Senior Fullstack Software Engineer

Join Octopus Energy, a pioneering force in the renewable energy sector, where we are redefining how energy is supplied in Britain. Our mission is to create a fully digital energy experience that empowers our customers while promoting sustainability. With a unique blend of innovative technology and a dedicated team, we have already become the largest energy supplier in the UK. As we expand, we are committed to accelerating the green energy transition through cutting-edge products and services that simplify the switch to renewable solutions such as heat pumps, solar power, and electric vehicles. At Octopus Tech, you will have the opportunity to take ownership of meaningful projects that positively impact lives—by reducing energy costs and enabling eco-friendly living. Collaborating with cross-functional teams, you will witness the immediate results of your work in the real world. As we build a lean and effective TechOps Engineering team, we seek a talented and experienced Full Stack Software Engineer to contribute to our vision. You will play a vital role in shaping the TechOps function, developing self-service technology that enhances our team's ability to leverage advanced tech solutions. TechOps represents a modernized approach to traditional IT, encompassing everything from first-line support to strategic planning. We are looking for someone who will help design and implement efficient, scalable, and robust solutions for our TechOps capabilities. If you are excited about making a difference in the renewable energy landscape, we would love to hear from you!

At Octopus Energy, we began with an audacious vision: to establish the UK's first fully digital energy supplier. Our journey has been driven by cutting-edge technology and a passionate team dedicated to customer satisfaction and the green energy transition. In 2025, we proudly became Britain's largest energy supplier.Today, we are rapidly expanding, developing innovative products that facilitate the transition to renewable energy. From simplifying the switch to heat pumps and solar energy to launching intelligent tariffs and scaling renewable energy generation, we tackle the most intricate challenges in the energy sector with agility, creativity, and a strong focus on customer needs. Our mission extends globally as we empower our international operations to share the successful innovations and experiences we've cultivated in the UK.Joining our Tech team means you’ll have the autonomy, diversity, and opportunity to design products that significantly impact individuals' lives—reducing energy costs, promoting sustainable living, and delivering exceptional customer experiences. You'll collaborate closely with teams from marketing, operations, and data, witnessing the real-world effects of your contributions.We invite you to apply for the position of Senior Backend Engineer within our Flexibility team.The Flexibility team is at the forefront of creating innovative products and tools that enhance energy adaptability. Our flagship product, Intelligent Octopus, automates demand management for 300,000 customers utilizing electric vehicles, home batteries, and smart heating devices. We save 2 million customers money through initiatives like Saving Sessions and Free Electricity Sessions while managing 568 MW of large-scale grid batteries to stabilize the energy system. The solutions we develop are utilized by millions, driving increased renewable energy usage and aiding in the decarbonization of global energy systems.We foster a flat organizational structure and a dynamic, open culture that nurtures innovation, flexibility, and creativity. At Octopus, we embrace authenticity—our team consists of talented individuals who achieve results while remaining true to themselves.If this opportunity resonates with you, we would be thrilled to connect.

Join Octopus Energy's dynamic TechOps team as a Senior TechOps Generalist. In this pivotal role, you'll leverage your extensive knowledge and experience to help shape our TechOps approach, providing unparalleled support to our employees while driving secure and efficient operational growth. You'll tackle diverse challenges, from first-line support to strategic planning, all within a cloud-first environment that prioritizes innovation and agility. Embrace the opportunity to influence organizational change and contribute to a world-class support service.

Join Octopus Energy Generation, a pioneering energy investment manager with over £7 billion in assets under management, as we strive to fast-track the transition to a net-zero energy landscape through strategic investments in clean energy infrastructure and transformative energy transition enterprises.Our diverse strategies encompass renewable generation, distributed energy, and various energy transition platforms, operating across multiple technologies and regions. To support our expanding portfolio of developmental and growth strategies, we are enhancing our internal tax capabilities to offer proactive and commercially-driven guidance across our fund structures and investments.We are on the lookout for a dedicated Tax Manager to join our OEGen Tax Team, reporting directly to the Head of Tax. This pivotal role will manage a specific segment of OEGen’s development funds and related structures. Unlike traditional tax roles embedded within platforms, this position resides within the fund management company, providing oversight throughout the complete fund lifecycle—from investment structuring and governance to portfolio holding structures and exit strategies.As the central tax lead for these funds, you will collaborate closely with investment teams, portfolio companies, finance departments, and external advisors across various jurisdictions. This role integrates fund-level tax strategy and governance with hands-on management of compliance, reporting, risk mitigation, and transaction execution.This position promises both breadth and depth, providing exposure to intricate international holding structures, varied operating models, and direct engagement with senior stakeholders across the organization.

