delivering ready-to-use outputs directly into clients' CRMs within minutes. With over 150 funders, brokers, fintech companies, and insurers currently relying on our solutions, we are in a phase of rapid growth, continuously adapting to new challenges and markets.We are looking for a Product Manager to spearhead one of our key verticals. You will engage with customers, define product specifications, collaborate with engineering to launch features, and assess their effectiveness. This role provides you with direct influence over the product roadmap and the autonomy to make impactful decisions, giving you a unique opportunity to solve real-world problems.Your ResponsibilitiesOwn a product vertical: Lead discovery phases, draft specifications, prioritize the backlog, and collaborate with engineering to deliver enhancements that resonate with customers.Be the voice of the customer: Establish strong relationships with customers in your vertical, conduct regular feedback sessions, and convert their challenges into product initiatives.Ship and iterate: Act swiftly, measure impacts, and refine. We prioritize results over processes—a feature that positively influences a metric is far more valuable than a perfectly crafted specification that remains unimplemented.Set product strategy: Develop and communicate a transparent product strategy rooted in customer insights, competitive analysis, and business outcomes.Collaborate across the organization: Partner closely with engineering, deployment, sales, and customer success teams to ensure successful implementation of our offerings.

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 CoreWeave as a Principal Engineer!At CoreWeave, we are redefining the cloud landscape for AI innovation. Our platform is tailored for trailblazers, offering cutting-edge technology and a collaborative environment designed to empower innovators to construct and expand AI solutions with assuredness. Serving leading AI labs, startups, and global corporations, we blend exceptional infrastructure performance with extensive technical know-how to expedite breakthroughs and transform compute power into actionable capabilities. Since our founding in 2017, we have proudly transitioned to a publicly traded entity (Nasdaq: CRWV) as of March 2025. Discover more at www.coreweave.com.As a Living Wage accredited Employer, we prioritize fair compensation for all our employees.

Join Aircall, a revolutionary unicorn in the AI-powered customer communications sphere, trusted by over 22,000 companies globally to enhance revenue, expedite issue resolution, and empower customer-facing teams. We are transforming the landscape of customer communications by integrating voice, SMS, WhatsApp, and AI into a unified workspace.Our growth is driven by a straightforward principle: to enable teams to work smarter, not harder. Our AI Voice Agent automates routine calls, while AI Assist simplifies post-call tasks, and AI Assist Pro provides real-time insights, allowing individuals to excel in their roles. This synergy results in increased revenue, quicker resolutions, and scalable teams.Headquartered in Paris, with a solid presence in North America anchored in Seattle, Aircall also has teams in vibrant cities such as Madrid, London, Berlin, San Francisco, New York City, Sydney, and Mexico City. Our product is beloved by customers, and we are rapidly scaling, supported by top-tier investors and continuous AI advancements across multiple product lines.At Aircall, you'll become part of a dynamic company. We are ambitious, focused on product development, and execution-oriented, with a clear impact, swift decision-making, and genuine growth opportunities.Our Work Culture at Aircall: We prioritize customer satisfaction, leverage data for decision-making, and are dedicated to delivering significant outcomes. We cherish ownership, continuous improvement, and thoughtful agility. If you thrive in a collaborative, fast-paced environment where trust and impact are essential, you will thrive here.Position Overview:As a Senior Backend Software Engineer, you will take charge of designing, developing, deploying, and maintaining essential features that enhance customer value on our voice platform.You will be expected to advocate for best practices, mentor team members, and contribute to the broader Engineering community as part of your daily responsibilities.Quality, excellence, and agility are at the core of our delivery process, and you will play a pivotal role in elevating these standards.Utilizing a diverse array of backend technologies tailored to specific needs, all hosted on AWS, we create resilient services that deliver added value on top of voice while fully integrating with our customers' critical business tools (CRM, Helpdesk, E-Commerce, etc.).

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.

At Intercom, we're revolutionizing customer service through our advanced AI solutions. Our flagship AI agent, Fin, empowers businesses to deliver exceptional customer experiences, ensuring they're always available to assist users. When combined with our Helpdesk, Fin forms the Intercom Customer Service Suite, a comprehensive solution for addressing complex customer queries that require a personal touch.Since our inception in 2011, we have gained the trust of nearly 30,000 businesses globally, setting the standard for customer service excellence. Our commitment to innovation drives us to push boundaries and deliver unparalleled value to our clients.What’s the opportunity?As a Principal Engineer at Intercom, you'll take the lead in defining and executing key strategic initiatives. This role offers you the autonomy to impact the engineering organization significantly. You'll be responsible for developing both back-end and front-end systems, collaborating closely with designers, product managers, researchers, and data analysts. Additionally, you'll mentor and coach fellow engineers while partnering with Group Engineering Managers on technical strategy and leadership.What will I be doing?In this role, you will:Utilize your domain expertise to lead pivotal projects within our R&D organization.Provide insights on project progress, risks, and challenges to guide resource allocation and prioritization effectively.Contribute to our technical architecture, ensuring our systems scale to meet growing customer demands.Prioritize agility alongside scalability and availability, with a focus on continuous deployment and incremental releases.Engage in all software development phases, including ideation, prototyping, design, and implementation, balancing hands-on development with architectural leadership.Leverage state-of-the-art tools to enhance productivity and streamline problem-solving.

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.

About 9fin9fin is a cutting-edge AI platform revolutionizing the global debt markets, which represent the largest asset class exceeding $145 trillion.The landscape of debt markets is extensive, global, and essential, yet it often relies on disjointed data, PDFs, and manual processes. 9fin transforms this outdated infrastructure by providing a unified platform that consolidates proprietary credit data, in-depth analysis, and efficient workflows across international markets.Currently, 9fin empowers over 300 prestigious institutions worldwide, including leading banks, asset managers, private equity firms, law firms, and consulting advisors. The company is experiencing rapid growth, particularly in the US, with exceptional retention rates driven by robust workflow adoption.We are at a pivotal moment. With a validated product-market fit and strong global demand, 9fin is propelling towards becoming the definitive platform for debt markets globally.What You'll Work OnAs a Senior Backend Engineer on our Structured Credit team, you will contribute to the development of our market-leading CLO product and assist in the launch of a new vertical.Our team is dedicated to making a significant impact, leveraging technology to create value for the business. While we have overarching business goals, we enjoy the autonomy to define our team objectives and determine our success metrics. We uphold accountability and proactive behaviors such as ownership.Lead projects within a cross-functional team by defining and designing systems, building proof of concepts, and delivering new service functionalities—including APIs, data processing, and automation—while collaborating with Product and Clients.Engage in backend development and engineering primarily on the services and web applications hosted on the 9fin platform.Play a crucial role within project teams as a senior individual contributor, conducting code reviews, mentoring fellow developers, and participating in early research and experimentation with new technologies to provide insights for new features and products.Continuously enhance the 9fin codebase by seizing opportunities to automate, refactor, and document processes when it has the most significant impact.Work across diverse web platforms involving complex financial data modeling, intricate access control logic, environmental data capture, integration of ML/AI prediction services, and data visualization.

About JuniorAt Junior, we are on a mission to revolutionize the investment research landscape with innovative LLM-powered tools designed specifically for private market investors. Our clientele includes some of the world's leading private equity and consulting firms, collectively managing billions in annual investments. As a profitable and bootstrapped enterprise, we have grown our team to 24 talented individuals across our London and NYC offices, and we achieved a remarkable 10x revenue growth in 2025.Discover more about our mission and values here. Role DescriptionAs our first dedicated Backend Engineer focused solely on our internal go-to-market and operations stack, you will play a pivotal role in shaping our technology framework. Your responsibilities will include:Crafting an AI-first tech stack from the ground up, influencing infrastructure decisions and priorities.Rapidly deploying internal tools and receiving immediate feedback from your team members, who will quickly become your strongest advocates!Developing and managing our data warehouse and internal data architecture.Engaging in innovative projects that leverage LLMs, automation, and advanced agent technologies.Cultivating our engineering culture. Sample Set of ProjectsUser Health Reporting + CRM Data Quality: Automate data pipelines to enhance metrics visibility in BI dashboards and ML evaluations, while establishing alert systems for risk signals.User Feedback Integration: Develop a tool that summarizes user feedback calls, prioritizes feature requests, and communicates findings to our Product team.Billing and Invoicing: Implement complex B2B pricing models encompassing usage-based, seat-based, and platform fees, while automating financial reconciliation processes.Data Warehouse Development: Create a data warehouse to integrate product, CRM, and operational data, and generate tailored dashboards for different teams. About YouWe are searching for a backend/data engineer who...

