Backend Engineer - Join Our Innovative Team

Are you ready to take your career to the next level? Join Adaptive ML as a Backend Engineer and be part of a cutting-edge team that is transforming the landscape of machine learning. In this role, you will design, develop, and maintain scalable backend solutions that drive our innovative applications.

About the Role airapps is looking for a backend engineer to help build and maintain the systems behind our applications. This position is based in Paris and focuses on developing backend solutions that scale and perform reliably. What You Will Do Design, implement, and maintain backend systems for airapps products Work closely with teammates to solve technical challenges Contribute to a collaborative team environment Who We’re Looking For Experience building backend systems Comfort working with others to solve problems Interest in developing efficient and scalable solutions This is a full-time role in Paris. If building reliable backend infrastructure with a team sounds appealing, airapps would like to connect.

About UsAt Trainline, we are passionate advocates for sustainable travel, dedicated to shaping a greener future. Our platform empowers millions of travelers to easily discover and book the most cost-effective tickets across various carriers, fares, and travel options via our highly-rated mobile app, website, and B2B partner channels.Embark on Great Journeys with Trainline As Europe's leading rail app, boasting over 125 million monthly visits and £5.9 billion in annual ticket sales, we partner with over 270 rail and coach companies across more than 40 countries. Our aim is to make travel simple, seamless, eco-friendly, and affordable for everyone.Currently a FTSE 250 company, we are fueled by a diverse team of over 1,000 individuals from 50+ nationalities, operating in cities like London, Paris, Barcelona, Milan, Edinburgh, and Madrid. With a strong focus on growth within the UK and Europe, now is the ideal time to join us on this high-speed journey.Meet the Backend Teams at Trainline Our Backend teams are the backbone of Trainline's exceptional product offering. We develop the journey search capabilities that millions of customers rely on daily, create an eCommerce platform for a secure and smooth experience, and connect with over 270 transportation operators across 45 countries worldwide. Each team specializes in various domains, including journey search, fare calculations, bookings, fulfillment, payments, refunds, carrier integrations, real-time timetable data, journey disruptions, and more.Your Role as a Mid-Level .NET Engineer at Trainline Implement new functionalities or features utilizing the most suitable tools and techniques.Prioritize quality in every aspect of your work and that of your team.Continuously enhance the codebase.Keep the customer as the top priority.Proactively identify and eliminate blockers, inefficiencies, and waste.Contribute significantly to technical decision-making.Serve as a coach and mentor for your team members.Take full ownership of the development lifecycle from coding to production, including deployment and monitoring.

At Theodo HealthTech, we are continually on the lookout for exceptional talent to join our dynamic teams. If you don't find the perfect position among our current job listings, don't hesitate to reach out. We firmly believe that every unique skill set can significantly contribute to our success!

About UsAt Yubo, we are revolutionizing the way individuals connect online through our innovative Social Discovery app. By removing likes and follows, we empower our users to form authentic relationships and express their true selves.We have pioneered a fresh approach for Generation Z to engage socially in the digital realm, currently serving millions of active users. Our mission is to continuously redefine how social connections are formed now and in the future.Our team is diverse, multicultural, and passionately dedicated to our vision. As a leading platform for online socialization, we prioritize creating a safe digital environment for our community. Safety is ingrained in our values, and we proactively work on user protection, support, and education, collaborating with the tech industry and NGOs to establish best-in-class child protection standards.Join us on this exciting journey and play a vital role in shaping the future of social interactions!Role OverviewAs we expand our Tech organization for 2026, Yubo is launching a new Innovate squad dedicated to daring product initiatives and high-stakes projects.This squad aims to take bold risks, experiment with ambitious features, and validate ideas through ongoing testing.We are seeking a Senior Backend Engineer to become a key member of our Backend Experience team, reporting directly to Armand, our Engineering Manager.You will work within a multi-disciplinary squad (including Product, Mobile, Design, and Data) alongside a Senior Backend Engineer who shares leadership responsibilities.Your mission? Design, implement, and manage high-risk backend experiments that test groundbreaking product ideas while ensuring our systems remain resilient, scalable, and cost-effective throughout rapid iteration cycles.This position is not about maintenance; it's focused on building, testing, rolling back, iterating, and learning swiftly.

