Heartcore Portfolio Careers

Discover opportunities across our portfolio of companies who are enchanting the world through technology

Software Engineer



Software Engineering
Paris, France
Posted on Friday, March 1, 2024
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Software Engineer

Zefir accelerates life changes.
📝 Full-time (CDI) 🏡 (Paris 2e) or full remote (FR)

Hi, we are Zefir. 🏡

Zefir stands against the prevalent 'every man for himself' mentality in real estate. We've created the first collective sales platform that not only accelerates the connection between sellers and buyers but also fosters cooperation among all agents.

By dividing roles among various agents, ensuring fair compensation, evaluating performance, and centralizing a network of buyers and properties, we're setting a new standard for efficiency and transparency in the industry.


🎬Meet Gauvin, Software Engineer at Zefir

The Zefir engineering team is made of 11 talented profiles covering frontend, backend and infrastructure expertise. We are in search of a forward-thinking Software Engineer with strong backend expertise who will be instrumental in transforming product ideas into full-fledged product launches across our entire Acquisition perimeter.

You will play a key role in a high-impact team, influencing our Acquisition journey. Your responsibilities span the full spectrum of our users' experience, starting with leads initial engagement on our website to their transition to becoming new customers.

This role is perfectly suited for someone passionate about joining a fast-growing startup dedicated to creating outstanding products. You will be a member of a highly efficient team employing clean, well-conceived engineering architecture and design principles, striving to facilitate life changes for millions of European homeowners.


  • Focus on increasing our seller experience, building relationships with our several thousand monthly leads from their first brand interaction to starting their sales with Zefir.
  • Aim to build trust and improve customer satisfaction through a seamless selling experience based on self-service features and personalized interfaces.
  • Be key in your Business Unit, ensuring timely feature delivery and developing long-term strategies, mainly by improving interfaces like our website, qualification form, instant valuation process, customer dashboards and more.
  • Collaborate with your Engineering and Product Managers to prioritize and achieve key outcomes. Owning features from framing to delivery to impact our main success metrics like conversion rates (from initial lead to new customer) and lead time.
  • Write top-quality, cleaned, tested and maintainable code for rapid deployments, enhancing customer impact and internal engineering processes (100% coverage on critical path E2E tests, reducing our average time to review and so on).
  • Contribute to AI initiatives, participating in their development and ongoing enhancement.


  • Minimum of 3 years of engineering experience in global consumer products.

  • Lead technical development of performant and robust APIs in Node.js (typescript) using Nest.js and GraphQL. Develop frontend interfaces in React.js and Next.js.

  • Curiosity in AI is a bonus, with a preference for candidates with a desire to iterate quickly and with proven track record of deploying 1 LLM based feature creating value for end users.

  • Open-minded and fostering strong collaborative relationships with a range of expertises (Product, Ops, Growth, Brand etc).

  • Entrepreneurial drive with a proven history of transforming ambitious concepts into tangible realities.

  • Skilled in evaluating technologies, articulating insights, iterating on ideas, and making informed recommendations.

  • Proven ability to meet ambitious targets in a dynamic and fast-paced setting.

  • Ambition, a performance-driven attitude, and a positive mindset are essential.

  • Must be fluent in English, as all meetings and writings are conducted in English.


💵 Competitive salary
We pay at the market's top 75th percentile & use a transparent system to calculate salaries.

💸 BSPCE (Stock Options)
Every employee is an "owner" of the company & receives stock options, whatever their level.

💚 Healthcare plan
Covered at 100% with Alan Healthcare for you and your family.

🗺 Remote work
A lot of our Engineering team works remotely. Let's chat!

🏡 Amazing Amazing office in Sentier
Our office in the heart of the 2nd arrondissement offers a vibrant workspace.

🥗 Swile Card
Enjoy Swile restaurant vouchers with 11€ per working day.

🛴 Swile Mobility Pass
If you're not full-remote, 42€/month to cover your Navigo or other transportation options (scooters, electric bikes, etc.).

🎉 Monthly Mixers, Quarterly Celebrations
Exciting monthly team events, and quarterly all-hands day-long celebrations to mark our achievements.





👋 Recruitment Process

Screening interview: The initial interview for getting to know each other (⏱30’).

Written Questions: Written questions about your aspirations, your interest in Zefir, and a more specific question related to the role (📆to return within 3 days).

Onsite Interviews: Debrief on your written questions, interview with one of the co-founders, and an informal exchange with the team (⏱2h total). If you are fully remote, we'll arrange accordingly.

Do you want to join our team as our new Software Engineer? Then we'd love to hear from you!