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Senior Software Engineer (C++, OS Internals)

Nexthink

Full-time|Hybrid|Paris

Join the dynamic Nexthink Engineering department, where you will be an integral part of a team dedicated to developing the Collectors—advanced endpoint agents utilized by millions of employees. These Collectors play a pivotal role in extracting and interpreting vital information from operating systems, sending it to our powerful data analytics systems, and e…

Feb 27, 2026

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C++/C Development Engineer (M/F)

Alten

Full-time|On-site|Paris

Role overview Alten is hiring a C++/C Development Engineer for its Rail department in Paris. The team tackles projects that shape the future of transportation, with a focus on practical engineering and collaborative problem-solving. What you will do Design, develop, and maintain software using C++ and C for rail sector projects Work alongside fellow engineers to deliver dependable technical solutions Take part in technical discussions and contribute to process improvements Requirements Keen interest in software development and transportation technology Openness to learning and adapting to new technical challenges Collaborative mindset and proactive attitude Location This role is based in Paris.

Apr 24, 2026

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C++ Developer - High Performance | MARGO Software Engineering

margo-group

Full-time|On-site|Paris

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.

Jun 12, 2025

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C# Developer | Software Engineering Practice at MARGO

MARGO Group

Full-time|On-site|Paris

About UsAt MARGO, our consultants focus on what truly matters: intricate projects that combine intellectual challenges with real 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 the Software Engineering Practice?You will be part of a team led by Paul Blois, our Practice Manager for the past five years. Collaborating with him means benefiting from his in-depth knowledge of the firm, receiving close mentorship for your personal development, and contributing to demanding IT projects that have a significant impact on our clients.Your ResponsibilitiesJoin an international team of electronic trading experts dedicated to developing high-performance market solutions. Your tasks will include:- Designing and enhancing trading bots capable of executing complex real-time strategies.- Optimizing performance (latency, multithreading) and managing high data volumes.- Ensuring robust C# code, adhering to SOLID principles, with testing and code reviews.- Contributing to the management of Cloud infrastructures (Azure) and data security.Candidate ProfileWe are looking for a C# developer passionate about real-time systems and interested in market finance, eager to thrive in complex, high-performance environments.- Educational background: Master’s degree (engineering school or university).- Strong skills in C#, multithreading, performance optimization, and best development practices (SOLID, unit testing).- Experience in developing critical systems, processing real-time data streams; experience in finance is a plus.- Ability to solve complex technical problems and collaborate with multidisciplinary teams.- Enthusiasm for demanding environments.

Feb 28, 2020

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C++ Developer - Front Office | Software Engineering Practice

margo-group

Full-time|On-site|Paris

About UsAt MARGO, our consultants focus on what truly matters: complex projects that combine intellectual challenge with real business impact. We support leading players in finance, industry, and technology in designing and developing high-performance software solutions, including distributed architectures, cloud platforms, real-time systems, and large-scale critical applications.Why Join the Software Engineering Practice?You will be part of a team led by Paul Blois, Practice Manager at MARGO for 5 years, and Prosper Gratian, Practice Lead and C++ Developer. Working alongside them provides unparalleled insight into the company, close mentorship for your development, and the opportunity to contribute to demanding IT projects with significant impact for our clients.Your ResponsibilitiesYou will engage in the development of a core application for the front office of an investment bank, a booking tool that provides positioning and performs real-time risk calculations. This tool is essential for the trading floor and other data consumers such as risk management, accounting, and back office. You will be involved in:- Developing new features to enhance performance and reduce latency.- Optimizing code to ensure peak performance, particularly in multithreading and latency management.- Collaborating with front office teams and other client departments.Technical Challenges: Performance, multithreading, and latency management.Rich Functional Environment: You will work in a rich functional environment, interacting with several key departments.Tech Stack: C++ 17

