Full Stack Developer (RoR & React Native)

About Kolsquare

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 Sézane, Decathlon, Coca-Cola, Danone, Publicis, Orange, etc.) and NGOs Génération Numérique, Marion La Main Tendue, Surfrider Foundation, etc.) the latest technologies to activate inspiring and genuine partnerships with over 3M Influencers in 180 countries on Instagram, TikTok, YouTube, Facebook and Twitter (now X).

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.

OUR MISSION

Kolsquare is a Benefit Company, certified B-Corp in 2024.

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.

YOUR MISSION

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 the 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.

YOUR ROLE

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, TikTok, 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.

YOUR PROFILE

• 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

KOLSQUARE CULTURE & VALUES

• Deliver WOW
• 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.

📌 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.

Kolsquare is Europe’s leading Influencer Marketing platform, a data-driven solution that allows brands to scale their KOL Marketing strategies and implement authentic partnerships with KOLs (Key Opinion Leaders).

Kolsquare’s technology enables marketing professionals to easily identify the best Content Creators’ profiles by filtering their content and audience, and to build and manage their campaigns from A to Z, including measuring results and benchmarking performance against competitors.

Kolsquare has built a thriving global community of influencer marketing experts, and offers hundreds of customers (Coca-Cola, Netflix, Sony Music, Publicis, Sézane, Sephora,, Lush, Hermès…) the latest Big Data, AI and Machine Learning technologies to drive inspiring partnerships, tapping into an exhaustive network of KOLs with more than 5,000 followers in 180 countries on Instagram, TikTok, X (Twitter), Facebook, YouTube and SnapChat.

As a Certified B Corporation, Kolsquare has been pioneering Responsible Influence by championing transparency, ethical practices, and meaningful collaborations to inspire change.

Since October 2024, Kolsquare forms part of Team.Blue, a leading digital enabler for businesses and entrepreneurs across Europe made up of over 60 successful brands in the fields of web hosting, domains, e-commerce, online compliance, lead generation, application solutions, and social media.