Growth Engineer / GTM Engineer

Traffit; Warszawa; Hybrid; PLN 180,000 - 300,000; Full time

Job summary

sun.store, a Europe-wide B2B marketplace for solar equipment, seeks a Growth/GTM Engineer. You own the entire customer funnel from first ad click to repeat orders, building campaigns, flows and dashboards using AI and automation.

You’ll work directly with leadership, product and the marketplace team. The role is hands-on, full-funnel, and AI-driven, with a hybrid two-days-a-week in Warsaw.

Qualifications

• 3+ years in growth, performance marketing, marketing ops or GTM engineering, ideally at a marketplace, e-commerce or B2B platform.
• You can show a track record of moving acquisition, activation, conversion or retention with measurable before/after results.
• Hands-on Google Ads and Meta Ads experience in multi-country accounts, scaling acquisition while keeping CAC/payback on target.
• Lifecycle experience: onboarding, retention and reactivation flows in Customer.io or a similar tool.
• You write SQL and work in Mixpanel or a similar product analytics tool.
• You set up tracking: GTM, GA4, server-side tagging, conversions APIs and offline conversions.
• Experience building GTM systems: enrichment, outbound workflows, API integrations, webhooks and scripts.
• Agentic coding: you build scripts and internal tools rather than writing specs for others.
• Business-first mindset: you understand LTV, margin and payback, and prioritize high-impact work.
• English C1 or above; German/Dutch/French is a plus.

Responsibilities

• Own the full growth funnel from ad click to repeat order, running campaigns, flows, dashboards and automations.
• Acquire buyers and suppliers across Europe, setting budgets by CAC and payback and scaling what works.
• Design experiments to fix drop-offs between sign-up and first transaction and ship within the week.
• Build onboarding, activation and retention flows in Customer.io across channels.
• Create signal-based outbound outreach for suppliers, distributors and partners with AI agents.
• Develop AI-native distribution channels and integrate with major AI labs ecosystems.
• Own tracking, data and analytics: GA4, server-side, conversions APIs and Mixpanel cohorts.
• Maintain a single, rigorous testing process and document learnings as company knowledge.
• Code tools and automation to reduce repetitive work and speed up campaigns.

Skills

Growth marketing

Performance marketing

Marketing ops

GTM engineering

SQL

Customer.io

Mixpanel

BigQuery

GA4

Campaign automation

Tools

Google Ads

Meta Ads

LinkedIn Ads

Microsoft Ads

PostHog

Mixpanel

BigQuery

Looker Studio

Customer.io

SQL

GTM

GA4

server-side tagging

APIs / webhooks

n8n

Job description

sun.store is Europe's B2B marketplace for solar and energy-storage equipment. Installers, distributors and wholesalers across the EU use it to buy and sell PV modules, inverters, batteries and more.

Theshort version: one engineer who owns the growth numbers. You find where buyers and suppliers drop off, from the first ad click to the tenth order, design the fix, build it with AI and automation, and ship it the same week.

About the role

As Growth / GTM Engineer you own the whole customer funnel, from the first ad click to the tenth repeat order. You run acquisition, conversion, lifecycle, partneroutreach and analytics yourself, in one connected system.

We are not hiring a marketing team to do this. We are hiring one builder who uses AI, automation and a modern data stack to do the work of a team. You ship campaigns, flows, dashboards and automations every week, and you measure them against business results: new active buyers and suppliers, transactions, GMV, CAC and payback.

You work directly with leadership, product, sales and the marketplace team. Hybrid: two days a week in our Warsaw city-centre office.

What you'll own

Paid acquisition across Europe. Run Google Ads and Meta Ads hands-on in every EU market and language we sell in: Search, Performance Max, Demand Gen, YouTube, prospecting and retargeting. Acquire both sides of the marketplace, buyers and suppliers. Set budgets by CAC and payback, scale what works and cut what doesn't.

Activation and conversion. Find where buyers and suppliers stall between sign-up and their first transaction. Design the experiment that fixes it, build it and ship it within the week, working with product when the fix lives in the app.

Lifecycle and retention in Customer.io. Build onboarding, activation, first-order, repeat-purchase and reactivation flows across email, in-app and other channels. Turn first-time buyers into regular customers and keep suppliers active.

Signal-based outreach. Build outbound systems for suppliers, distributors and partners: catch buying and selling signals, enrich and qualify accounts with AI agents, run personalised sequences at scale and hand warm leads to sales.

AI-native distribution. Put sun.store where professionals already work with AI: apps and connectors in the ecosystems of the big AI labs (ChatGPT, Claude, Gemini), plus visibility in AI search answers. Treat it as a new acquisition channel, with its own funnel and numbers.

Tracking, data and analytics. Own GTM, GA4, server-side tracking, Meta Conversions API, enhanced conversions and Consent Mode v2. Instrument everything you ship in Mixpanel so every change has a number behind it. Send transaction data back to ad platforms, model data in BigQuery and run cohort analysis.

Experimentation. One testing process across the funnel: a clear hypothesis, shipped behind a flag, a result you act on. Document what you learn so it becomes company knowledge.

AI and automation. Use AI agents, MCP servers and workflow automation everywhere it saves time: campaign builds, creative variants, translations, reporting, enrichment, lifecycle content and analysis. If you do something twice, you automate it.

Your stack

• You work on a modern stack and can add the tools you need to move faster. Tools marked "or similar" are examples, not requirements
• Paid acquisition: Google Ads, Meta Ads; LinkedIn Ads and Microsoft Ads where they pay back
• Product analytics and data:PostHog/Mixpanel, BigQuery, SQL, Looker Studio
• Retention: Customer.io, Internal CRM
• Automation: n8n, Make or similar; APIs and webhooks
• AI distribution: Apps and connectors for ChatGPT, Claude and Gemini (Apps SDK, MCP)
• AI at work: Claude, Claude Code and other coding agents; MCP servers connected to ads, analytics and lifecycle data

This role is / is not

This role is:

Hands-on. You build and run the campaigns, flows, automations and dashboards yourself.

Full-funnel. You are measured on new active customers, repeat purchases, GMV and CAC payback, not on clicks, opens or ROAS alone.

High impact. You are the growth engine of a European marketplace, with a direct line to leadership and real budget decisions.

AI-native. Automation and AI agents are how you scale your output, not an experiment on the side.

This role is not:

A people-management role. There is no team to manage at the start; you multiply yourself with tools.

A single-channel specialist role. Paid, lifecycle, outreach and analytics are all yours.

A brand or content role. Brand and content serve acquisition and retention here.

What you bring

3+ years in growth, performance marketing, marketing ops or GTM engineering, ideally at a marketplace, e-commerce or B2B platform.

A track record you can show in numbers: you have moved acquisition, activation, conversion or retention, and you can show the before and after.

Hands-on Google Ads and Meta Ads experience in multi-country accounts, scaling acquisition while keeping CAC and payback on target.

Lifecycle experience: you have built onboarding, retention and reactivation flows in Customer.io or a similar tool.

You think in metrics. You can define an activated buyer from the data, take a metric apart and say which funnel stage is leaking and why. You write SQL and work in Mixpanel or a similar product analytics tool.

Tracking you set up yourself: GTM, GA4, server-side tagging, conversions APIs and offline conversion imports, without waiting for developers.

Experience building GTM systems: enrichment and qualification workflows, signal-based outbound, integrations through APIs, webhooks and scripts, with Clay or similar tools.

Agentic coding is part of your daily workflow. You build scripts, integrations and small internal tools yourself instead of writing specs for others.

A business-first mindset. You understand LTV, contribution margin and payback, and pick the work with the biggest impact.

English C1 or above. German, Dutch or French is a plus.

Nice to have

Experience with a two-sided marketplace and growing both demand and supply.

Background in solar, energy, construction or industrial B2B.

Launching paid and lifecycle programmes in new European markets.

Incrementality testing: geo holdouts and conversion lift studies.

Experience at a scale-up during fast growth.

What we offer

Ownership of the full growth funnel at a European marketplace, with direct impact on company results.

A modern stack and the freedom to add the AI and automation tools you need.

A disruptive startup in the fast-growing photovoltaics industry, backed by an industry parent company.

Room to grow: as the business scales, the role can grow into leading a growth team.

10 paid workation days per year, under the applicable contractual arrangements.

Hybrid work: two days per week in our Warsaw city-centre office, with the rest of the week remote.

Private medical care through Lux Med.

How we work

Small team, high trust, low process. Owners make decisions, not committees.

You ship in your first week and talk to customers in your first weeks.

No layers: you work directly with leadership, product and sales.

We build, measure, keep what works and iterate. Every win shows up in the numbers the next week, and everyone knows whose work it was.

Recruitment process

Interview with the hiring manager (60 min).

Practical task (max. 4 hours): a 90-day acquisition-to-retention plan for one market, plus one working build, such as an automated outreach flow, a lifecycle flow or a reporting automation. Show us how you used AI to make it.

Final interview with leadership, followed by a reference check.

Offer.