Feb 10, 2025

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C# Developer - Algorithmic Trading | MARGO Software Engineering Practice

margo-group

Full-time|On-site|Paris

Who are we?At MARGO, our consultants engage in what truly matters: complex projects that blend intellectual challenges with real business impact. We collaborate 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 the Software Engineering Practice?You will be part of a newly established team led by Paul Blois, Practice Manager at MARGO for the past 5 years. Working alongside him means gaining in-depth knowledge of the company, receiving close guidance in your professional development, and contributing to demanding IT projects with significant impacts for our clients.Your missionsYou will join a newly formed team at a leader in the energy sector, tasked with designing an algorithmic trading platform dedicated to battery energy storage. This strategic project aims to stabilize the electrical grid by injecting energy during peak consumption.As a C# Developer, you will contribute to building a robust, scalable, and high-performance solution capable of managing assets across Europe and the United States.Your responsibilities include:- Trading Engine Development: Design the software components enabling algorithmic trading in Intraday markets.- Asset Optimization: Implement and run complex optimization models (considering weather, market prices, and consumption profiles).- Backtesting Platform: Develop a secure and efficient environment for traders to test and validate their algorithmic strategies.- Scalability & Evolvability: Participate in the architecture of a solution initially focused on batteries but eventually designed to integrate the entire renewable energy portfolio (wind, hydro, thermal).

Feb 5, 2026

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Junior Backend Engineer - C#

Shift Technology

Full-time|On-site|France - Paris

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.

Apr 15, 2026

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Software Engineer Intern at Bigblue | Paris

Bigblue

Internship|On-site|Paris

Paris | CDI | Français & Anglais courants requisLe e-commerce connaît une croissance fulgurante — cependant, les marques indépendantes peinent encore à offrir une logistique aussi efficace que celle d’Amazon. Chez Bigblue, nous avons pour objectif de transformer cette réalité.Notre mission est d'aider les marques à croître plus rapidement tout en leur offrant une expérience client exceptionnelle, grâce à des opérations logistiques de premier ordre.Depuis 2018, nous développons une plateforme technologique qui propulse déjà plus de 500 marques, allant de jeunes entreprises DTC à des noms renommés tels que MUJI, Aigle et Cabaïa.Avec plus de 110 collaborateurs à Paris, Madrid et Londres, notre propre WMS Atlas, ainsi qu’un réseau de 7 entrepôts à travers l’Europe, nous relevons les défis logistiques que d'autres n'osent même pas envisager. Le résultat : une logistique plus rapide, plus intelligente et plus écologique.Énergisés par plus de 20 millions de dollars de financement et choisis par les futurs leaders du e-commerce, nous passons à la vitesse supérieure : 10 millions de commandes à traiter en 2024… et ce n’est que le début.Nous sommes en quête de talents pour écrire la prochaine page de cette aventure ambitieuse avec nous.

Aug 23, 2022

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Senior C++ Developer - Montpellier - H/F

iliad-free

Full-time|On-site|Paris

Role overview iliad-free seeks a Senior C++ Developer to join the team supporting its services. The role centers on designing, building, and improving software solutions. This position is located in Paris. What you will do Design and develop software using C++ Write code with a focus on performance and reliability Work closely with colleagues from different teams to deliver strong products Play a part in projects that move our technology and services forward Requirements Solid experience in C++ development Skilled at collaborating to solve complex technical challenges Driven to build effective software solutions

Apr 21, 2026

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Senior Cross-Platform Software Engineer

GoPro, Inc.

Full-time|Hybrid|Paris

Location: Flexible (Paris Issy-les-Moulineaux). This role provides the opportunity to work from home while being close to an office location. The Role As a Senior Cross-Platform Software Engineer at GoPro, you will play a pivotal role in enhancing and sustaining the core software that powers GoPro’s software ecosystem. You will be tasked with developing and refining software and tools that are utilized in mobile applications, desktop software, the GoPro cloud, and GoPro cameras. We are looking for a candidate with expertise across multiple platforms, programming languages, tools, and build systems who thrives in an agile software development environment. In this position, you will create high-quality, thoroughly tested libraries and tools that are compatible across various platforms. Collaborating with platform-specific teams, you will integrate these libraries and tools to construct a unified software ecosystem designed to help users capture and cherish their most treasured photo and video moments. What You Will Do Design, build, test, and maintain cross-platform software for client application development teams. Engage with a diverse array of platforms (desktop, mobile, cloud, embedded). Explore various domains, including media file format support, graphics programming, AI integration, platform abstractions, and algorithm development. Continuously enhance the quality and reliability of the code. Advance the software engineering system for improved software management, integration, and build processes. Skills We’re Excited About Bachelor's degree in Computer Science, Engineering, or a relevant field. 3-5 years of experience in cross-platform software development using C++ and at least one additional programming language. Excellent communication skills, both written and verbal. Bonus Points For Proficiency in modern C++ (C++11 and newer). Familiarity with the CMake build system. Experience developing libraries and applications for Windows, macOS, Linux, iOS, and Android. Strong skills in git, including GitHub Actions. Proficiency in Java, Kotlin, Swift, Objective-C, C#, and Python. Experience with Xcode, Visual Studio, and Android Studio. Background in working with photo, video, or audio media. A passion for photography and videography. Why Work With Us?

Feb 9, 2026

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C/C++ Developer - Financial Markets (H/F)

Meritis

Full-time|On-site|Paris

Meritis seeks a C/C++ Developer in Paris to strengthen its financial markets team. This role focuses on building and enhancing applications that underpin finance operations. Key responsibilities Design, develop, and maintain software using C and C++ for financial systems Optimize application performance and resolve technical issues as they arise Work closely with colleagues from various teams to deliver effective solutions Location This position is based in Paris.

Apr 27, 2026

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Software Engineer Intern at Maki | Paris

Maki

Internship|On-site|Paris

About UsMaki is revolutionizing the recruitment landscape with cutting-edge autonomous AI hiring agents. Our technology seamlessly manages the entire hiring process—from sourcing and screening to interviewing and selection—allowing HR teams to focus on what truly matters: finding exceptional talent.Leading brands such as H&M, BNP Paribas, and FIFA trust Maki to streamline their hiring processes, automating up to 90% of screening and interviewing, thereby tripling the speed of hiring and reducing employee turnover by 20 to 30%.At Maki, we are not just another HR tool; we are pioneering the next wave of AI-driven talent acquisition.Your Role at MakiAs a Software Engineer Intern, you will collaborate with our engineering team to design and enhance the AI systems that power Maki. Your role will involve contributing meaningful features to our product, learning rapidly, and shaping the application of modern AI in large-scale recruitment.

Jan 19, 2026

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Lead Principal C++ Software Developer - Network Diagram

Esri

Full-time|On-site|Paris, FR

Join Esri as a Lead Principal C++ Software Developer focusing on Network Diagram technologies. In this pivotal role, you will design, develop, and optimize software solutions that enhance spatial data visualization and management. You will collaborate with cross-functional teams to deliver robust applications and contribute to innovative solutions that push the boundaries of geographic information systems (GIS).

Mar 24, 2026

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Senior Software Engineer - Paris

Swile

Full-time|On-site|Paris, France

At Swile, we are committed to enhancing professional experiences through innovative product solutions that alleviate daily challenges and elevate employee satisfaction. Our cutting-edge offerings in Fintech, Travel, HR, and Employee Benefits serve over 5.5 million users across 85,000 companies in France and Brazil, making a significant impact on the workplace.As a Senior Software Engineer, you will play a pivotal role in problem-solving, blending creativity with technical expertise. Your focus will be on delivering high-quality solutions swiftly and effectively, addressing both business and engineering challenges with innovative strategies rather than being restricted to specific technologies.

May 23, 2024

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Senior Software Engineer - Paris

hcompany

Full-time|On-site|Paris

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.

