C++ and Python Developer at LMAX | London

Join Mustard Systems, where we harness the power of statistical modeling to analyze sports events, enabling accurate predictions of future outcomes. By leveraging our proprietary datasets, sophisticated statistical models, and custom software solutions, we aim to deliver precise forecasts in the world of sports.We prioritize speed and real-world impact over perfection in code. If you are an engineer who excels at rapid problem-solving and thrives in a flexible, outcome-oriented environment, you'll find a home with us.Your Role:Enhance our connections to new liquidity providers using advanced web scraping and reverse engineering techniques.Create and maintain low-latency, real-time data feeds to support trading strategies based on extracted data.Improve system visibility for teams to gain insights into integration challenges and enhancements.Our agile methodology allows us to adapt plans as new information and opportunities arise. Developers play a pivotal role, taking complete ownership of their software from design through development, testing, review, and production support.Key Responsibilities:Design and Implement Impactful Features: Develop features that align with our business objectives, ensuring high-quality code that delivers measurable value.Collaborate on Code Quality: Review and test peer code to uphold functionality, maintainability, performance, and quality standards.Production Support: Take charge of your team’s software in production, ensuring stability and prompt resolution of any issues.Cross-Team Collaboration: Partner with other development teams on cross-functional projects, working alongside traders and quants to devise the best solutions to real business challenges.Participate in Out-of-Hours Support for our Software Systems.Core Technology Stack:Languages: Python (3.10+), JavaScript/TypeScript for frontend tasks, and Go for select infrastructure.Tools: RabbitMQ and Kafka for messaging, PostgreSQL and Redis for data storage.Environment: Linux servers.Observability: OpenTelemetry, Prometheus, Grafana, and Zabbix.Required Qualifications:Solid experience in software development, particularly with Python.A degree in Computer Science or a related quantitative field from a recognized university.Excellent communication skills, enabling you to explain complex technical concepts to both technical and non-technical audiences.Strong decision-making skills, with an ability to make informed trade-offs in implementation and architectural decisions, balancing innovation with practicality.Experience with web scraping and related technologies is essential.

Join our innovative team at mustard-systems, where we develop tailored statistical models and probabilistic frameworks that accurately predict horse racing outcomes and optimize trading strategies. Your insights will directly influence our success, determining what to back, when, and how much.We are seeking a dedicated researcher to become a vital member of our quantitative team. In this role, you will enjoy significant ownership over your projects, making impactful decisions about what you build, how you approach it, and evaluating its effectiveness.If you have previously tackled challenging technical problems and are eager for more opportunities to apply your scientific problem-solving skills in a high-stakes environment, we want to hear from you.Your responsibilities will include building and refining our quantitative models. While our primary focus is on custom state space models, probabilistic frameworks, and neural architectures, we are open to exploring other methods if they yield better results. Understanding the data is just as crucial as modeling; you'll need to navigate its complexities and uncover untapped opportunities.You will be expected to articulate the rationale behind your modeling choices clearly, and we will encourage you to challenge our assumptions as well.As part of a small, ambitious team, you will grow your understanding of our product and domain, influencing research directions and the business decisions that stem from them. We are looking for someone who identifies problems, crafts solutions, and pursues tangible outcomes, rather than merely completing predefined tasks.

Join Updraft: Transforming Financial Futures!At Updraft, an award-winning fintech company authorized by the FCA, we are on a mission to revolutionize how individuals perceive and manage their finances. Our innovative platform automates everyday financial decisions, making it easier for users to handle credit cards, overdrafts, and loans. Experience a comprehensive spending overview across all financial accounts with Open Banking technology. Access a complimentary credit report with personalized tips to enhance your credit score. Leverage AI-driven financial planning tailored to help users manage expenses, eliminate debts, and boost credit ratings. Utilize intelligent lending solutions designed to lower the cost of credit. With over 800,000 users and a remarkable reputation within the UK fintech landscape, Updraft has helped individuals convert approximately £500 million in high-cost credit card debt into more manageable options, paving the way for better financial health. Rated 4.8 on Trustpilot, 4.8 on the Play Store, and 4.4 on the iOS Store by our satisfied customers. Recognized as a participant in the Technation Future Fifty 2025, a prestigious program that supports innovative startups on their journey to IPO. Featured in the Sifted 100 UK startups list for two consecutive years (2024 and 2025). We are seeking talented professionals to join us in our next growth phase, offering a unique opportunity to make a measurable impact. Expect a hybrid work culture that fosters collaboration across functional teams, generous learning budgets, wellness benefits, and the freedom to innovate and directly influence our customers' financial journeys.Become part of our commitment to building a fairer credit system!

