Senior Fullstack Engineer (AI Product)

Opportunity to join a fast-growing AI product company and help build software that is changing how US accounting firms prepare and review taxes.

This role gives you real end-to-end ownership and the opportunity to build an AI product used in a demanding, real-world domain.

You’ll work on an AI-powered tax platform designed for professional users who deal with complex decisions every day. The product is already used by hundreds of accounting firms and combines AI with workflows where accuracy, transparency and human judgement really matter.

This is not a role focused on implementing predefined tickets. You’ll move between understanding a product problem, designing the solution, building the frontend and backend, shipping it to production and learning from how users actually interact with it.

Rate: 150–180 PLN + VAT (B2B) per hour.

Location: Fully remote (Poland) 🌎 or Łódź (Poland)

Your everyday playground:

• Build and maintain fullstack features across AI-powered tax preparation, planning and review products.

• Design and implement React interfaces, TypeScript APIs and Python backend services.

• Take ownership of features from the initial problem and discovery through implementation, release and further iteration.

• Work with real usage data and customer feedback to understand what should be improved next.

• Make product and technical decisions without waiting for every detail to be defined upfront.

• Collaborate closely with engineering, AI, product and domain experts.

• Talk to customer-facing teams and use feedback from real users to shape solutions.

• Keep the codebase clean, typed and performant while moving at startup speed.

• Decide where additional polish creates value and where shipping and learning quickly is the better choice.

What are we looking for? 🕵️‍♀️

• Senior-level commercial experience (min. 5 years) building fullstack applications (React + Python).

• Strong product mindset - you focus on the user problem and outcome, not only on implementation.

• Proven ability to take ownership of a topic end to end, from an initially unclear need to a working production solution.

• Comfort making decisions with incomplete information and clarifying the scope as you go.

• A pragmatic approach to engineering: you care about quality, but know how to balance it with speed and business impact.

• Strong collaboration and communication skills - autonomy here does not mean working alone.

• Familiarity with cloud infrastructure in Google Cloud and/or Azure.

Bonus points:

• Experience in a fast-moving startup or scale-up.

• Experience taking a product or major feature from 0 to 1.

• Experience building software in a regulated or otherwise complex domain.

• Previous experience with AI/LLM-powered products.

• Experience working directly with users or using product metrics and customer feedback to decide what to build next.

Why join us? 🌟

• Real product ownership: the outcome matters more than simply closing a ticket. You’ll have significant autonomy in deciding how to reach it.

• AI with a real use case: you’ll work on a product where AI is embedded into critical professional workflows rather than added as a side feature.

• Visible user impact: what you build is used by professionals in their everyday work, and you’ll have access to feedback and usage data.

• Fast feedback loops: features are shipped quickly, validated with users and improved based on what actually happens in production.

• End-to-end responsibility: you can influence UX, backend logic, technical decisions and the direction of the feature rather than being limited to one layer of the stack.

This environment will suit you if you enjoy building, making decisions and taking responsibility for outcomes.

Sounds like a fit? Let’s talk! 🚀