Full Stack Developer; RoR & React Native

Senior Full Stack Developer

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 exists to help you reach your greatest potential. And positively impact the world. Influencer Marketing is today described as a revolution, a 20B$ 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 Influencer Marketing.

We are building a new B2C product for the next generation of content creators, and we need a strong technical partner to make it happen. As a Senior Full Stack Developer, you will work hand-in-hand with your Development colleagues, Product Designer and Product Marketing Manager to design, build and ship a product that creators love to use - across web and mobile.

You won't just be writing code; you will have a direct impact on architecture decisions, product quality and the pace at which we deliver value to our users. This is an early-stage product with serious ambition, and you'll play a foundational role in shaping it.

Together with your Development colleagues, Product Designer and Product Marketing Manager, you will be responsible for the technical execution and quality of this new B2C product:

• Full Stack Development:
  Build and maintain features end-to-end - from Rails API endpoints and background jobs to React Native screens and components - ensuring a seamless experience across iOS and web.
• Architecture & Code Quality:
  Contribute to architecture decisions, advocate for simplicity and maintainability, and uphold high standards through code reviews, testing and clean abstractions.
• Platform Integrations:
  Work with social media APIs (Instagram, Tik Tok, Facebook), payment systems (Stripe) and third-party services, handling OAuth flows, webhooks and data synchronization reliably.
• Infrastructure & Deployment:
  Participate in our deployment pipeline (Kamal on GCP), background job processing, monitoring and observability — keeping the product stable and performant in production.
• Cross-Functional Collaboration:
  
  Work closely with product and design to turn user needs into technical solutions, synchronize with the broader Kolsquare engineering team to leverage shared data and mutualize features when possible.

You have a minimum of 3 years of experience in Ruby / Rails, and relevant experience with React (preferably Native). You enjoy shaping the technical direction of early-stage projects and laying down a robust foundational architecture. You are autonomous, organized and proactive, with demonstrated ability to prioritize and manage multiple projects in a fast-paced environment. You know how to leverage AI to optimize your output, in terms of quality and quantity.

You are empathetic and you love working with people from different backgrounds. You have excellent communication skills, with the ability to collaborate effectively across teams. You are fluent in English.

We are meant to work together if you are a passionate person and you have determination to reach any goal. You are curious and want to learn, improve and gain responsibility. You want more than just a job! Kolsquare is a benefit company, with a general ambition that goes beyond our profitability goals: positively impact the world.

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.

More info about culture here in our Culture Book.

What do we offer?

• You can be based anywhere in Europe.
• 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.