At Outsight, we celebrate the spirit of initiative and welcome talented individuals who wish to join our dynamic team. If you are passionate about our mission and believe your skills can contribute to our goals, we encourage you to submit a spontaneous application.To apply, please upload your resume. Our dedicated recruitment team will carefully review your submission and will reach out if a suitable opportunity arises. Thank you for considering Outsight as your future employer. We look forward to connecting with you!

As a Solutions Engineer at Adyen, you will play a pivotal role in shaping the future of payments. You will collaborate closely with our sales and product teams to deliver enhanced solutions that cater to the diverse needs of our clients. Your expertise will help us optimize our payment processing capabilities, ensuring a seamless experience for our customers.In this dynamic position, you will be responsible for understanding client requirements, providing technical support, and implementing solutions that drive success. You will have the opportunity to work with cutting-edge technology and be part of a global team that values innovation and collaboration.

At Theodo Apps, we are always on the lookout for exceptional talent to join our dynamic teams. If you don't see your ideal position among our current job listings, don't hesitate to reach out! We firmly believe that every unique talent has the potential to contribute to our success!

Join Our Team with a Spontaneous Application!Are you passionate about innovation and eager to contribute to a dynamic team? If you don’t find an open position that aligns with your skills but are excited about the prospect of working with us, we encourage you to submit a spontaneous application using the form below. We are always on the lookout for talented individuals who can help drive our mission forward.

Note: This position is based in Paris, France. Relocation and visa support are available if necessary.Achieve the Best Work of Your CareerTrade Republic stands as Europe's largest savings platform, actively engaging in 18 countries and serving over 10 million customers who trust us with more than €150 billion in assets. Our ambition goes beyond that.Our mission is to empower individuals to build wealth through easy, safe, and free access to financial systems. Join us to advance your career while collaborating with exceptional talent and cutting-edge technology, creating a positive impact for millions.Your ResponsibilitiesDevelop and test services and products utilizing modern tools from the JVM ecosystem, including Kotlin, Spring, Vert.x, Hibernate, or jOOQ.Design cloud services with a focus on high availability, low latency, and scalability (primarily on AWS).Implement automated software delivery through GitHub Actions, container-based CI/CD pipelines, and Kubernetes orchestration.Ideal Candidate ProfileA minimum of 5 years of experience in software engineering, preferably within the JVM ecosystem. We welcome candidates from mid to staff level, so whether you are looking to take on more ownership or have extensive experience leading complex systems, we encourage you to apply.Proven experience in developing and deploying scalable features within a service-oriented architecture.A strong dedication to delivering reliable and maintainable software through an iterative development approach and continuous delivery.Experience in building platform services that serve as a foundation for product development (prior experience in platform-focused teams is advantageous).Comfortable working in a flexible hybrid environment, with 2-3 days a week in the office.Why You Should Apply NowOur culture celebrates ownership, excellence, and high energy. We prioritize outcomes and accountability as we strive to tackle one of Europe's significant challenges: closing the pension gap and democratizing wealth. If you resonate with this mission, we want to hear from you!

Location Alert: This position is based in Paris, France, and we offer relocation support if needed (for candidates located within the EU).TAKE YOUR CAREER TO NEW HEIGHTSAt Trade Republic, Europe’s leading savings platform, we empower over 10 million customers across 18 countries, managing assets exceeding 150 billion Euros. Join us in our mission to revolutionize access to financial systems, enabling everyone to build wealth.As part of our team, you will collaborate with talented professionals and cutting-edge technology to create a positive impact for millions.YOUR ROLEContribute your expertise to the iOS guild, ensuring technical excellence.Mentor fellow engineers and receive coaching to foster your professional growth.Take ownership of product development, collaborating across roles to guarantee quality and timely delivery.Thrive in a dynamic, goal-oriented agile environment.WHAT WE SEEK5+ years of experience in mobile engineering.Proficiency in Swift, programmatic UI design, and foundational knowledge of reactive programming.A passion for exceptional user experience (UX) and user interface (UI), with a desire to work closely with our design team.A commitment to quality, with an understanding of best practices in coding and product development.TECHNOLOGY STACK100% SwiftSwiftUI and UIKitReactive data management using Combine, ReactiveSwift, and WebSocketsMVVM-C architectureDependency InjectionWHY JOIN US?Our culture champions ownership, excellence, and energetic collaboration. We're dedicated to achieving significant outcomes, tackling one of Europe’s major challenges: closing the pension gap and democratizing wealth. If you’re excited about making a difference, we want to hear from you!