Join the dynamic field sales team at Octopus Energy as a Venue Sales Representative! We are at the forefront of transforming traditional sales and marketing, focusing on innovative customer interactions that prioritize sustainability. Our mission is to make energy greener and better for everyone. At Octopus Energy, our customers are our top priority. We are seeking passionate individuals who share our commitment to delivering exceptional service! As a Venue Sales Representative, you will represent our brand with enthusiasm and showcase the incredible offerings of Octopus Energy to the public!

At Octopus Energy for Business, we are on a mission to transform the energy landscape for enterprises across the UK. Currently serving over 120,000 clients, we are just getting started!We are revolutionizing the energy market by eliminating middlemen, offering exceptional value, unparalleled customer service, and innovative products like Shape Shifters and Electric Match that empower businesses to manage their energy effectively.As a proud member of the Octopus Energy Group, we leverage cutting-edge technology, renewable energy, and flexibility to help companies reduce both costs and carbon emissions simultaneously.Now, we are eager to amplify our reach and let more businesses discover a superior alternative—and that’s where your expertise comes in.This is a hybrid role, requiring your presence in our London office typically three days a week.

Join Octopus Energy Generation, a leading energy investment manager with a portfolio exceeding £7 billion. Our mission is to propel the world towards a net-zero energy landscape by investing in innovative clean energy infrastructure and businesses focused on energy transition.Our investment strategies encompass renewable energy generation, decentralized energy solutions, and diverse energy transition initiatives across various technologies and regions. As we continue to broaden our portfolio of development-stage and growth strategies, we are enhancing our in-house tax expertise to deliver proactive, commercially-driven support across our fund structures and investments.We are on the lookout for a skilled Tax Manager to join the OEGen Tax Team, reporting directly to the Head of Tax. In this pivotal role, you will manage a specific group of OEGen funds that target investments in energy transition technologies and early-stage ventures, employing a venture capital/private equity investment strategy with a focus on the Asia-Pacific region and a variety of renewable energy assets.As the central tax authority for these funds, you will collaborate closely with investment teams, portfolio companies, finance departments, and external advisors across various jurisdictions. This role combines high-level tax strategy and governance with direct oversight of compliance, reporting, risk management, and transaction execution.This opportunity provides a unique blend of broad exposure and technical complexity, including early-stage equity investments, minority growth stakes, cross-border holding structures, and infrastructure assets across diverse jurisdictions in the Asia-Pacific region.

Location: Hammersmith, London Department: ITAssala Energy is a forward-thinking Oil and Gas Exploration and Production company dedicated to the sustainable development of its valuable assets in Gabon. We embrace a collaborative culture, champion diversity, and prioritize safety and integrity in every aspect of our operations.We are seeking a Senior Network Engineer to become a vital member of our IT team, responsible for maintaining and enhancing our global network infrastructure. In this role, you will ensure network stability, security, and efficiency across our operations while spearheading improvements and innovative solutions.

Join us as a Senior AI FullStack Engineer at a rapidly expanding AI FinTech company, where your expertise will help shape the future of finance.About Us:We develop and deploy AI-powered tools and intelligent agents throughout their entire lifecycle, from conception to production.Our systems are designed with AI at their core, not as an afterthought.Transform experimental concepts into production-ready features that impact real users.Take ownership of projects from problem identification to user adoption.Collaborate closely with engineering and product teams to seamlessly integrate AI into daily operations.Establish effective methodologies for implementing AI in production environments.We are on a mission to create an AI-native bank tailored for ambitious businesses.Your Contribution:Train and refine large-scale audio and multimodal models.Design and execute experiments focused on architecture, data mixtures, and training strategies.Develop and enhance audio data pipelines.Optimize inference speed, latency, and overall production readiness.Deploy models in end-to-end, low-latency settings.Create meaningful evaluation metrics that go beyond standard benchmark scores.Work collaboratively with both research and engineering teams.This role is hands-on, bridging the gap between research and real-world application.Technical Environment:PythonLarge Language Models (LLMs) and AI toolsPostgreSQL, BigQueryTypeScript, ReactAWS, GCPDocker, Terraform, GitHub(Detailed technical stack will be shared during the interview process)Your Expertise:5+ years of experience in building and deploying production systems.Full-stack or deep backend/platform engineering skills.AI-native mindset: you leverage AI in your daily work and think in terms of agents, workflows, and automation.Product-focused: your priority is user adoption over mere output.You excel at transforming complex challenges into scalable solutions.Bonus Skills:Experience in financial technology.Familiarity with cloud services and infrastructure.Contributions to open-source projects.