Talan is looking for a Python Developer to join its London office. This position centers on building and maintaining applications for a variety of client projects. The work includes both new software development and ongoing support, with a strong emphasis on delivering solutions that meet business needs. Key responsibilities Design, develop, and maintain Python-based applications Collaborate with colleagues across different teams to achieve project objectives Take part in planning and implementing technical solutions Support existing systems and address issues as they come up Role overview This role involves hands-on development as well as troubleshooting and supporting live systems. Working in a collaborative environment, the Python Developer will contribute to projects that serve a diverse group of clients.

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.

Join Us at IntropicAt Intropic, we're pioneering the future of financial intelligence, merging deep market expertise with cutting-edge AI technology. Established in the financial hub of Canary Wharf, London, our mission is to distill complex data into clarity, precision, and actionable insights. Our culture is driven by values of truth-seeking, speed, and ownership, which shape our approach to building, learning, and collaboration. We prioritize integrity, impact, and a fast-paced environment where curiosity is not just welcomed, but vital. If you are eager for challenges, inspired by innovation, and ready to elevate your intelligence alongside a team of extraordinary minds, Intropic is the place where your ideas can flourish.Who We Are Looking ForAs a thriving fintech start-up with a proven range of products, we are now on a mission to create the next groundbreaking solution. We seek individuals who excel in tackling open-ended challenges across various disciplines. Our engineers engage in more than just standard tasks; your role may involve debugging Python, deploying infrastructure updates, engaging with product early adopters, and strategizing with team leaders. We value individuals over resumes; if this sounds like you, we would be excited to connect!

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 xAI as a Backend & Infrastructure Developer Experience Engineer, where you will enhance our internal developer tools to boost productivity across the organization. Your mission will be to build and optimize applications for debugging local environments, visualizing production data, and accelerating our CI pipelines. We are looking for a passionate and skilled engineer who thrives in a collaborative and innovative environment.

Application Notice: Please apply only to the position that aligns most closely with your skills and experience. If our team believes you are better suited for a different role, we will contact you regarding that opportunity.Position Overview:At Squarepoint Capital, we leverage Python to develop essential software that addresses pivotal challenges daily. You will engage with a diverse array of systems that drive our trading success, including core tools and frameworks, data pipelines that support predictive models in research and trading, and software products utilized globally by traders and researchers.Your collaboration with seasoned software developers and quantitative researchers will contribute to the ongoing expansion of our investment business, tackling problems at scale, while also providing a unique opportunity to learn from some of the industry's most talented professionals.

Corgi is an AI-driven insurance company designed for tech startups. With $108 million in funding and a licensed carrier status, Corgi is expanding into the UK and EU. The core platform runs on Django, integrates Stripe for payments, and uses AI for underwriting. Role overview The team is hiring a Backend Developer in London. This is a hands-on position for someone who enjoys building and launching products quickly. Developers who have taken projects from concept to live deployment, whether as side projects, weekend builds, or products used by real users, will feel at home here. What matters here Experience independently building and launching real-world projects Ability to deliver results in hours or days, not weeks Comfort working across the stack and adapting to new problems Openness to better ideas, even with strong technical opinions Low-ego, outcome-focused mindset Drive and energy for a rapid startup pace How the team works Decisions are made quickly, without waiting for perfection New products and improvements ship regularly, not just quarterly Ship-and-iterate approach instead of lengthy reviews High intensity expected during both launches and quieter periods Transparency is standard; decisions are made openly Internal competition pushes everyone to improve This role is for builders who want to contribute actively. Behaviors that don’t fit Office politics, avoiding responsibility, or gossip Taking feedback personally instead of using it to improve Complicating processes instead of simplifying them Missing commitments or not following through promptly How to apply Send links to your GitHub, personal website, or live projects you have launched CVs are not required Email applications to: sergio@corgi.com If you cannot show shipped work, this may not be the right fit Location and compensation Role based in London; on-site or hybrid options available Salary: £75,000 to £140,000 plus equity Compensation reflects proven shipping ability, not job titles

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.

We are seeking a talented Full Stack Developer to join our dynamic team at Vitol, where you will collaborate closely with various business lines. This role presents a unique opportunity to engage with both technical and non-technical experts to create innovative solutions and full-stack applications that are utilized globally across numerous commercial and operational desks. Your contributions will significantly influence decision-making through the development of cutting-edge solutions.In this role, you will play an integral part in transforming our existing application landscape. Your ability to swiftly comprehend business needs, communicate effectively, work autonomously, and rapidly prototype and iterate on new and existing requirements will be essential in delivering state-of-the-art solutions that empower our commercial teams.As a Full Stack Developer at Vitol, you will exemplify:Rapid Prototyping: Collaborate closely with operations and commercial teams to construct and support market-driven business development applications and enhance existing tools by swiftly iterating based on user feedback to create actionable, value-adding solutions.Project Management: Analyze ongoing business and user requirements while independently managing project lifecycles from start to finish within the team.Innovation: Propose innovative and reliable technical solutions that enhance existing processes or uncover new opportunities for the business.Platform Expertise and Integration: Develop a comprehensive understanding of Vitol's Management Information Systems (MIS) platforms and tools, including their functionalities and capabilities, to ensure their success.

