Senior Full-Stack Engineer (Python/Serverless + React) - B2B, full-time · Poland or Remote (Poland)

Perelyn GmbH; Remote; PLN 240,000 - 320,000; Full time

Job summary

A leading AI development firm in Poland is seeking a Senior Full-Stack Engineer to design and implement impactful products using AI technologies. This role involves developing serverless applications and collaborating with diverse teams, all while working in a remote-first environment. Ideal candidates will have extensive experience in full-stack development, particularly with Python, React, and cloud services. Competitive compensation ranging from 30,000 to 40,000 PLN per month is offered.

Benefits

Competitive salary

Remote-first work

Regular company events

Tools for optimal performance

Qualifications

• 7+ years experience in building production-grade fullstack applications.
• 3+ years developing backends with Python (FastAPI, Flask, etc.).
• 5+ years developing frontends with React + TypeScript.
• Extensive experience with cloud providers.
• Strong database skills with relational and NoSQL databases.

Responsibilities

• Design and implement serverless Python services and REST APIs.
• Set up IaC, CI/CD pipelines, and ensure reliability.
• Integrate LLM providers and automate with AI coding tools.
• Collaborate closely with product, design, and ML teams.

Skills

Fullstack application development

Backend development with Python

Frontend development with React + TypeScript

Database skills (relational & NoSQL)

Fluent English communication

Tools

AWS

Docker

Kubernetes

Job description

Your mission

At Perelyn, we don’t just talk about AI. We make it real. We help ambitious companies turn cutting-edge research into production-grade software that scales. As a Senior (AI) Full-Stack Engineer, you’ll play a central role in building products powered by large language models (LLMs), serverless backends, and modern frontends that teams genuinely love to use.
You’ll work hands-on across the stack, move fast with modern tooling, and shape how AI gets integrated into real-world applications. Along the way, you’ll collaborate closely with product, design, and ML experts and mentor the next generation of engineers.

In practice, this means you will:

• Build impactful products: Design and implement serverless Python services, clean REST APIs, and fast React + TypeScript UIs
• Operate what you build: Set up IaC, CI/CD pipelines, metrics, tracing, and SLOs to ensure reliability
• Make AI practical: Integrate LLM providers, retrieval-augmented generation (RAG), Agentic AI workflows and automate the boring parts with AI coding tools (like Claude Code)
• Collaborate & mentor: Partner with product, design, and ML to scope experiments, run lean iterations, and support mid-level engineers with thoughtful code reviews and guidance

We’re looking for aSenior Fullstack Engineer who combines strong technical depth with curiosity for how AI changes the way we build software.

Your profile

Basic Qualifications:

• 7+ years building production-grade fullstack applications
• 3+ yearsexperience developingbackends with Python (FastAPI, Flask, or similar)
• 5+ years experience developingfrontendswith React + TypeScript
• Extensive experience with knowncloud providers (e.g. AWS, Azure)
• Strong database skills with relational databases (e.g. PostgreSQL, MS SQL Servier, MySQL) and NoSQL databases (e.g. MongoDB, AWS DynamoDB, Azure CosmosDB)
• Skilled in writing clean, tested, and maintainable code; strong peer code review experience
• Fluent English communication (C1+); Polish or German is a plus

Preferred Qualifications:

• Cloud-native mindset: IaC (e.g. Terraform, CDK, Bicep), CI/CD pipelines, containerization (Docker), orchestration (Kubernetes)
• Observability: Metrics, tracing, logging, and proactive incident response
• Security awareness: OIDC/SSO, secure API design, and compliance-conscious development
• AI fluency: Practical experience with LLM integrations, RAG pipelines, embeddings, or vector databases
• Frontend excellence: Accessibility best practices, performance profiling, and UX-first mindset
• Mentorship & leadership: Ability to guide mid-level engineers, give actionable feedback, and set technical direction
• Adaptability: Comfortable experimenting with new frameworks, languages, and tools as the ecosystem evolves
• Product thinking: Able to weigh technical trade-offs, economic impact, and user needs when making decisions

Why us?

Tired of choosing between cutting‑edge AI research and real‑world product impact? With Perelyn, you don’t have to: we are an engineering‑first start-up building developer tooling that blends LLM magic with robust software craft. Perelyn is a growing AI powerhouse in Europe serving customers like Zeiss, Rewe, Roche, Deutsche Bahn and E.ON. Our current crew includes PhDs in machine learning, ex-tech-lead founders and a Rubic's Cube European Champion!

• Compensation: 30 000 – 40 000 PLN + VAT (B2B) per month or equivalent (UoP)
• Remote-first: we operate primarily remotely (with occasional visit to our clients), but there are options for onsite work in Warsaw or Poznań
• Regular company events across Europe
• You'll get the toolsyou need to work at your best (e.g. Claude Code Max 20x)