Founded in 2018, Causaly is at the forefront of transforming enterprise-scale scientific research through our innovative AI platform. Our technology empowers researchers to efficiently discover, visualize, and interpret biomedical knowledge, streamlining critical research workflows to tackle some of the most pressing health challenges of our time.We partner with leading biopharma companies and institutions, focusing on diverse use cases including Drug Discovery, Safety, and Competitive Intelligence. Visit our blog to learn how we enhance knowledge acquisition and decision-making: Blog - CausalyCausaly is proudly backed by renowned venture capital firms, including ICONIQ, Index Ventures, Pentech, and Marathon.

Join us in revolutionizing the energy sector at Kraken! We are on a mission to create a smarter and more sustainable energy ecosystem. As a TechOps Architect, you will play a pivotal role in defining and enhancing our TechOps strategy, ensuring we provide exceptional support to our employees while tackling complex challenges. With your engineering expertise, you'll help us navigate growth and implement transformative changes that benefit our entire organization.

Join Contentsquare, a pioneering experience intelligence platform, where we empower organizations to gain deep insights into their customers' digital journeys. Our innovative and scalable platform is designed for users across various expertise levels, making it easier to navigate the complexities of online interactions.As a global leader in experience analytics, we operate from 15 offices worldwide, committed to making a significant impact in the industry. We are seeking enthusiastic team members who are ready to contribute to our growth and success.At Contentsquare, we foster an inclusive work environment where every individual can thrive. Our community is built on values of courage, empathy, and intentionality, aimed at simplifying challenges for our clients, their customers, and each other.Note: Please be cautious of scam attempts impersonating Contentsquare. We do not request money or communicate through unsolicited messages. For further details, check our careers blog.Important Information:1. This is a software engineering position requiring a minimum of 5 years of relevant experience, particularly in TypeScript. While we utilize Large Language Models (LLMs), this is not a machine learning-focused role.2. The role is available as remote (in France, Spain, Italy, Poland, or Germany) or can be hybrid in our offices located in Barcelona, Paris, Milan, Munich, or Cairo.We are on the lookout for a Senior Fullstack Engineer (Applied AI) to engage in various innovative projects that harness the power of AI, especially leveraging LLMs. One of the key initiatives involves enhancing our AI CoPilot tool (currently exclusive to Heap) to broaden its application, allowing users with no prior experience in product or digital experience analytics to easily find answers through simple inquiries.Our rapid advancement in utilizing LLMs aims to streamline insights generation and simplify setup processes, among other enhancements. As our next Senior Software Engineer (Applied AI), you will play a significant role in product development and initial product iterations, participating in user interviews to validate product hypotheses.This position offers a unique opportunity to operate within a “startup-like” environment, where we swiftly transition from concept to proof of value, ensuring that our solutions deliver real benefits to our clients.

Role Overview Talos Trading is hiring a TechOps Engineer - System Administrator in London. This position plays a key part in supporting and improving the technology that powers our trading operations. The work focuses on maintaining and optimizing systems so trading platforms run smoothly and efficiently.

What We Do: Electric Car LeasingWhy We Do It: Greener. Fairer. Future.We are excited to invite applications for the role of Senior Account Manager to join our dynamic Customer Success team in London. This essential position is focused on cultivating the commercial success of our valued customer relationships.As a Senior Account Manager, you will assume full responsibility for a high-value enterprise portfolio, delivering our industry-leading EV salary sacrifice scheme. Your key responsibilities will include developing multi-year growth strategies, mitigating commercial risks, and ensuring maximum scheme adoption along with long-term client retention.This role demands a strong presence, exceptional commercial insight, and a steadfast dedication to transforming our mission of sustainable transport into measurable outcomes for both our corporate partners and Octopus Electric Vehicles.Please be advised that a valid UK driving licence is required for this position.

