
Zefir · Paris or remote
WHO WE ARE Zefir is building an AI autopilot for home sales in Europe, starting in France: an AI agent runs the entire sale and purchase journey end-to-end, or...
Zefir is building an AI autopilot for home sales in Europe, starting in France: an AI agent runs the entire sale and purchase
journey end-to-end, orchestrating local brokers, portals, buyers, and documents.
Backed by over $55 million from top-tier investors like Sequoia Capital, we're committed to accelerating life changes for millions
of current and future European homeowners.
At Zefir, our Engineering Team is the driving force behind our mission to accelerate life changes. Growing rapidly from 9 to 30+
engineers, we don’t just write code—we solve meaningful problems for our customers.
From ideation to launch and beyond, engineers at Zefir take full ownership of their work, ensuring that every feature delivers the
expected impact. We leverage LLM-based development workflows and shared best practices to automate repetitive tasks, allowing us
to keep our codebase lean, scalable, and built for speed.
deliver key objectives.
Pinecone and Langchain.
THE FOLLOWING IS FOR PERMANENT EMPLOYEES ONLY. FOR OTHER CONTRACTS (INTERNS, APPRENTICES, FIXED-TERM..), PLEASE, CHECK WITH YOUR
🏔️ Steep Mountains Are Steep: Setting ambitious goals and working hard to achieve them.
🌊 Ride Reality: Actively seeking challenges and thriving by adapting flexibly to changes.
🏀 Play for the Front of the Jersey: Prioritizing team success over individual recognition.
We welcome applications from anyone, regardless of background, gender, sexual orientation, religion, age, or experience. Our team
values authenticity and diverse perspectives.
For all roles, our interview process emphasizes hands-on exercises, case studies, or discussions about specific examples of your
previous work. We ensure objectives and expectations are clearly communicated at every step.
Visa’s Technology Organization is a community of problem solvers and innovators reshaping the future of commerce. We operate the world’s most sophisticated processing networks capable of handling more than 65k secure transactions a second across 80M merchants, 15k Financial Institutions, and billions of everyday people. While working with us you’ll get to work on complex distributed systems and solve massive scale problems centered on new payment flows, business and data solutions, cyber security, and B2C platforms. The Opportunity: We are looking for Versatile, curious, and energetic Software Engineers who embrace solving complex challenges on a global scale. As a Visa Software Engineer, you will be an integral part of a multi-functional development team inventing, designing, building, and testing software products that reach a truly global customer base. While building components of powerful payment technology, you will get to see your efforts shaping the digital future of monetary transactions. The Work itself: Design code and systems that touch 40% of the world population while influencing Visa’s internal standards for scalability, security, and reusability Collaborate multi-functionally to create design artifacts and develop best-in-class software solutions for multiple Visa technical offerings Actively contribute to product quality improvements, valuable service technology, and new business flows in diverse agile squads Develop robust and scalable products intended for a myriad of customers including end-user merchants, b2b, and business to government solutions. Leverage innovative technologies to build the next generation of Payment Services, Transaction Platforms, Real-Time Payments, and Buy Now Pay Later Technology Opportunities to make a difference on a global or local scale through mentorship and continued learning opportunities Essential Functions: Demonstrates relevant technical working knowledge to understand requirements. Identifies and contributes to the development and solution strategies to team members that improve the design and functionality of interface features across one or more project features, under minimal guidance. Applies standard processes on the use of programming languages (e.g. HTML, C++, Java) to write code that fulfills website modification requests and technical requirements. Collaborates with others to support the piloting of new technology capabilities and features that enhance the user website experience across e-commerce products. Analyzes bugs for simple issues and applies debugging tools to verify assumptions. The Skills You Bring: Energy and Experience: A growth mindset that is curious and passionate about technologies and enjoys challenging projects on a global scale Challenge the Status Quo: Comfort in pushing the boundaries, “hacking” beyond traditional solutions Language Expertise: Expertise in one or more general development languages (e.g., Java, C#, C++) Builder: Experience building and deploying modern services and web applications with quality and scalability Learner: Constant drive to learn new technologies such as Angular, React, Kubernetes, Docker, etc. Partnership: Experience collaborating with Product, Test, Dev-ops, and Agile/Scrum teams Qualifications: Basic Qualifications Bachelor's degree in Math, Science, Engineering, or Computer Science, Information Systems or related field AND minimum five (5) years of experience in a directly related field. OR Master's degree in Math, Science, Engineering, or Computer Science, Information Systems or related field AND minimum three (3) years of experience in a directly related field. OR Minimum eight (8) years of directly related experience. Preferred Qualifications Programming Languages: Knowledge of and ability to develop front-end code (e.g. HTML, CSS, and JavaScript) in support of package and product development. This includes the extension of capabilities of packages and products. Web Browser Optimization: The ability to select the "best available" values of some objective function to improve the functional effectiveness of web browsers. User Interface Design: Knowledge of user interface design, which is the interaction where users and computers interact. This includes an understanding of how to provide an optimal industrial design experience through User Interface (UI) Design. API Generation: The ability to develop and apply Application Program Interfaces (APIs), a set of routines, protocols, and tools for building software applications that specify how software components should interact and are used when programming graphical user