About PreludePrelude is revolutionizing the way businesses onboard and authenticate users in a landscape where trust, speed, and conversion are paramount.Our solutions enable organizations to verify users with minimal friction, enhanced security, and cost-effectiveness, transforming authentication from a mere expense into a powerful growth catalyst. Our flagship product offers the most competitive price-to-conversion ratio for OTP codes, dynamically choosing the most efficient delivery method in real-time, from optimized SMS routing to popular messaging apps such as WhatsApp.Founded in 2022 and backed by premier venture capital firms, Prelude has swiftly established a solid product-market fit and robust financial standing, catering to rapidly growing companies across Europe while also penetrating the US market. Authentication is just the beginning.With a bold roadmap and an array of market-defining products in the pipeline, we are crafting a scalable platform for trust, empowering businesses to onboard users effortlessly, combat fraud intelligently, and expand globally with assurance.About the TeamOur founders, previous members of the Zenly team, encountered firsthand the challenges of existing authentication solutions. While developing products used by millions, we recognized the escalating costs, unreliability, and vulnerability to spam and fraud in SMS authentication, which ultimately led to the inception of Prelude.Today, we are a dedicated team of 40 and counting, based in Paris, creating products that enable secure and efficient user onboarding for businesses across Europe and the US. We believe that small, highly skilled teams can outperform larger, disjointed organizations, and we are committed to focusing on impact, quality, and speed.We maintain a flat organizational structure and prioritize in-person collaboration, which accelerates the flow of ideas, grounds decision-making, and ensures teams take full ownership of their creations.Our core values guide our daily operations:CareWe deeply care about our customers, our teammates, and the quality of our work.

Matera is on the lookout for a talented Generative AI Engineer to bolster our GenAI team, focusing on the creation of cutting-edge generative AI applications. In this role, you will enhance our internal operations and contribute to the improvement of our product offerings.As part of our data team of six, you will collaborate closely with product development and operations teams to achieve our goals.Your key responsibilities will include developing large language model (LLM) agents, integrating them into our internal tools, and continuously optimizing their performance.Key Responsibilities:Develop proof of concepts (POCs) to explore the potential of applications.Measure performance metrics and optimize solutions.Build APIs and testing interfaces for application deployment.Stay updated on technological advancements.Examples of Projects:Automated systems for addressing customer inquiries (chatbots, email responses, voice agents).Internal tools that enable our customer support team to access vital information swiftly.Document processing (contracts, quotes, etc.) to automate repetitive tasks.Our Technology Stack:Python, FastAPILangchain, LanggraphLangfuseGemini, Mistral, OpenAI

Are you passionate about data and technology? Join Magellan Partners as a Data Engineer and be part of our dynamic team in Paris! In this role, you will work on designing, building, and maintaining scalable data pipelines, transforming raw data into actionable insights to drive business decisions.

airapps is hiring a Backend DevOps Engineer in Paris. This position centers on building and maintaining systems that keep backend services running smoothly and reliably. Role overview The Backend DevOps Engineer will design and implement solutions to help backend services scale and remain dependable. Collaboration with both development and operations teams is key, with a focus on improving workflows and boosting system performance. What you will do Create and maintain scalable infrastructure for backend services Work alongside developers and operations staff to streamline processes Identify opportunities to enhance system reliability and efficiency Location This role is based in Paris.

