Senior Backend Software Engineer - Performance

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:

Note: This position requires relocation to our Milan office.About SatispaySatispay aims to transform everyday payments by making them straightforward, equitable, and accessible to all. Our vision has expanded to redefine the future of financial transactions.We are a community empowering millions, united by a common mission to tackle significant challenges. Our approach is swift, bold, and collaborative, fostering an environment where innovation thrives and growth is continuous.As part of the Core Team, you'll engage with vital systems, overseeing interactions with banks, orchestrating payments, and offering the essential infrastructure for Identity and Access Management (IAM). The team also manages risk-related services, focusing on credit risk management and fraud detection.If you are eager to create something impactful that underpins all our product teams, you belong here.Your ResponsibilitiesIn your role as a Senior Backend Software Engineer within the Core Team, you will be pivotal in shaping the backbone of our payment platform. You will ensure the technical excellence and timely delivery of complex systems that influence various services and product teams across the organization.Your daily tasks will include:Core Platform Development: Contributing to the design and enhancement of critical systems like the Transaction Ledger, IAM, and Payment Orchestration, ensuring high performance, scalability, and functionality for seamless integration by product teams.Risk & Financial Services Optimization: Implementing and refining services for bank integrations, credit risk assessment, and real-time fraud detection, developing robust logic that safeguards our financial ecosystem.Technical Leadership: Leading technical analyses for cross-service projects, facilitating discussions, and producing comprehensive documentation (Smart Papers) to ensure clarity and robustness in your designs for stakeholders and engineering teams.

About H H focuses on advancing superintelligence through agentic AI. The company’s mission centers on automating complex, multi-step tasks that people usually handle, aiming for AI agents to help realize the full range of human potential. H seeks talented AI professionals who care deeply about responsible and safe development, as well as technical progress in agentic systems. The culture values openness, ongoing learning, and teamwork. Every team member’s input matters here. Product Engineering at H The Product Engineering team develops H’s Enterprise Platform, which provides customers with tools and services for essential operational needs. This platform supports large-scale computer-use agents, manages complex workflows, and offers a suite for observability, troubleshooting, and evaluation. Product Engineering connects AI research with practical applications and works closely with teams across the company.

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.

About Us Safran.AI, formerly known as Preligens, is a subsidiary of Safran Electronics & Defense, specializing in artificial intelligence solutions for analyzing high-resolution satellite imagery, full motion video (FMV) streams, and acoustic signals. Our innovative solutions are implemented in the aerospace, defense, and governmental sectors. Since 2016, our company has been developing sophisticated algorithms and software that automatically analyze, detect, and identify military-relevant objects from both commercial and governmental data sources. Following our integration into Safran in September 2024, Safran.AI is also playing a pivotal role in the group’s transformation by applying AI solutions to Industry 4.0 sectors. For example, automated image analysis through AI aids inspectors in identifying potential anomalies in critical components from digital images. At Safran.AI, innovation and the creation of a safer world are at the core of our mission. By joining us, you will collaborate with passionate, multidisciplinary teams (engineers, researchers, developers) among the industry's most talented professionals, all driven by a shared commitment to technological excellence. We provide a stimulating work environment where creativity and initiative are encouraged, and every idea matters. Your Mission, Should You Choose to Accept It As part of Project Robin, an innovative solution for monitoring strategic sites via satellite imagery and AI, already in production with several clients, you will join a team of 7 developers. Together, you will focus on evolving various backend modules with strong scalability and modularization challenges (data pipeline, database, API, orchestration, deployment). Note: The ability to obtain a Defense clearance is mandatory for this position. As a Senior Software Engineer, you will play a central role in bringing your technical expertise to the design, development, and implementation of our complex software solutions. Your responsibilities will include:→ Maintaining and evolving web applications (Python/FastAPI and JavaScript/React).→ Designing, developing, and maintaining our backend infrastructure and automated pipelines (Python, Airflow, PostgreSQL).→ Collaborating closely with all teams and subject matter experts to understand end-user needs.

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.