About the role We are looking for an experienced Software Engineer with deep expertise in building scalable backend systems, distributed microservices, and modern cloud-based infrastructure as well as a demonstrated interest in or experience with GenAI and LLM technologies. This role is ideal for someone who thrives on solving complex architectural challenges and has a strong track record of building and deploying reliable, high-performance software systems at scale. You will be instrumental in designing core systems, APIs, and data flows, while contributing to the evolution of our infrastructure. You’ll collaborate across cross-functional teams to deliver robust solutions, audiovisual data processing, and modern AI/LLM systems and workflows. Key Responsibilities and Qualifications Design, develop, and maintain scalable backend services using one or more of: TypeScript, Node.js, PHP, and Python Design and build powerful REST APIs. Design and and take full cycle ownership of distributed microservices Familiarity with Generative AI technologies and Large Language Models Design, optimize, and manage relational and NoSQL databases including MySQL, DynamoDB, Redis, and Apache Druid Define and implement infrastructure as code using Terraform on AWS Build and maintain robust CI/CD pipelines 5+ years of professional software development experience Bachelor’s degree in Computer Science, Artificial Intelligence, Machine Learning or similar field. Proven ability to work in fast-paced, cross-functional environments Nice to have Solid foundation in machine learning, AI, and statistical methods Hands-on experience deploying and managing both cloud-native and self-hosted services Experience with VOIP telephony stacks including Asterisk and Kamailio Our ways of working Each team has clear responsibilities and goals and the freedom to collaborate on the optimal design for the products and solutions we build. We want to hear your opinion! We have an agile approach to processes and teamwork and we constantly evaluate and adapt. Our Product and UX teams are closely integrated with development. We use modern frameworks and the best tools available. We work flexibly and have fun at work. Delivering customer value is as important as the wellbeing of our friends and colleagues. We value personal growth and encourage learning, and embrace every opportunity to share knowledge in the team. Where you’ll be and how you’ll work We have three offices: London, Uppsala and Paris. This role is based in the Uppsala office. We work business hours, but we understand that life sometimes gets in the way. Kaisa Culture What makes Kaisa stand out? Our values, guiding us every day: Innovate with Agility - We move fast, think creatively, and adapt seamlessly. Win Together - Success is a team effort, and we celebrate it as one. Own It - Accountability drives progress, and we take pride in our work. Champion Sustainability and Diversity - We foster inclusivity and make responsible choices. Spread the Vibe - A positive atmosphere fuels great ideas and connections.
About Kambi Kambi Group plc is a leading B2B provider of premium sports betting services to licensed gaming operators. Our services provide an end-to-end solution for operators wanting to launch a standalone Sportsbook or bolster their existing offering with an innovative sports betting product. From front-end user interface to customer intelligence, risk management and odds compiling, all built on our in-house developed software, we strive to deliver the ultimate service and solution to our partners. Our vision is to create the world’s leading sports betting experiences, together with our partners. About the Role We’re looking for a Senior Software Engineer to join Kambi. This is not a standard backend role. You will work on business-critical systems where: Performance matters. Reliability is essential. Correctness is critical. We’re looking for someone who takes ownership, makes sound technical decisions, and contributes effectively in a complex, high-impact environment. What You’ll Do Design, build, and maintain high-throughput backend services in Java Work with low-latency, distributed systems Solve real production challenges related to performance, failures, and scaling Take ownership of systems and features end-to-end Collaborate closely with engineers, product, and stakeholders Contribute to architectural decisions and technical direction Continuously improve system reliability, observability, and maintainability What You Bring Strong Java & Backend Expertise Solid understanding of: Concurrency and multithreading JVM behavior (memory, garbage collection, performance) Core Java fundamentals Experience building backend services using frameworks such as Spring Boot Experience Working with Production Systems Hands-on experience debugging and resolving issues in live systems Familiarity with observability practices (logging, metrics, tracing) Experience identifying and addressing performance bottlenecks Understanding how systems behave under real-world load Distributed Systems & System Design Experience working with microservices and/or event-driven architectures Understanding of: Scalability and fault tolerance Backpressure and system resilience Trade-offs such as consistency vs availability Experience with messaging systems (e.g. Kafka) is highly valued Ownership & Engineering Judgment Take responsibility beyond individual tasks and drive work forward Operate effectively in environments with some ambiguity Proactively identify issues and drive improvements Make sound technical decisions and clearly communicate trade-offs Balance simplicity, performance, and long-term maintainability Understand the operational and maintenance impact of technical choices This Role May Not Be the Right Fit If Your experience is primarily limited to simple CRUD-based applications You have limited exposure to debugging or operating production systems You are most comfortable working in environments where requirements are fully defined upfront and change is limited You are not comfortable taking ownership of systems end-to-end Tech Context Java (primary) Spring Boot Distributed systems and messaging (e.g. Kafka) Cloud-based infrastructure Containerized environments Application Please share your CV in English. Along with your CV, to help us better understand your experience, kindly include a brief description of a complex production issue you personally debugged, how you approached it, and the outcome. #wearekambi