About KonvuAt Konvu, we are dedicated to revolutionizing the security landscape, making it so seamless that it becomes invisible. Our mission is to redefine vulnerability management in an increasingly autonomous world of AI.As artificial intelligence progresses to autonomously generate, test, and deploy code, traditional security measures struggle to keep pace. That's where Konvu's AI agents come into play. They analyze security concerns with the same expertise as seasoned engineers, expertly filtering out noise, verifying potential exploits with concrete evidence, and enabling teams to concentrate on what truly matters.Our agents integrate effortlessly into existing security tools and workflows, eliminating the need for disruptive changes. We empower teams with reliable, evidence-based insights, significantly reducing false positives and highlighting actionable vulnerabilities with confidence.Founded by pioneers from Sqreen (YC W18, acquired by Datadog), we leverage our deep technical expertise to create tools that developers and security teams find indispensable.Having secured $5M in Seed funding, we are supported by prominent venture capital firms in Europe and the US, along with industry leaders from Datadog, GitHub, Docker, Cloudflare, Sumo Logic, and Vanta.

Are you a passionate Fullstack Engineer looking to make an impact? Join Doctrine as a Senior Fullstack Engineer in our dynamic Squad Scribe, where you will lead innovative projects and collaborate with a talented team. You will work on designing, developing, and implementing user-friendly applications that enhance our client's experience.

Join Fabulous Co. as a Senior Backend Engineer specializing in NodeJS and contribute to our rapid growth in the health and wellness sector. In this startup-like environment, you’ll collaborate closely with our experienced CTO to develop cutting-edge features such as marketing optimization engines and billing reports. If you’re passionate about leveraging technology to help people cultivate healthy habits worldwide, we invite you to be part of our dynamic engineering team.

Join the Voodoo TeamFounded in 2013, Voodoo is a leading technology company dedicated to creating captivating mobile games and applications with the goal of entertaining users across the globe. With a robust workforce of 800 talented individuals, we have achieved over 7 billion downloads and boast more than 200 million active users. Voodoo stands as the third largest mobile publisher worldwide by downloads, trailing only Google and Meta. Our impressive portfolio features popular titles such as Mob Control and Block Jam 3D, along with trending apps like BeReal and Wizz.Your RoleAs a Senior Backend Engineer, you will collaborate within a dynamic team of five engineers focused on enhancing our gaming backend platform. This role requires close interaction with various departments, including Core Gaming, Live Gaming, and Engineering & Data. You will contribute to our transition from Hyper-Casual to Hybrid, Casual, and Mid-Core games, playing a pivotal role in scaling our backend architecture to support new and existing titles.Your responsibilities will encompass designing scalable backend systems that serve millions of players daily. You'll partner with client developers and game designers throughout the entire process, from conceptualizing new features to their successful implementation and iteration.

About VibeAt Vibe.co, we are revolutionizing the way brands connect with audiences in the streaming era. We envision that streaming TV transcends traditional brand awareness; it is poised to be the next major avenue for performance marketing. Our mission is to create the infrastructure that harnesses this $100 billion potential.As a leader in Audience First Streaming TV Advertising, Vibe.co empowers marketers to leverage TV as an effective growth channel. Our comprehensive solution integrates hyper-targeted audience segmentation, AI-driven insights, real-time campaign optimization, and incrementality measurement, providing brands of all sizes the accuracy and transparency they expect from social and search advertising, applied to the TV landscape.With over 10,000 trusted brands and a reach of more than 120 million households across 500+ apps and channels, Vibe.co consistently delivers an impressive average return on ad spend of 250% and a 20% lift in sales. Achieving a $100 million revenue run rate in less than two years, we are among the fastest software companies to reach this remarkable milestone.Our investors include notable firms such as Hedosophia (early backer of Spotify, Uber, and Airbnb), Elaia, Singular, QuantumLight, and Illusian, alongside angel investors like Carolyn Everson, board member of The Walt Disney Company and Coca-Cola. Nirav Tolia, CEO of Nextdoor, is also a member of our board of directors.Founded in 2022, Vibe.co is recognized as a pioneering platform in streaming TV advertising, merging the power of performance marketing akin to Meta and Google with the fast-evolving media landscape.About the RoleAs a key member of the Performance team, you will play a vital role in managing advertiser outcomes at Vibe. Your focus will be on bidding, pacing, and enhancing the prediction stack that drives these elements. You will report directly to Clément Schiano, Engineering Manager for Performance.This position has been created to address a clear roadmap and enhance execution capabilities, as well as to mitigate knowledge concentration challenges within the team. We seek an individual who can absorb, challenge, and expand upon existing expertise, going beyond simply delivering tickets.Three compelling reasons why a talented candidate would find this role appealing: