[FREELANCE] Back-End Engineer - Addressability

👫 Join Our Innovative TeamAt Equativ, we are dedicated to creating cutting-edge advertising technologies that help our clients achieve their digital business objectives. Our extensive platform processes over 3 million requests per second, resulting in more than 250 billion daily requests, all managed by a robust infrastructure of 3,000 servers, delivering r…

Join Our Innovative Team At Equativ, we are dedicated to revolutionizing advertising technology to help our clients achieve their digital business objectives. Our platform is engineered to handle over 3 million requests per second, translating to more than 250 billion requests daily. We pride ourselves on our infrastructure, which operates on 3,000 servers with an impressive response time of under 250 milliseconds. Our innovation hub, located in Paris, Nantes, Bordeaux, Limoges, Krakow, and Berlin, is home to over 150 dedicated and dynamic engineers, all committed to solving complex technical challenges in an Agile environment.

Join ScorePlay, the leading AI media platform in sports dedicated to enhancing the connection between clubs, athletes, and fans. We collaborate with over 270 clubs, leagues, and federations, including prestigious names like Ligue 1, Premier League, NBA, NFL, Tour de France, Australian Open, UEFA, and FIBA. Our mission is to transform every significant moment, both on and off the field, into engaging content that strengthens community ties.Since our inception in 2021, our dynamic 45-member team has expanded rapidly, achieving a remarkable 3x growth year over year and an almost 100% retention rate. With over $20M raised from prominent investors, including Alexis Ohanian and elite athletes like Kevin Durant and Raphaël Varane, we are making significant strides in the sports media industry.If you have a passion for sports and thrive in a fast-paced work environment, we invite you to help us redefine how future generations experience sports. This is an exceptional opportunity to join a company poised to become the global leader in sports media. OverviewWe are seeking a talented Senior Back-end Engineer to become a pivotal member of our Video Production team, which is central to ScorePlay's innovative platform.In this role, you will take charge of the back-end services that drive our video processing and media automation systems, ensuring they are robust and efficient.This is a unique opportunity for an individual who desires autonomy and impact in their work, ready to take full responsibility for their projects while collaborating across product, video, and front-end teams. What You Will Work On:Backend DevelopmentDesign, develop, and maintain back-end services, APIs, and data pipelines using Go and related technologies.Monitor system performance and reliability to ensure scalable and maintainable solutions.Data & DatabasesDesign and optimize database schemas, queries, and indexing for efficient data storage and retrieval.

About NablaAt Nabla, we are a dynamic collective of entrepreneurs, clinicians, and engineers dedicated to reinvigorating the joy of practicing medicine.In collaboration with a community of innovative clinicians, we have leveraged cutting-edge machine learning to create Nabla: the premier AI assistant designed to restore the human connection in healthcare. By optimizing clinical documentation, Nabla empowers clinicians to prioritize what truly matters—their patients. Currently, over 85,000 clinicians from more than 130 healthcare organizations rely on Nabla to enhance their daily care delivery.We are embarking on an ambitious journey to integrate ambient listening, dictation, coding, and command functionalities into a proactive assistant that seamlessly streamlines both clinical and financial workflows.With a recent $70M Series C funding, we are expanding our team to build the next generation of clinical AI and enhance the lives of clinicians and patients worldwide.This is an exciting moment to join our mission!The Best of AI Serving HealthcareNabla’s remarkable success is a testament to three years of dedicated product development.Guided by former Meta AI Research engineers, our team has consistently envisioned how AI can transform healthcare delivery. Our Machine Learning team is at the forefront of utilizing the latest advancements to unlock AI’s full capabilities within the healthcare sector.Yann LeCun, Chief AI Scientist at Meta and Turing Award laureate, serves as an advisor for Nabla.Engineering Excellence at NablaAt Nabla, our engineering culture is agile, innovative, and deeply technical. Our teams encompass machine learning, native desktop applications, and platform infrastructure, working together to deliver AI reliably and at scale in clinical settings.Your TeamIn our organization, product development is a collaborative effort led by Engineering and Product, structured into cross-functional squads focusing on specific product areas. Each squad comprises product managers, designers, engineers of various specializations, and domain experts, functioning with high ownership. As a Senior Back-End Engineer, you will be an integral part of one of these squads, contributing from end to end to a specific product segment.What You'll DoIn your role as a Senior Back-End Engineer, you will be instrumental in scaling Nabla’s AI-powered healthcare platform. You will own key components of our back-end systems, closely collaborate with product and machine learning teams, and influence the technical direction of our projects.