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

Please note that this position requires relocation to our Milan office.About SatispaySatispay is dedicated to transforming the way everyday payments are made, striving to make transactions simple, equitable, and accessible for all. Our vision has evolved to redefine the future of finance.We are a community of innovators empowering millions, united by a common goal to address significant challenges. Our journey is just beginning. We are rapid in our actions, bold in our ideas, and foster a culture of mutual trust and continuous learning.If you seek more than just a job and wish to make a lasting impact alongside a talented team, you’ve come to the right place.Key ResponsibilitiesAs a Senior Backend Software Engineer within our Business Team, you will be instrumental in revolutionizing digital welfare payments - managing everything from employer benefits to intricate product solutions. You will enhance the complete experience for both employers and employees, ensuring sustained satisfaction. Your role will encompass technical leadership, quality assurance, and the delivery of complex systems that enable thousands of employers to effectively manage their corporate welfare solutions. Here’s what your typical day will include:Design Multi-Service Solutions: Undertake technical assessments for medium to large-scale projects impacting various services in the Employer domain. You will architect robust, highly-available solutions with a focus on scalability, security, and maintainability that are core to our welfare products.Maintain Technical Quality: Implement comprehensive testing strategies that balance automation and manual efforts, overseeing gradual rollouts with meticulous monitoring to ensure that welfare distributions remain accurate and dependable.Proactively Resolve Challenges: Anticipate and address technical obstacles, fostering knowledge sharing across the organization. You will navigate the unique complexities of B2B registration processes and high-volume benefit distributions while ensuring code quality through diligent reviews.Ownership and Execution: Take full ownership of your projects from inception to completion, delivering functionalities that genuinely cater to user requirements - from the moment an employer registers to the moment an employee utilizes their welfare benefits through seamless backend integration.

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.

About Mistral AIAt Mistral AI, we harness the transformative potential of AI to streamline tasks, enhance creativity, and optimize learning experiences. Our cutting-edge technology seamlessly integrates into everyday workflows.We are committed to democratizing AI through high-performance, open-source solutions and state-of-the-art models. Our comprehensive AI platform is tailored to meet the diverse needs of enterprises, available both on-premises and in the cloud. Notably, our offerings include Le Chat, the AI assistant designed to elevate both personal and professional life.As a dynamic and collaborative team, we are passionate about AI's potential to create a significant societal impact. Our diverse workforce thrives in competitive environments and is dedicated to fostering innovation. With teams spread across France, the USA, the UK, Germany, and Singapore, we embody creativity, humility, and a strong team spirit.Join us in shaping the future of AI and make a meaningful impact. Discover more about our culture at https://mistral.ai/careers.Role OverviewWe are in search of enthusiastic and talented software engineers to join our team. As a Backend Engineer, you will play a crucial role in developing the core systems that power our key products: AI Studio, Le Chat, and Mistral Code. Your contributions will shape the way users and developers interact with our AI platform at scale. You’ll focus on building reliable, high-performance backend systems and APIs that cater to millions of users and developers. Your work will greatly enhance both developer and user experiences, ensuring they are engaging, efficient, and intuitive. We welcome engineers of all levels, from recent graduates to seasoned professionals, who are eager to learn, collaborate, and deliver impactful solutions.Key ResponsibilitiesDepending on your expertise, you will engage with critical components of our technology, which may include:Backend Development- Design, develop, and maintain scalable and robust backend features and APIs using modern frameworks.- Ensure high performance and reliability across our distributed systems.

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 UsAt MARGO, our consultants focus on what truly matters: complex projects that blend intellectual challenges with significant business impact. We partner with leading players in finance, industry, and technology to design and develop high-performance software solutions, including distributed architectures, cloud platforms, real-time systems, and large-scale critical applications.Why Join Our Software Engineering Practice?You will work alongside an experienced team led by Paul Blois, Practice Manager at MARGO for 5 years, and Prosper Gratian, Practice Lead and C++ Developer. Collaborating with them means benefiting from in-depth company knowledge, receiving close mentorship for your career growth, and contributing to demanding IT projects that have a high impact on our clients.Your Responsibilities- Design, develop, and optimize high-performance C++ components.- Participate in the migration of critical applications.- Contribute to the establishment of an internal framework for cross-functional applications.- Ensure code quality, performance, and maintainability.- Engage in code reviews, continuous improvement, and sharing best practices.Technical Stack: Modern C++ (C++17/20)Associated tools and technologies: Kafka, ElasticSearch, Git, CI/CD, AWS.Challenges: Performance, robustness, and managing large data volumes (processing 9 billion messages).Desired ProfileWe are looking for a passionate C++ developer with an interest in real-time systems and financial markets, eager to thrive in complex, high-performance environments.- Master's degree (engineering school or university).- Strong skills in C++, multithreading, performance optimization, and development best practices (SOLID, unit testing).- Experience in critical systems development and real-time data stream processing.

