Mid-Level Backend Engineer - Carpool Monetization

BlaBlaCar’s Carpool Supply team in Paris works on the systems at the heart of the company’s carpooling platform. As a Backend Engineer here, the work shapes how people arrange and share rides, influencing the experience for both drivers and passengers. Role overview This position centers on developing and refining backend services that support carpooling features. The team’s efforts help ensure the platform remains reliable and easy to use as it grows. What you will do Design, build, and maintain backend services for carpooling Create solutions aimed at improving the experience for drivers and passengers Work closely with engineers and product teams to deliver systems that scale and perform reliably Location This role is based in Paris, France.

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.

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.

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:

About the Role Shift Technology is looking for a Junior Backend Engineer with C# experience to join the team in Paris, France. This role focuses on building and maintaining backend systems that power the company's products. Work closely with seasoned engineers and contribute to projects that shape Shift Technology's technical direction. What You Will Do Develop and support backend components using C# Help maintain and improve existing systems Collaborate with other engineers on technical projects Location Based in Paris, France.

Join Mistral as a Backend Software Engineer and be part of a dynamic team that is shaping the future of cloud technology. In this role, you will be responsible for developing robust backend systems, ensuring seamless integration, and optimizing performance. Collaborate with cross-functional teams to deliver innovative solutions that meet our clients' needs.

Role Overview JobTeaser is hiring a Senior Backend Engineer with strong Ruby experience to join the team in Paris. This role focuses on building and maintaining scalable backend systems that support our platform. What You Will Do Design, develop, and maintain backend solutions using Ruby Work with cross-functional teams to deliver reliable features and improvements Write high-quality code that supports a strong user experience Location This position is based in Paris.

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!

Join our dynamic team as a Backend Engineer specializing in Rust at connecthum, a pioneering AI infrastructure startup dedicated to constructing the safety and control layers for expansive AI systems.About connecthum:We are an AI-native product company focusing on AI safety and infrastructure.Supported by a diverse range of international investors.Our systems manage high volumes of AI traffic across enterprise environments.We train and fine-tune our proprietary models to ensure optimal performance and reliability.A compact yet highly skilled team that delivers rapid results.Our mission is to create the evaluation and control layer for AI systems, enabling organizations to define, test, and enforce AI behavior in real-world situations.Your Contribution:Design and implement robust Rust backend services that facilitate real-time policy enforcement.Take ownership of features from conception to deployment - including API design, database schema, and monitoring.Develop high-throughput data pipelines to manage extensive AI traffic efficiently.Enhance system performance, reliability, and observability.Collaborate across the stack as needed, prioritizing problem-solving over strict boundaries.Work closely with product, research, and ML teams to drive innovation.This role is hands-on, directly influencing how AI operates in production settings.Technical Environment:Asynchronous Rust (Tokio)Utilizing modern web frameworks such as Axum and ActixPostgreSQL for large-scale applicationsImplementing caching and event streaming architecturesBuilding high-throughput distributed systemsFocus on production observability and performance tuning(In-depth technical stack details will be shared during interviews)Your Expertise:Demonstrated production experience in developing backend systems using Rust.Strong foundation in asynchronous programming and concurrency principles.Excellent system design capabilities, including scalability, failure modes, and trade-offs.Proficient with PostgreSQL and other related technologies.

Join adaptive-ml as a Backend Engineer specializing in database management and development. In this pivotal role, you will be responsible for designing, implementing, and maintaining robust backend systems that support our advanced machine learning applications. You will collaborate closely with cross-functional teams to optimize database performance, ensure data integrity, and enhance overall system functionality.

About the Role airapps is looking for a Backend QA Engineer in Paris to help keep our backend systems reliable and high quality. This role works closely with engineers and product managers to improve how we build and test software. What You Will Do Develop and maintain testing frameworks for backend applications Create automated tests to catch issues early and ensure smooth releases Collaborate with team members to refine development and QA processes Help uphold quality standards so our applications meet user needs Location This position is based in Paris.

BlaBlaCar’s Payment Squad is seeking a Backend Engineer based in Paris. This team plays a key role in building and enhancing the systems that process payments throughout the platform. The work ensures millions of users can complete transactions smoothly and reliably. Main responsibilities Design, develop, and maintain backend services for payment processing Collaborate with fellow engineers to create scalable technical solutions Contribute to making transactions more reliable and efficient for users Team collaboration This role involves close teamwork with experienced colleagues. Sharing ideas and tackling technical challenges together is a regular part of building and improving payment features at BlaBlaCar.