Join our dynamic team at myjobcompany1 as a Back End PHP Developer. You will work on exciting projects that contribute to our innovative software solutions. Your primary focus will be on designing and implementing server-side logic, ensuring high performance and responsiveness to requests from the front end.

Join Voodoo as a Senior Back-end Engineer to lead the development of Wizz, a dynamic social app for teens. Utilize your technical expertise to enhance our backend architecture, optimize scalability, and ensure performance for millions of users. Collaborate with cross-functional teams to shape the product vision and contribute to decision-making processes, making a tangible impact in the world of mobile applications.

Join our dynamic team as a Back-End Developer specializing in NodeJS. You will be responsible for developing and maintaining high-performance server-side applications. Collaborate with our front-end developers to integrate user-facing elements with server-side logic. Your role will also involve optimizing applications for maximum speed and scalability.

At Flowdesk, we are on a mission to revolutionize financial services for digital assets, establishing a global institution meticulously designed for market integrity and efficiency.In a fast-paced and continuously transforming market, we employ a disciplined, first-principles methodology that permeates every aspect of our operations. This philosophy is integral to our core services, which include institutional liquidity provision, trading solutions, OTC execution, and extensive treasury management offerings. Our dedication to clarity and efficiency allows us to craft resilient and scalable systems across our diverse business verticals.We are looking for passionate individuals who resonate with our systematic approach. Joining Flowdesk means contributing significantly to the creation of a more transparent and efficient financial market infrastructure.As a Senior Back-End Engineer at Flowdesk, you will play a pivotal role in designing and developing the foundational services that drive our global trading platform. Reporting directly to Flowdesk’s Lead of Backend Engineering and collaborating closely with the Infrastructure, Trading, and Data teams, your contributions will be vital to the scalability, performance, and reliability of our backend systems.Your collaborative mission with the backend team will encompass:Crafting, developing, and sustaining microservices primarily in Rust, with additional services and tools developed in TypeScript.Engaging in system architecture and design discussions that shape the future of our backend services and trading platform.Creating scalable and resilient backend systems to support OTC and API trading workflows.Building and optimizing high-performance trading services with an emphasis on low latency, high throughput, and fault tolerance.Designing and maintaining REST and WebSocket APIs, ensuring appropriate versioning, comprehensive documentation, and seamless integration for both internal and external clients.Writing clean, maintainable, and testable code in adherence to industry best practices, code review standards, and internal guidelines.Monitoring, diagnosing, and resolving production issues, including performance bottlenecks and service outages, in close cooperation with SRE/Infra teams.Deploying, scaling, and monitoring microservices in cloud and containerized environments, utilizing tools such as Kubernetes and modern CI/CD pipelines.

Join our dynamic team at Sunrise United States Inc. as a Python Back-End Developer. We are seeking a talented developer who is passionate about crafting efficient, scalable code and creating innovative back-end solutions. If you thrive in a collaborative environment and have a strong understanding of Python and back-end technologies, this is the perfect opportunity for you!

Join our Digital Transformation team at altersolutions, where you will collaborate with a group of software development experts dedicated to supporting our clients.You will be assigned to a leading player in the Banking and Market Risk sector, working alongside a team of skilled developers.Your responsibilities will include:Enhancing the web application by adding new validation criteria for risk analysis and improving its usability.Modifying and evolving integration workflows.Developing a web service for the automatic update of all deals referenced in the application.Creating a Windows service to manage snapshots of financial indicator versions.Analyzing and resolving anomalies.Acting as a release manager.Facilitating production deployment.

Join our innovative team at nexton as a Back End Developer specializing in Scala. In this role, you will play a crucial part in designing and implementing robust backend systems that support our applications in the Telco, Media, and Transport sectors. You will collaborate with cross-functional teams to deliver scalable solutions and enhance system performance.

Octopus Energy is a bold initiative aimed at making energy greener, more affordable, and accessible to everyone by establishing the first truly digital energy provider. Although the project originated in the United Kingdom, it has expanded to France since 2022! By combining cutting-edge technology with talented individuals committed to our customers and the transition to renewable energy, we continue to bring this vision to life. In just three years, we've become the fifth largest energy supplier in France! Our mission? To provide cheaper and greener energy to all French citizens and offer practical solutions to accelerate the ecological transition. Currently, we are developing the next generation of products to expedite the shift to green energy. Whether it’s facilitating the transition to solar energy, electric vehicles, implementing smart pricing, or enhancing large-scale renewable energy production, we tackle some of the most complex challenges in the energy sector! All while being faster, more creative, and with one obsession in mind: customer satisfaction. As a member of the Octopus Tech team, you will enjoy significant autonomy, a wide variety of projects to work on, and the opportunity to shape products that make a real difference in people's everyday lives—reducing their bills, enabling a more sustainable lifestyle, and providing experiences they will truly appreciate. You will closely collaborate with Octopus teams in France, including marketing, operations, and data, as well as technical teams from other countries in the group . Most importantly, you will quickly see the impact of your work in the real world and with our customers. If this resonates with you, we would love to discuss it further. Within the OE Tech France team, you won’t just be coding: you will build the technological engine that makes green energy simple and intuitive for all French citizens. You will join a small, agile team structured for innovation, where seniority and collaboration are key:- A strong core: You will work daily with 1 Product Manager, 4 Frontend Developers, and 3 Backend Developers. The Backend team is primarily composed of senior profiles, allowing you to thrive in a demanding technical environment.- Synergy with Data : Our data-driven approach ensures that your contributions directly enhance our service quality and customer experience.

Located in the vibrant heart of Paris, Winamax is revolutionizing the online gaming industry. As a leading platform for poker and sports betting in France, we boast a community of over 350,000 players and 600,000 monthly bettors. Our services extend to Spain, Germany, and soon to Italy and Portugal. We pride ourselves on delivering an exceptional experience that is technical, creative, and of high quality. Innovation, unity, and belonging are the core values that shape our unique and multicultural corporate culture.Are you ready to shape the future of gaming?Technically, Winamax offers:• A powerful and innovative gaming engine: dynamic game offer adjustments, highly configurable poker games, and fraud detection.• A distributed and scalable architecture designed for real-time processing of platform flows.• A modular platform adhering to high availability and data security constraints, capable of handling heavy traffic.ABOUT THE ROLEAs a member of the Poker team, you will play a key role in the design, implementation, and oversight of the microservices powering our poker platform.ROLE DESCRIPTION• Design of the platform architecture.• Development of highly available and scalable microservices.• Development of APIs and data models.• Writing unit and end-to-end tests, and running scenarios in real-world conditions.• Participating in team code reviews.• Deployment of applications on AWS.• Monitoring and optimization of the poker platform.• Documenting the architecture and poker services.• Collaborating with Front-End, Data, Infrastructure, Security teams, and project managers.Examples of projects include:• Creating a poker gateway with authentication, rate limiting, routing, and pub/sub (10K+ messages/second).• Implementing a registration microservice (1,000 registrations/second).PROFILE SOUGHTThe ideal candidate will possess the following qualities and skills:• Significant experience in developing Back-End services on high-traffic platforms (10K+ requests/second).• Proven experience with load balancing, high availability, scaling, caching, database, and storage challenges.• Proficiency in architectural best practices and microservices development.

Your Responsibilities :As a Java JEE Developer / Software Engineer (H/F), you will collaborate with an agile team to drive back-end or full-stack development for one of our esteemed clients, focusing on:Analyzing architecture to ensure improvements meet expectations.Developing analytical tools for delivered components.Creating new features on a new platform compatible with current architecture.Automating testing procedures.Additionally, you will be involved in:User demonstrations.Integration testing.Production delivery (coordinating with infrastructure and security teams).Web and server development (NGINX, Apache, Tomcat, ...).Production and operational deployment procedures.Continuous integration (Jenkins, GitLab, Bitbucket, ...).Continuous deployment (Ansible, AWX, Octopus, GitLab, ...).Creating and participating in test cases.