Pelago stands at the forefront of virtual healthcare, specializing in Substance Use Management. Our comprehensive program offers personalized guidance, support, and treatment for individuals aiming to overcome challenges related to tobacco, alcohol, and opioid use. We cater to a diverse spectrum of substance use, from unhealthy habits to active disorders, ensuring that each member receives tailored care that aligns with their health, habits, genetics, and personal objectives. Our array of virtual services encompasses educational resources, cognitive behavioral therapy (CBT), and comprehensive medication-assisted treatment (MAT). Pelago empowers employers and health plans to provide accessible and effective solutions for substance misuse. Having successfully partnered with hundreds of employers and health plans, we have positively impacted over 750,000 lives. After recently securing our Series C funding with over $151 million raised from premier global investors, we invite passionate individuals to join our mission of transforming health outcomes.About Pelago Engineering:Our engineering team is composed of empowered, outcome-focused problem solvers who collaborate closely with product, design, and clinical teams to enhance member outcomes at scale.As AI reshapes the software development landscape, we are proactively refining our development processes to prioritize system design and impactful decision-making over rote implementation.How We Work:Outcome-driven: Engineers tackle substantial problems rather than merely building features. Success is evaluated based on learning, impact, and outcomes—not just speed.AI-native: We leverage AI throughout the software development lifecycle to expedite implementation, testing, and reviews, allowing engineers to concentrate on intent definition, behavior validation, and system resilience design.High autonomy, high accountability: Teams enjoy significant ownership of their domains, with autonomy translating to responsibility for quality, safety, and results.Cross-functional collaboration: Engineers work synergistically with Product, Design, Data, and Clinical teams, sharing responsibilities for discovery, experimentation, and delivery.Quality and safety are paramount: Our work is conducted within a regulated domain that directly impacts members, making reliability, observability, and correctness top priorities.What You’ll Do:Instead of traditional task lists, you will take full ownership of significant problem spaces from discovery through to delivery.

Backend Engineer About OutpostImagine a world where expanding your business globally is as easy as local sales. At Outpost, we are pioneering the AI-driven global trade engine, consolidating all the essential rules to facilitate international sales into a seamless infrastructure. Simply tell us what you’re selling, and we’ll guide you on how to sell it globally.Operating as the Merchant of Record or Tax of Record in over 58 tax jurisdictions, we take on full liability or just the tax layer. From analysis to setup, we absorb the complexities so you can focus on your business.Sell anything, anywhere, without compromise. The RoleWe are looking for a talented Backend Engineer eager to create complex financial infrastructures from the ground up. You will collaborate closely with our engineering leadership to implement payment flows, develop tax calculation engines, and build systems that power international commerce. Your insights will shape product and technical discussions, challenge existing assumptions, and help define our technical direction.Join us in constructing the infrastructure that empowers businesses to sell globally without the typical challenges. You will engage in payment processing, multi-currency ledgers, real-time tax calculations, merchant onboarding, and AI-powered compliance tools. Tackle challenging problems at real scale. What You’ll GetYes, the work can be intense, but you'll be building crucial financial infrastructure that manages hundreds of millions in transaction volume.Your contributions will significantly influence our technical direction, and you'll collaborate with a small team of experienced engineers, helping shape Outpost’s growth. If you're passionate about diving deep into payments, tax, and fintech infrastructure, this is the opportunity for you. What You’ll BuildPayment processing infrastructure capable of handling significant transaction volumesRobust ledger and reconciliation systemsTax calculation engines across multiple jurisdictionsReal-time transaction monitoring and risk management systemsMerchant onboarding and integration frameworksConnections with major e-commerce platformsAI/LLM powered taxation toolsAI/LLM driven fraud and risk management solutions What You’ll Do

Monzo Bank Ltd is seeking a Principal Backend Engineer to drive the design and development of scalable systems for its banking platform. This role plays a key part in shaping the technical direction of Monzo’s backend, ensuring that solutions are reliable and meet high standards of quality. Key responsibilities Lead the design and implementation of backend systems that power Monzo’s platform Establish and uphold coding and architectural standards across engineering teams Mentor engineers and support their growth in delivering maintainable solutions Champion best practices in software development and system design Technical leadership The Principal Backend Engineer will provide guidance to teams, influencing both immediate projects and long-term engineering strategy. Setting high standards and promoting effective practices are central to this position. Location This role is open to candidates based in Cardiff, London, or working remotely within the UK.