About VoodooEstablished in 2013, Voodoo is a pioneering technology company dedicated to crafting engaging mobile games and applications that aim to entertain audiences globally. With a dynamic team of 800 professionals, we boast an impressive milestone of 7 billion downloads and over 200 million active users, positioning Voodoo as the third largest mobile publisher worldwide, trailing only Google and Meta. Our diverse portfolio features hit games such as Mob Control and Block Jam, in addition to popular applications like BeReal and Wizz.Our TeamAt BeReal, we are committed to promoting authenticity in social media. By encouraging users to capture and share genuine moments, we build real connections and celebrate everyday life. Our international team, comprising over 60 members, engages more than 30 million monthly active users. With the backing of Voodoo, we are determined to scale BeReal into a leading social network that serves hundreds of millions worldwide.Your RoleAt BeReal, we have built our platform with a compact yet highly skilled technology team, and we intend to maintain this approach as we grow to accommodate hundreds of millions of users. Our commitment to speed allows us to deploy new features faster than any other established social network while we enhance our infrastructure. We operate in small, agile teams, granting each engineer significant autonomy to influence product decisions.Address thrilling technical challenges, given the unique nature of our product, which experiences user surges of millions within short timeframes.Play a vital role in developing a resilient architecture capable of accommodating massive scale as we attract new users and expand globally.Collaborate with product and engineering teams to innovate and implement new app features.Evaluate trade-offs and tackle technical challenges associated with critical backend components.Engage in code and design reviews to uphold our quality standards.Our Technology StackInfrastructure: GCP, Kubernetes, Pub/Sub, GitHub Actions, and ArgoCD.Backend: Go, Node.js (NestJS, Nx, TypeScript)Frontend: Swift (iOS), Kotlin (Android).Database: Spanner, PostgreSQL, Redis.Ideal Candidate ProfileYou possess over 5 years of experience in API development within distributed architectures.You have demonstrated expertise in Go and have a track record of developing high-volume API microservices.You are a self-motivated individual with excellent problem-solving skills and a strong desire to innovate.

Join the dynamic technical teams at iad Business Factory, where you will work under the guidance of an Engineering Manager. You will be part of a collaborative squad consisting of developers, Product Owners, Project Managers, Quality Assurance specialists, and designers, all focused on enhancing our Playiad application.Your role will involve developing innovative web-oriented projects as well as evolving and maintaining existing features in a continuous improvement mindset.You will be integrated into the Grow Squad within the MLM Tribe, responsible for core MLM model developments including sponsorship, onboarding, accreditation, real estate training, organizational dynamization (gamification), and genealogical evolution across various geographies. Your primary responsibilities will include:Developing based on concepts established by the technical management (Clean Architecture, TDD, DDD, BDD, etc.),Understanding the business needs of each user story (product culture),Ensuring high quality in deliverables through test-driven development,Engaging in self-directed learning and staying updated on technologies and best practices,Adopting a straightforward and pragmatic approach to development,Collaborating closely with your product family members,Ensuring the reliable operation of applications in production ("You build it, you run it"),Adhering to software craftsmanship principles and XP practices. Technical stack:Development: PHP, SymfonyDatabases: PostgreSQL, MySQLInfrastructure as Code: Terraform, AnsibleAWS: EC2/ECS, RDS/Aurora, Lambda/Step Functions, API GatewayCommunication systems: RabbitMQ, AWS SQS, SNSLinux environment, Shell scripting, Cron jobs, etc.CI/CD tools: GitHub, Docker, GitHub Actions, Jira, Confluence

