Senior Backend Developer

• Be Responsible in your actions
• Pursue Growth & Learning
• Be passionate and determined
• Share your Power, Knowledge & Wealth
• Build Authentic relationships

We cultivate a culture of inclusion for all employees that respects their individual strengths, views, and experiences. We believe that our differences enable us to be a better team - one that makes better decisions, drives innovation, and delivers better business results., We are looking for an experienced Senior Backend Developer to join our team and help build, scale, and maintain our SaaS platform. You will play a key role in designing robust backend systems, improving performance, and delivering high-quality features that power our product.

Backend Development & Feature Delivery (50%) : Design, develop, and maintain backend services and APIs using Ruby on Rails. Implement new features for the SaaS platform, write clean and maintainable code, and ensure the scalability and performance of the application.

System Architecture & Performance Optimization (30%) : Contribute to backend architecture decisions, improve system scalability, and optimize database queries and search performance using Elasticsearch. Ensure the platform remains reliable and performant as the product grows.

Collaboration, Code Quality & Technical Leadership (20%) : Collaborate with product, frontend, and DevOps teams to deliver high-quality features. Participate in code reviews, maintain testing standards, contribute to CI/CD processes, and support best engineering practices within the team.

• Strong experience with Ruby on Rails in production environments
• Solid experience designing and maintaining RESTful APIs
• Hands-on experience with Elasticsearch or search systems
• Strong knowledge of relational databases (MySQL preferred) and query optimization, * Experience working on SaaS platforms or high-scale applications
• Familiarity with cloud environments (GCP) and CI/CD pipelines
• Experience with performance optimization, background jobs, and distributed systems

• Full flexibility: full remote work with European hubs and 400+ coworking spaces worldwide.
• Monthly and quarterly highlights in person to get together with other Kolsquarians for great team building events.
• A package linked to the market that will not be based on your location.
• The stability and resources of a profitable group, with the agility of a scale-up.
• Continuous training opportunities and career development support.

Kolsquare is the #1 Influencer Marketing software solution in Europe, used by marketing professionals for managing KOL Marketing campaigns (K.O.L for Key Opinion Leaders, aka Influencers), and designed to optimize brand communication strategies in response to new digital challenges. Using our technology, professionals can identify the best KOL profiles, fully manage their KOL Marketing campaigns and measure their results and performances. Kolsquare offers hundreds of customers (Coca-Cola, Danone, Publicis, Orange, Sézane, Decathlon, etc.) the latest Big Data, AI and Machine Learning technologies to activate inspiring and genuine partnerships with over 3M KOLs (Key Opinion Leaders) with more than 5,000 followers in 180 countries on Instagram, TikTok, Twitter (now X), Facebook, Snap and YouTube. In 2024, Kolsquare joined the team.blue group, one of the largest private tech companies in Europe, with a culture of innovation and excellence, to further fuel its impressive track record of outstanding profitable growth., Kolsquare exists to help you reach your greatest potential. And positively impact the world. Influencer Marketing is today described as a revolution, a 30B$ market that is a major transformation in the media and digital world. It has also become a real gold mine, creating high hopes but also bringing its share of myths and legends. Everyone knows it works and can have an amazing impact on brand awareness or customer acquisition, but not everyone knows exactly how to do it. At Kolsquare, we firmly believe in this new media and are convinced that it's the best way for ideas, people and organisations to grow and reach their greatest potential. We also believe that it's a great way to create positive impacts for a better world. Our mission is therefore to give everyone access to the power of KOL Marketing., * You want to join an adventure more than a job! Kolsquare is a benefit company, with a general interest ambition that goes beyond our profitability goals: positively impact the world.