Corgi builds insurance solutions for tech startups, using AI to power underwriting and streamline coverage. Backed by $108M in funding and operating as a regulated carrier, the company is expanding across the UK and EU. The platform relies on Django, integrates Stripe for payments, and emphasizes new product development. Role overview This Backend Engineer role is based in London and centers on taking projects from concept to live launch. The team values engineers who build and ship products, not just maintain existing systems. Candidates who have delivered personal projects or launched products with real users will feel at home here. The environment suits those who prefer moving quickly and seeing their work in production without long delays. What matters here Independently developing and launching working products Shipping projects quickly, often within hours or days Comfort working across the stack and tackling new challenges Balancing strong opinions with openness to better solutions Low ego, with motivation driven by results Energy and drive to thrive in a startup setting How the team works Quick decision-making, prioritizing progress over perfection Frequent launches and iterative improvements Products ship and evolve, rather than stalling in review High intensity during launches, with steady momentum at other times Transparency and open decision-making are encouraged Internal competition is seen as a way for everyone to improve This is a hands-on role focused on building. Coasting is not an option. Behaviors that end the role quickly Engaging in office politics, avoiding accountability, or spreading rumors Taking feedback personally instead of using it to improve Choosing complexity when simplicity is possible Missing deadlines after making commitments How to apply Send links to your GitHub, personal website, or live projects Resumes are not accepted Email your application to: sergio@corgi.com If you cannot show delivered work, this role is unlikely to be a fit Location and compensation London-based, with on-site or hybrid options Base salary: £75,000 to £140,000 Equity is available The wide salary range reflects a focus on proven ability to ship, not job titles

Join Spotify as a Backend Engineer specializing in Personalization. In this dynamic role, you will develop and enhance backend systems that deliver personalized experiences to millions of users worldwide. Collaborate with cross-functional teams to design scalable solutions and implement cutting-edge technology that drives user engagement.

Begin your journey with us and advance your career.We are thrilled to present an opening for an accomplished and innovative Principal Façade Engineer to be part of our expanding and vibrant team. This role is perfect for a forward-thinking leader who excels in providing cutting-edge engineering solutions, fostering the development of talented professionals, and propelling business growth through strategic initiatives.Your role will involve:Leading the execution of a diverse portfolio of national and international projects across multiple sectors, ensuring an optimal balance of quality, feasibility, schedule, and cost.Securing project fees and negotiating contracts of various scales.Building and nurturing strong relationships with clients and referrers, encouraging the exploration of new business opportunities.Representing AECOM at industry events and conferences, highlighting our work and capabilities.Creating compelling proposals and leading successful presentations to win new projects.Mentoring a team of engineers, enabling them to realize their potential and enhance their skills.Overseeing the professional growth of engineers, including performance reviews, chartership, and essential management tasks to support team development.Managing façade team resources to meet technical and workload demands while pursuing personal skill development goals.Participating in R&D efforts to promote sustainable and energy-efficient design solutions.Collaborating with other teams within AECOM to further company-wide initiatives and multidisciplinary project delivery.Join us and grow:At AECOM, we offer a range of benefits tailored to support your well-being and career aspirations, customized to fit your lifestyle. Enjoy opportunities for career development, a flexible hybrid working model to ensure a work-life balance that suits you, access to technical practice networks, AECOM University, and volunteering days.

Join Beamery as a Principal EngineerAt Beamery, we are at the forefront of revolutionizing the HR technology landscape with our cutting-edge transformational AI platform. Our mission is to empower enterprise organizations to make informed and equitable talent decisions. By streamlining recruitment processes, enhancing internal mobility, fostering effective upskilling initiatives, and enabling agile workforce planning, we help our clients successfully manage the hiring and redeployment of over a million individuals each year.We are excited about our future as we deepen our integrations with major platforms such as SAP, Workday, Microsoft, and LinkedIn, enhancing our skills intelligence and allowing our customers to plan more effectively for the future. We leverage proprietary LLMs and knowledge graph technology to broaden talent access, make fairer decisions, and create opportunities at scale. Our company culture, built on trust, empathy, and transparency, ensures that every team member can bring their authentic selves to work.What You'll DoAs a Principal Engineer at Beamery, you'll tackle complex challenges that have significant impact across the organization. Collaborating with fellow engineers, you will help establish the architectural standards necessary for executing Beamery's strategic vision.Design and develop architectural solutions while drafting RFCs for initiatives that affect Engineering and beyond.Maintain your hands-on expertise by assisting teams in delivering scalable and high-performance software.Collaborate with Product and Engineering Directors to plan, scope, and size large-scale projects and features that span multiple teams.Partner with other Principal Engineers to refine and evolve the architectural vision that aligns with Beamery's strategy.

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.