About UpflowUpflow is a pioneering SaaS startup specializing in advanced cash collection technology designed to help B2B companies streamline their payment processes and get paid more efficiently.Founded in 2018, we have quickly gained the trust of hundreds of businesses across the US and EMEA, partnering with notable clients such as Lattice, ProductBoard, and Instawork. Our growth has been fueled by leading investors including YCombinator, eFounders, and prominent business angels from companies like N26, Square, Mercury, Uber, and NetSuite.Join us for an exciting opportunity to work within a rapidly evolving Fintech landscape in a diverse and international setting.To learn more about our team and culture, please visit our careers page at www.upflow.io/careersAbout the RoleAs a Senior Backend Engineer, you will be part of a compact and dynamic team based in Paris or working remotely, dedicated to developing impactful features for our users. Your responsibilities will encompass a variety of areas, including integrations with third-party financial systems like ERPs and billing tools, real-time data synchronization for millions of financial transactions, and managing our REST API. We prioritize data accuracy and reliability at scale, ensuring seamless financial data exchange between systems.We embrace continuous deployment (averaging 10 deployments per day) and foster a culture of pragmatism, ownership, and a growth mindset.For insights into our engineering practices, refer to this article.Your ResponsibilitiesIn your role at Upflow, you will:Design and implement complex, high-impact features from inception to completion.Work closely with the product manager and fellow engineers to convert business needs into technical solutions.Deploy clean, maintainable code to production on a daily basis.Engage in code reviews, offering and receiving constructive feedback.Diagnose and resolve intricate data and product challenges.Optimize application performance and scalability.

Join us as our inaugural Software Engineer for User Safety Tooling at amo!About the PositionAs a pivotal member of our User Safety team, you will architect and implement systems designed to safeguard our users, facilitate data collection, and ensure adherence to global regulations. You will become part of a dynamic and agile team that encourages creativity and innovation in developing impactful safety tools.At amo, we are dedicated to creating social applications that connect friends, and prioritizing user safety is integral to our mission. Collaborating with our User Safety lead, you will help construct the foundational infrastructure that keeps our community secure.Your ResponsibilitiesDesign and develop highly scalable, efficient, and resilient trust and safety platforms and tools, including data tracking pipelines.Enhance systems for improved data collection, compliance, and safety procedures.Develop APIs and integrate with third-party services.Create intelligent workflows to automate complex decision-making processes.Align product objectives with user-friendly platform development that meets operational requirements.Ensure uninterrupted safety services that can scale with our growing user base.About YouRequired QualificationsMinimum of 5 years experience in trust and safety tooling or content moderation systems.Strong proficiency in designing data structures, developing algorithms, and expertise in at least one programming language (Go, Kotlin, C, or C++).Excellent communication skills and a collaborative mindset.A demonstrated passion for user safety, human and AI moderation, and operational efficacy.Preferred QualificationsExperience with web development and frontend technologies.Familiarity with online safety regulatory requirements (DSA, etc.).Experience with machine learning models and data pipelines.Life at amoWe believe in setting our team up for success through collaboration, which is why we work together onsite five days a week.

About MorphoMorpho is at the forefront of Decentralized Finance (DeFi), operating a cutting-edge lending protocol that has recently garnered $50 million in funding from renowned investors, including Ribbit Capital, a16z crypto, and Coinbase Ventures. Our vision is to create an open lending network that democratizes access to the best financial terms for all. With over $10 billion in deposits, Morpho is rapidly redefining the standards of DeFi lending. We are expanding our team to solidify our position as a key player in the emerging internet-native financial ecosystem.Our MissionAt Morpho, we believe in empowering human ambition by providing open access to capital. The current financial landscape is fragmented, leaving many opportunities unseen and many individuals overpaying or entirely excluded. We strive to ensure that capital flows efficiently to where it is most needed, enabling anyone, anywhere, to access optimal terms.LocationThis role can be based in Paris or remotely (candidates located between -5 GMT and +2 GMT are encouraged to apply to ensure effective collaboration with our team).Our Work CultureWe thrive in a fast-paced environment where tackling challenging problems is the norm. As we navigate this evolving market, adaptability is crucial. We foster a culture of open communication where questioning decisions is encouraged. Our team maintains high standards while supporting each other to overcome obstacles and share knowledge. To learn more about our values, visit morpho.org/jobs.Role & ResponsibilitiesAs a Backend Engineer, you will be responsible for designing, building, and maintaining high-performance backend services and APIs that are crucial to Morpho’s user-facing features. Depending on your level of experience, you may take ownership of specific backend domains, mentor junior engineers, and contribute to cross-team initiatives.Your Responsibilities Include:Develop, deploy, and maintain backend services using TypeScript/Node and GraphQL, ensuring reliable and low-latency experiences for users.Design and optimize relational data schemas (PostgreSQL) for accuracy, performance, and maintainability.Collaborate with cross-functional teams including frontend, product, protocol, risk, and security to deliver seamless integrations.