CTO / Head of Engineering

Sun.Store; Warszawa; On-site; PLN 80,000 - 120,000; Full time

Benefits offered by this job

High level of ownership

Direct influence on business strategy

Opportunity to shape company architecture

Job summary

Sun.Store, based in Warsaw, is seeking a hands-on tech leader to build AI-driven solutions within its B2B marketplace for solar energy components. This role emphasizes high ownership and collaboration with business teams, making impactful decisions to scale operations.

Ideal candidates are deeply curious about AI, possess solid software engineering skills, and can lead teams effectively. The position offers a hybrid work model and attractive compensation including ESOP.

Qualifications

• Experience in startup or scaleup environment.
• Background in operational systems or AI tooling.
• Strong foundational skills in software engineering.

Responsibilities

• Build and scale agentic AI systems.
• Make product and business decisions.
• Lead engineering while being execution-focused.

Skills

AI systems scaling

Close cooperation with business teams

Software engineering fundamentals

ML / AI exposure

Leading engineering teams

Job description

About sun.store

sun.store is the biggest B2B marketplace for solar and energy storage components in Europe. We have recently been recognized by Sifted as #1 fastest-growing startup in Europe in their annual Future 50 ranking.

Launched in October 2023, we already:

• process €100m+ GMV annually
• are truly pan-European, with 90% transactions crossing borders
• serve 45,000+ B2B users
• are backed by leading VC investors

We are building toward becoming the dominant platform in the solar and storage components space, with expansion into adjacent verticals in the plans.

But the interesting part is what comes next.

We believe the next generation of B2B platforms will not just be marketplaces. They will become AI-powered operational systems deeply integrated into business workflows.

That is exactly the direction we are heading.

What we are building

We are no longer thinking only about “the platform”.

We are building a suite of internal and external tools around:

• AI agents
• operational automation
• logistics orchestration
• merchant tooling
• AI‑assisted workflows for teams and customers

We are looking for someone excited about

• scaling agentic AI systems in production
• building software in very close cooperation with business teams

This is not a “keep the servers running” CTO role. This is a high‑ownership builder role.

Current team & stack

• fully custom‑built
• primarily PHP‑based today
• including potential migration toward a more Python‑native and AI/ML‑oriented ecosystem
• We care much more about speed, architecture quality, product thinking and execution than attachment to any specific stack.

What we are looking for

• highly energetic and hands‑on
• deeply curious about AI agents and ML
• excited by scaling real businesses, not just writing code
• comfortable making product and business decisions
• capable of leading engineering while staying close to execution
• pragmatic and fast‑moving
• interested in building an AI‑native company

Ideal background

• startup / scaleup environment
• experience with marketplaces, operational systems or AI tooling
• strong software engineering fundamentals
• ML / AI exposure is a major plus
• experience managing and growing engineering teams

What you get

• very high level of ownership and autonomy
• direct influence on business strategy and product direction
• close cooperation with founders and leadership
• ability to shape the future architecture of the company
• opportunity to build one of the most ambitious AI‑native B2B platforms in the renewable energy industry

Compensation

Attractive package, with ESOP included.

Location

flexible / hybrid preferred.

If you are excited about the idea of combining AI agents, marketplaces, operational tooling and real‑world business scale - we should talk !