Apr 14, 2026

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Senior Software Engineer - Calibration Software

Alice & Bob

Full-time|On-site|Paris

Alice & Bob is pioneering the development of the first universal, fault-tolerant quantum computer aimed at tackling some of the most challenging problems in the world. Our innovative quantum computer is based on a revolutionary type of superconducting qubit known as the Schrödinger cat qubit. Unlike traditional superconducting platforms, cat qubits possess the remarkable capability to autonomously implement quantum error correction!We are leading the quantum revolution, standing shoulder to shoulder with industry giants like Google and IBM, and we are rapidly expanding following our successful €100 million funding round in 2025 dedicated to advancing our unique technology.With over 100 talented individuals, including physicists, PhD students, engineers, and seasoned business professionals, we are united in our quest to achieve our ambitious vision. Are you ready to join us as a quantum pioneer and help reshape the future?About the Role:The Calibration Team is tasked with automating the calibrations of our Quantum Processing Unit (QPU) to maximize its performance and ensure its operational reliability. As a Senior Software Engineer within this team, you will be instrumental in architecting the automatic calibration software. You will collaborate closely with quantum scientists to develop, maintain, and enhance the calibration processes. Additionally, you will work alongside other software engineers across the organization to facilitate seamless integration of your team's software with other in-house software components.

Aug 8, 2025

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C++ Tech Lead

Altersolutions

Full-time|On-site|Paris

Join Altersolutions as a C++ Tech Lead in the vibrant city of Paris. In this pivotal role, you will spearhead projects, mentor junior developers, and drive the evolution of our C++ applications. Your expertise will be crucial in ensuring that our software solutions are not only robust but also cutting-edge.As a leader, you'll collaborate closely with cross-functional teams to design, develop, and implement high-performance software solutions that meet our clients' needs. If you are passionate about technology and thrive in a dynamic environment, we want to hear from you!

Jan 3, 2025

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Senior Software Engineer - React & Java

believe

Full-time|On-site|Paris

believe is hiring a Senior Software Engineer with a focus on React and Java for its Paris office. This role centers on creating web applications that deliver effective user experiences. Key responsibilities Design and build web applications using React and Java Collaborate with colleagues across different teams to understand requirements and deliver solutions Support ongoing enhancements to software products Location This position is based in Paris.

Apr 28, 2026

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Senior Software Engineer at The Flex | Paris

The Flex

Full-time|On-site|Paris

Join our innovative team that is transforming the future of global living.At The Flex, we envision a world where renting a home is instant, intelligent, and seamless—much like booking a ride. Our mission is ambitious: to empower anyone to live anywhere, anytime, without hassle.Driven by Base360.ai, our unique automation engine, we are crafting the operating system for modern renting—integrating property data, streamlining operations, and facilitating smooth stays across continents.If you are passionate about complex systems, automation, and developing software that has real-world applications, this position offers you the opportunity to take ownership and make a significant impact. What You'll CreateAs a Senior Software Engineer, you will design, develop, and scale essential components of The Flex platform—from core services and APIs to automation workflows and real-time systems.You will work with considerable autonomy, managing problems from start to finish and directly influencing architectural decisions while remaining deeply engaged with production code.This role is for engineers who prioritize impact over meetings and take pride in constructing systems that are reliable, elegant, and scalable. Your ObjectivesDevelop Core SystemsCreate and maintain scalable services that enhance bookings, payments, availability, pricing, and guest experiences.Design Robust APIsEstablish clean, well-structured APIs that connect Base360.ai with internal tools and external partners.Automate OperationsConstruct event-driven workflows that eradicate manual tasks and unlock operational efficiencies.Deploy with AssuranceImplement and manage cloud-native infrastructure on AWS with an emphasis on reliability, security, and performance.Tackle Meaningful ChallengesEngage in real-time booking synchronization, pricing intelligence, keyless access systems, AI-driven alerts, and live operational dashboards.Collaborate for SuccessPartner closely with product, data, and operations teams to transform complex requirements into straightforward, effective systems. Ideal Candidate ProfileExtensive experience in building production systems with Node.js, React, and AWS.Solid understanding of software design principles and best practices.Proficient with CI/CD practices and tools.Strong communication skills and a collaborative mindset.

Jan 29, 2026

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Senior Software Engineer at vusiongroupsa | Paris

vusiongroupsa

Full-time|On-site|Paris

Join our dynamic team at vusiongroupsa as a Senior Software Engineer, where you'll have the opportunity to contribute to innovative projects that shape the future of technology. We are looking for a skilled professional who can bring their expertise in software development, work collaboratively with our R&D department, and drive excellence in our engineering practices.

Apr 13, 2026

Senior Software Engineer at believe | Paris

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