Located in the bustling heart of Paris, Winamax is revolutionizing the online gaming industry. As the leading poker and sports betting platform in France, we boast a community of 350,000 players and 600,000 bettors each month. Our presence extends to Spain, Germany, and soon, Italy and Portugal. We are committed to providing our players with an extraordinary experience that is technical, creative, and high-quality. Innovation, unity, and belonging are the core values that shape our unique and multicultural corporate culture.Are you ready to shape the future of gaming?From a technical perspective, Winamax offers:• A powerful and innovative gaming engine: dynamic game offering adaptation, highly configurable poker games, and fraud detection.• A distributed and scalable architecture designed for real-time processing of platform flows.• A modular platform that meets high availability and data security requirements, capable of managing heavy traffic.ABOUT THE POSITIONTo support Winamax’s growth and the increasing number of design projects, we are looking for a Fullstack Developer with a strong Back-End focus (Node, React).As part of the Operator team, you will design and develop applications for managing our online gaming operations, specifically within the payment vertical.Your responsibilities will include:• Integrating new partners and payment methods.• Maintaining and evolving existing code to ensure compliance with regulations (including PCI DSS standards).• Harmonizing and optimizing historical code for improved maintainability and performance.• Developing internal tools for the fraud prevention and customer support teams.Our preferred environment, ideally yours as well:• NodeJS, React, PHP• Object-oriented programming / TDD / DDD• MySQL, Relational model, stored procedures, triggers, integrity constraints

nexton is hiring a Back End Developer to join the team in Paris. This role centers on building and maintaining server-side services using Java, NodeJS, Kotlin, and AWS. What you will do Design, develop, and maintain back-end services for nexton applications Collaborate with colleagues across teams to deliver software solutions Support and enhance nexton's products through project contributions Key technologies Java NodeJS Kotlin AWS Location This position is based in Paris.

Join our dynamic team at myjobcompany1 as a Senior Front-End Engineer (H/F)! In this role, you will play a crucial part in developing cutting-edge web applications that provide an outstanding user experience. You will collaborate closely with designers and backend developers to create seamless and responsive user interfaces. We are looking for innovative thinkers who are passionate about technology and eager to contribute to exciting projects.

Join Back Market as a Backend Engineer Apprentice and embark on a journey to innovate and enhance the circular economy through technology. As a part of our dynamic team, you will gain hands-on experience in backend development, contributing to our mission of creating a more sustainable world.

Blockchain.com is at the forefront of revolutionizing the financial landscape through cryptocurrency. As the leading and fastest-growing global crypto company, we empower millions of individuals around the globe to access cryptocurrency securely. Since our inception in 2011, we have gained the trust of over 90 million wallet holders and more than 40 million verified users, facilitating over $1 trillion in crypto transactions.We are on the hunt for a talented Front-End Engineer with a passion for crypto and Web3 technologies to join our dynamic engineering team. In this role, you will work on developing innovative Blockchain applications that are among the most popular in the crypto ecosystem. Your contributions will shape user interfaces that power future wallets, block explorers, financial and market data products, along with cutting-edge visualizations.Our engineering teams engage in all phases of the product life cycle, encompassing idea generation, design, prototyping, planning, execution, and deployment.

About LedgerAt Ledger, we are a team of innovators dedicated to redefining digital ownership. Our mission is to empower individuals and enterprises alike through secure management of their assets, ensuring that technology is accessible for everyone. We envision a future where users, creators, and businesses have full control over their value. Driven by curiosity and a commitment to continuous improvement, we seek to inspire global change and support our team in challenging the status quo to develop cutting-edge solutions. Join us in making self-custody not only attainable but also a fundamental right.With our headquarters in Paris and a presence in several global cities including London, Geneva, and Singapore, Ledger stands as the leading platform for digital assets and Web3. We proudly secure over 20% of the world's crypto assets through our innovative Ledger devices, with more than 7.5 million units sold across 200 countries.The Team:Ledger Wallet serves as our flagship application, built on an Open Source monorepo utilizing React, Electron (Desktop), and React Native (Mobile). It supports various blockchains and integrates multiple decentralized applications (DApps).As part of the Platform Team, you will be integral to laying the groundwork for Ledger Wallet. Our focus extends beyond feature development; we construct the infrastructure that empowers other teams to deliver enhancements swiftly and securely.We are in search of a Senior Engineer to take ownership of our tech stack, refine our monorepo architecture, and facilitate the transition to micro-frontends. Your primary audience will be fellow developers, as you prioritize tooling, build speed, and overall Developer Experience (DX).