Join us as a pivotal member of the Backend team at amo, where you'll play a critical role in shaping our infrastructure. In the initial months, you will collaborate closely with the team and gradually take charge of key components and features. At this early stage of our journey, we are in search of adaptable engineers who are eager to contribute across multiple facets of our company’s foundation.We appreciate team members who dive deeply into their areas of expertise, fostering a culture of subject matter mastery within our team. This dedication to specialization is a core expectation for every engineer.Our backend team is responsible for both server-side operations and the backbone of the client, as we believe a unified team can more effectively manage topics like networking, data modeling, management, and synchronization.As a Backend Engineer, your daily responsibilities will include:Building the FutureYou will develop robust systems designed to handle significant traffic, vast amounts of data, and an unparalleled rate of scaling. Your toolkit will include cutting-edge technologies, elegantly crafted code, and systems built for seamless horizontal scaling.Ensuring Cross-Platform CohesionBeyond server-side development, you will be involved in the enhancement and maintenance of a Rust component shared between iOS and Android. This component primarily focuses on networking, data synchronization, and data-oriented feature logic, benefiting from a single codebase. You will collaborate with mobile engineers to ensure a consistent experience across platforms and bridge the gap between mobile development and backend architecture for a cohesive user journey.Innovative Feature DevelopmentEngage in brainstorming sessions to design and implement unique features that distinguish us in the marketplace.Commitment to Continuous ImprovementWe value mutual learning and staying updated with industry trends and emerging technologies, encouraging fresh ideas and contributions to our culture of continuous improvement.Ownership of Your DomainYou will monitor analytics and manage system incidents, taking ownership of your responsibilities and proactively addressing issues and bug fixes.

Join Vibe and Transform Streaming TV AdvertisingAt Vibe.co, we are revolutionizing the way brands connect with audiences in today’s streaming landscape. We see streaming TV not merely as a platform for brand awareness but as a powerful performance marketing channel offering immense potential. Our mission is to build the infrastructure that will unlock this $100 billion opportunity.Vibe.co delivers an Audience First Streaming TV Advertising solution, enabling marketers to harness the full power of TV as a growth channel. Our comprehensive platform integrates precision audience targeting, AI-driven insights, real-time campaign optimization, and effective incrementality measurement, equipping brands of all sizes with the same level of accuracy and transparency they expect from digital channels.With the trust of over 10,000 brands and coverage reaching more than 120 million households across 500+ applications and channels, Vibe.co boasts an impressive average return on ad spend of 250% and a 20% lift in sales. In under two years, we achieved a remarkable $100 million revenue run rate, placing us among the fastest software companies to reach this milestone.Supported by renowned investors such as Hedosophia, Elaia, and several angel investors including Carolyn Everson of The Walt Disney Company, we are proud to be recognized as the leading platform in streaming TV advertising. Founded in 2022, Vibe.co is at the forefront of bringing advanced performance marketing to the rapidly growing media sector.Your Role as a Senior Software Engineer - SREAs part of our Infra Platform team, you will play a critical role in the engineering backbone of Vibe. This team is responsible for hosting, provisioning, observability, CI/CD, internal tools, security, and compliance. Every product and platform team relies on the solutions we develop.You will report directly to our Lead Platform Engineer and collaborate closely with the team to establish the technical direction and uphold the infrastructure standards that are vital for the company’s success. Given the rapid growth of our platform, which is currently utilized by over 60 engineers daily, we are seeking a candidate who will take ownership and drive the scaling process. You will engage with infrastructure that processes over 600,000 queries per second, ensuring optimal latency and performance.

About UsAt Harmattan AI, we are pioneering the development of autonomous and scalable defense systems. With a recent $200 million Series B funding round that has raised our valuation to $1.4 billion, we are poised for growth and are seeking talented individuals to join our mission of delivering cutting-edge systems to allied forces.Our guiding principles are centered around creating impactful technologies, striving for excellence, setting ambitious objectives, and confronting complex technical challenges head-on. We thrive in a dynamic environment where accountability, precision, and execution are critical.About the RoleWe invite a passionate Backend Software Engineer to become a vital part of our C2 Core team in Paris. In this role, you will be instrumental in developing the foundational architecture for our advanced tactical Command and Control (C2) application. You will operate in a high-stakes, technical environment where low latency, high availability, and secure data management are crucial.Your primary responsibilities will involve ensuring seamless data flow for real-time telemetry, high-bandwidth video streams, and mission commands between our fleet of robots and the internal C2 components, including the Common Operational Picture (COP) and Mission Planner. This system is designed for deployment on ruggedized tactical PCs in field environments often characterized by limited network connectivity.

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.

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 Dailymotion as a Senior Backend Engineer and play a pivotal role in developing our core components. In this fully remote position, you will work collaboratively with cross-functional teams to design, build, and maintain scalable backend systems that power our video platform.

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.

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!