Galaxy Digital Services develops digital asset solutions at the intersection of finance and technology. The company invests in data center infrastructure to support AI and high-performance computing, focusing on blockchain and digital asset innovation. With a global presence and a team led by CEO Michael Novogratz, Galaxy serves institutions, startups, and developers navigating the digital economy. What you will do This Backend Java Developer role is part of the Lending technology team in London. The position centers on building and maintaining crypto lending systems. Core responsibilities include: Developing and enhancing lending infrastructure Working on collateral management features Implementing interest calculation logic Building liquidation processes Integrating with blockchain networks and traditional financial systems Who succeeds here The team values engineers who work independently, solve complex problems, and take ownership of their projects. Analytical skills and a drive to resolve challenges are important for this position. Our core values Strive for Excellence Be Selective to Achieve Effectiveness Maintain High Alignment with Loose Coupling Engage in Transparent Disagreements Support Independent Decision-Making Build Exceptional Teams

Job Title: Python Developer – Front Office R&D Trading SystemsLocation: London, UKEmployment Type: Permanent or ContractAbout MARGOMARGO is a cutting-edge consultancy providing invaluable IT expertise to the financial services sector. We excel in complex Front Office environments where software engineering, quantitative analysis, and production stability converge. Our specialists collaborate closely with trading and research teams to enhance real-time trading platforms, pricing models, and analytical systems.The RoleAs a key member of our Front Office R&D and Trading Technology team, you will be responsible for designing, maintaining, and evolving the ecosystem utilized by traders and quantitative analysts. This role involves 70% Development & Engineering and 30% Production Support, allowing you significant ownership over the platform.The environment is dynamic and characterized by rapid iterations, direct trader interaction, and stringent reliability standards. You will primarily work with Python to develop essential frameworks, analytical libraries, and monitoring tools.Key ResponsibilitiesDevelopment & Engineering (Approx. 70%)- Design, develop, and maintain core libraries and frameworks in Python.- Collaborate with traders and research teams to gather requirements for new analytical and trading tools.- Enhance the performance, scalability, and maintainability of the Python platform.- Upgrade existing monitoring, analysis, and control tools to support research workflows.Support & Production (Approx. 30%)- Provide L1/L2 support to Front Office users to ensure system stability during market hours.- Investigate and resolve production incidents promptly.- Develop tools to enhance system reliability and operational efficiency.- Contribute to the evolution of performance-sensitive, low-latency setups.RequirementsEssential Skills:Strong Python Proficiency: Deep expertise in core Python development and performance-oriented coding.Linux/UNIX: Robust knowledge of Linux environments for production and debugging.Database Skills: Proficiency with SQL and relational databases.Production Experience: Capacity to perform under pressure and strong troubleshooting and analytical abilities.Communication: Clear communication with a structured approach to problem-solving.Valued (but not mandatory):Experience in Front Office R&D or Electronic Trading environments.

Join Our Team at WintermuteWintermute is a pioneering technology unicorn and a leading player in the algorithmic trading space, focusing on digital assets. We excel in providing liquidity across major cryptocurrency exchanges and trading platforms, deliver comprehensive OTC trading solutions, and actively support renowned blockchain projects as well as traditional financial institutions making their foray into the crypto realm. Additionally, our Wintermute Ventures division invests in promising early-stage DeFi projects.Founded in 2017, Wintermute has adeptly navigated the evolving landscape of the industry. Our culture merges the technology standards of high-frequency trading firms in traditional markets with the innovative spirit and entrepreneurial environment found in tech startups. We are passionate about the transformative power of blockchain and are committed to fostering a compliant and forward-thinking market in the digital asset space. For more insights, click here.Position OverviewWe are in search of a skilled Core Developer to join our dynamic development team. This role offers the opportunity to work within a focused, high-performing group that has a wide-reaching impact across various business sectors. The ideal candidate will be pragmatic, dedicated to producing clean and efficient code, and possess strong interpersonal skills, as collaboration with traders, C++ developers, quantitative researchers, and the DeFi Team is essential. While prior experience in crypto or finance is not a prerequisite, a solid technical foundation and the right mindset are crucial.Our primary services are developed in Python, though we also maintain high-performance infrastructures utilizing C++. We prioritize using the latest versions for both languages. Our systems operate on Linux, utilize PostgreSQL for database management, and incorporate several custom in-house solutions tailored to address challenges common in high-frequency trading.

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 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 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.

Join our dynamic team at Axicorp Financial Services as a Backend Developer. In this role, you will leverage your expertise to develop robust backend services that drive our financial applications. Your contributions will directly affect our efficiency and the overall customer experience.We are looking for a candidate with a passion for technology and a commitment to excellence. If you thrive in a fast-paced environment and enjoy solving complex problems, we want to hear from you!