/Mid Fullstack Engineer

Mid Fullstack Engineer

Kraków, PLplvia direct
// Job Type
Full Time
// Salary
PLN 14,000 - 20,000/month
// Salary Range
14,000–20,000 PLN / month
// Posted
4 months ago

About the Role

We’re looking for a Mid Full Stack Engineer who builds end-to-end features across our Next.js frontend and Node.js backend — and uses AI tools daily to ship faster. You’ll work in a modern TypeScript monorepo powering an AI-enabled platform, contributing to both the product and the AI agent infrastructure behind it. This isn’t an ML research role — it’s a hands-on engineering role where AI is part of your daily workflow and the product you’re building.

Responsibilities:

  • Build and ship full-stack features end-to-end in a TypeScript/Next.js/React monorepo
  • Develop and maintain backend services using Node.js, Hono, and Express
  • Work with Prisma ORM and PostgreSQL (with pgvector) and MongoDB via Mongoose
  • Contribute to AI agent workflows built on Mastra and the Vercel AI SDK
  • Use AI coding tools (Cursor, Claude, Copilot) daily to accelerate development
  • Deploy and maintain services on GCP Cloud Run with Terraform
  • Improve observability using Datadog APM/RUM and OpenTelemetry
  • Collaborate with product, design, and engineering in an agile environment
  • Write clean, testable code and participate in code reviews

Required Qualifications:

Engineering (2–4 years commercial experience):

  • Strong TypeScript and JavaScript fundamentals
  • Hands-on experience with React and Next.js (App Router)
  • Backend experience with Node.js (Express, Hono, or similar)
  • Working knowledge of relational databases (PostgreSQL) and an ORM (Prisma preferred)
  • Familiarity with REST APIs and basic cloud infrastructure concepts
  • Understanding of Git workflows, CI/CD pipelines, and code quality tools (ESLint, Prettier)
  • Comfortable working in a monorepo (Turborepo experience is a plus)

AI Mindset & Tooling:

  • Regularly uses AI-assisted development tools (Cursor, Claude, GitHub Copilot)
  • Curious about LLM integrations and AI SDK patterns — willing to learn Mastra and Vercel AI SDK
  • Uses AI for real productivity gains, not just experimentation

Product & Collaboration:

  • Understands the “why” behind features, not just the “how”
  • Comfortable working closely with product and design stakeholders
  • Good English communication skills (written and spoken)

Nice to Have:

  • Experience with Mastra or similar AI agent frameworks
  • Familiarity with GCP (Cloud Run, Cloud SQL, Artifact Registry)
  • Terraform or other IaC experience
  • MongoDB/Mongoose experience
  • Tailwind CSS and Radix UI / shadcn component libraries
  • Experience with Clerk authentication
  • Exposure to observability stacks (Datadog, Langfuse, OpenTelemetry)
  • Familiarity with Docker and containerized deployments

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