Join Our Team at CapiCapi is revolutionizing the way businesses in emerging markets manage their international supplier payments—making it simple, swift, and equitable.With over $18M in support from leading investors including Creandum, Y Combinator, General Catalyst, and influential figures from Revolut, Checkout, Stripe, and Remitly, we are dedicated to establishing the robust financial infrastructure that emerging markets truly deserve.Our commitment to facilitating global trade empowers local enterprises to accelerate growth, create job opportunities, and enhance prosperity in their communities.Our mission is to uplift GDP in emerging markets by fostering a more equitable and accessible global financial system. We aim to streamline the payment processes for importers, enabling businesses to expand swiftly and act as catalysts for national prosperity.Our dynamic team of approximately 80 individuals, spread across 10 countries, embodies ambition and a results-driven mindset, striving to make a meaningful impact in the world. We are eager to welcome new talent to our team!Explore Capi's mission & values.Role OverviewAs a Senior Fullstack Engineer, you will be part of a compact, high-performing team of engineers and product leaders responsible for scaling our platform and amplifying our impact.From day one, you will collaborate closely with our founding team based in London and Paris, influencing the product vision and shaping the technical architecture of our solutions. This role is pivotal in developing technology that addresses customer challenges as we grow our offerings and enhance our footprint in emerging markets.Empathy and curiosity are essential to uncovering the root causes of problems, along with the creativity to devise solutions that harmonize impact, effort, and user satisfaction.Key ResponsibilitiesEngage in the product lifecycle from conception through to UI design, backend logic, deployment, feedback gathering, and performance measurement.Communicate effectively both internally and externally regarding new features, gathering feedback prior to implementation and articulating them upon launch.Determine and oversee delivery milestones, ensuring alignment between engineering and product priorities.

Octopus Legacy is seeking a Finance Manager to lead financial operations at its London office. This position offers the chance to shape finance processes for a company committed to modernizing a traditional sector and supporting clients through significant life events. Role overview The Finance Manager will take ownership of day-to-day accounting, transactional finance, and compliance. A hands-on approach is essential, with responsibility for maintaining accurate records, managing reporting cycles, and supporting the company’s continued growth. Octopus Legacy encourages professional development and supports those pursuing relevant finance qualifications. Main responsibilities Prepare monthly management accounts, including profit and loss, balance sheet, and cash flow statements. Lead month-end close activities such as reconciliations and maintaining financial controls. Monitor departmental budgets and expenses, highlight variances, and support cost management. Collaborate with external accountants, auditors, and vendors to ensure compliance and timely reporting. Improve financial systems and processes, focusing on automation as the company scales. Conduct ad-hoc financial analysis to inform commercial and operational decisions. Oversee finance-related onboarding and offboarding, including payroll and system access management. Location This role is based in London.

About the RoleJoin our dynamic Collection Engineering team as a Senior Fullstack Engineer, where you will play a pivotal role in enhancing Elliptic's efforts to combat crypto crime. You will be instrumental in developing a robust platform that empowers our intelligence organization to efficiently gather and analyze critical information, making the world safer.Your team’s mission is to amplify Elliptic’s intelligence collection capabilities by processing data from diverse sources, including external feeds, internal automation, and client submissions. This intel needs to be systematically classified, stored, and reviewed before being integrated into our proprietary graph database.Collaborate with a talented group of engineers and data scientists to create innovative tools, streamline processes, and eliminate obstacles in our intelligence pipelines.Key ResponsibilitiesDesign and implement software solutions that enhance our intelligence collection and analysis capabilities, including services on Kubernetes and browser extensions.Develop applications to analyze cryptocurrency behavior and trends across both the clear and dark web.Establish observability mechanisms to identify issues within your environments and execute necessary business processes for resolution.Mentor and coach fellow engineers to foster growth and implement best practices within the team.Actively contribute to defining and refining the engineering strategy for your team.Ideal Candidate ProfileDemonstrates a strong passion for cryptocurrencies and blockchains from both technical and economic perspectives.Possesses excellent coding skills in Typescript with a proven track record of delivering effective solutions.Has successfully integrated various systems to improve operational efficiency.Enjoys collaborating within a tight-knit team to tackle impactful challenges, contributing to a safer crypto ecosystem.Promotes a collaborative culture characterized by open communication, especially when addressing issues or concerns.Able to construct well-reasoned, data-driven arguments to influence key stakeholders effectively.

Last Energy, a pioneering force in the energy sector, is on the lookout for a dedicated Commercial Associate with a robust background in the power or energy industry. This pivotal role will focus on advancing capital formation, enhancing investor relations, and spearheading project-specific financial initiatives. You will be instrumental in supporting our strategic financing objectives and will gradually take charge of comprehensive commercial opportunities. The ideal candidate will possess exceptional analytical and financial acumen, coupled with a talent for fostering enduring relationships with investors and partners.

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