Software Engineer - Full Stack

Role overview

Cello builds the revenue growth infrastructure that helps modern digital businesses acquire, keep, and monetize customers more effectively. The company turns word-of-mouth into a trackable growth channel designed for the AI era and has secured $10.3M in total funding from leading investors. It is hiring a Senior Software Engineer - Full Stack (m/f/x) to contribute to its next stage of growth.

Why this opportunity stands out

• The company is a seed-stage GrowthTech scale-up backed by $10.3M from top-tier investors.
• The product goes beyond a standard CRUD application, with work spanning APIs, attribution systems, MCP integration, AI-driven recommendation engines, and assistant experiences.
• The platform already has strong real-world traction, adding more than 30 new customers each month and serving over 10 million end users monthly.
• The team is intentionally small, giving you real influence over engineering decisions and product direction.
• The role covers the full stack, from frontend widgets and backend services to infrastructure and data pipelines, so the work stays varied.
• The company actively evaluates and adopts useful new technologies and AI tools, because its customers are doing the same.
• The team works remotely first, while meeting in person regularly for company-wide and engineering gatherings.
• The founding group includes serial founders and experienced operators from Twilio, Wise, and Skype.

What the company is building

Cello helps SaaS businesses transform users and partners into a sales channel through referrals, sharing, and recommendations. More than 10 million end users interact with the system every month.

The product appears inside customer applications, which means the code must run reliably in environments the team does not control. It also includes developer-facing APIs and a customer portal for campaign management and analytics.

Behind the scenes, the platform handles attribution across complex user journeys, AI-based recommendation logic, multi-tenant infrastructure for hundreds of customers, and processing at the scale of millions of events. The work is more complex than a typical referral tool.

The product is used by a wide range of developers, from enterprise engineering teams to solo founders working with AI coding agents. Adapting to how developers build today and making sure the product fits smoothly into those workflows is a key part of the challenge.

What you will do

• Work with the core stack, including React, NestJS, and Python.
• Begin with clearly defined tasks and gradually take on broader ownership.
• Build new features, resolve bugs, and expand your responsibility as you become familiar with the product.
• Collaborate with experienced engineers who will support your growth while still expecting you to work independently.
• Use AI tools as part of the day-to-day workflow to work faster and learn more quickly.

Who we are looking for

• Strong written and spoken English skills.
• Some hands-on experience with React or a similar frontend framework, plus NestJS, Python, or a comparable backend technology.
• Evidence that you have built something real, even if you do not have many years of experience yet.
• A strong desire to learn, with curiosity and energy compensating for limited experience.
• Comfort using AI tools to increase productivity, while still being able to write reliable code independently.
• Interest in learning the product and domain deeply, not only the technology stack.
• A solid sense of ownership, reliability, and follow-through on committed work.

Nice-to-have experience

• Exposure to mobile development such as React Native or Flutter.
• Some familiarity with AWS, or a willingness to learn it.
• Side projects or a portfolio that show a genuine habit of building things.

Work setup

This is a remote-first role for candidates based in Europe. You must be located within CET ±3 hours.

Compensation and benefits

The role offers a competitive salary along with equity/eVSOPS. Additional perks and benefits are available through the company’s People Playbook.

About Cello

Cello is focused on helping digital businesses acquire, retain, and monetize customers at scale by turning word-of-mouth into a measurable growth engine. Its referral platform enables users and affiliates to share and discover software products in just a few clicks, reshaping how companies sell and market their products. Customers include category leaders such as Typeform, Miro, and Veed.