Senior Software Engineer - FullStack (m/f/x)

Your Mission

We believe the future of marketing is word-of-mouth. Our trusted referral platform puts word-of-mouth marketing on autopilot by rewarding users (and affiliates) for sharing the product they love! The only all-in-one referral platform for B2B SaaS.

We’ve raised 6.3m€ total funding led by top-tier investors, and we’re now looking for a Senior Software Engineer (m/f/x) to help us realize our committed vision.

TL;DR

• Seed, GrowthTech
• Remote-first (+/-3 CET)
• Competitive salary + eVSOPS
  
  

Why join

• Unique growth opportunity: early-stage GrowthTech start-up backed by top-tier investors (6.3M€ total funding).
• Complex and interesting product: APIs, attribution models, recommendation engines, and more.
• Strong momentum: SaaS companies need cost-effective sales channels → we’re the solution.
• Build the engineering culture you’d recommend to your ex-colleagues.
• We onboard 15+ new customers every month and already reach 6M+ monthly users.
• Work with an experienced founding team (ex-Twilio, Pitch, Typeform).
  
  

What We’re Building

We help SaaS companies turn users into their best sales channel.

Our platform powers referrals, sharing & recommendations — used by millions monthly.

Tech stack includes:

• Frontend widgets embedded into customer apps.
• High-performance APIs for seamless integrations.
• Full customer portal for managing campaigns & analytics.
  
  

Under the hood: attribution models, recommendation engines, scaling millions of events — much more than a simple web app.

Job Description

We are currently looking for a Senior Full Stack Engineer (m/f/x).

• Stack: React
• NestJS
• Python
• AWS
• Work directly with stakeholders — no walls, no ticket factory.
• Build new features and improve existing systems.
• Pragmatic balance: Sometimes we ship fast to learn, sometimes we slow down to fix the foundation — you’ll help decide where to lean.
• Have real influence on architecture and product direction — not just coding tickets.
  
  

Required

About You

• Good communication skills and a friendly, collaborative attitude
• Good English skills (written & spoken)
• You know when “good enough” is right — and when to invest in quality
• Solid experience: React or similar, NestJS/Python or similar, and AWS is a must
• Comfortable debugging complex problems
• Contribute ideas, challenge assumptions, shape solutions
• Use AI tools wisely but don’t depend on them
  
  

Nice-to-haves

• Experience with mobile development (React Native, Flutter, etc.)
• Familiarity with data warehousing / analytics (e.g. Snowflake, ClickHouse, or similar)
  
  

Benefits

In the end, it’s all about the team and our culture. Understand why we love our job and see what it’s like to work at Cello in our People Playbook. We have some compelling perks and benefits.

About Us

⭐ We believe the future of marketing is word of mouth and are on a mission to supercharge product growth by making word-of-mouth rewarding. Cello is the world’s first all-in one referral platform that helps businesses harness their most passionate users and affiliates to drive word-of-mouth growth at scale.

Our platform allows users to share and discover any SaaS product with only a few clicks. By inspiring users to share the products they love, we are virtually reinventing how companies sell and market products.

Category leaders including Typeform, Moss and Join rely on Cello to put growth in the hands of their users.