Senior Fullstack Engineer (LLMs & AI Agents)

Tappz GmbH; Warszawa; Hybrid; PLN 120,000 - 180,000; Full time

Benefits offered by this job

Remote-friendly setup

Job summary

Tappz GmbH in Warsaw is building AI-native applications powered by large language models. We’re looking for an engineer focused on AI systems and agent development with a mindset of ownership and speed to ship real AI products.

You will design backend systems powered by LLMs, develop agent workflows, build RAG pipelines, manage prompts and context, optimize performance and costs, and ship AI features into production.

Qualifications

• Experience with LLMs and AI APIs
• Experience building AI agents or multi-step workflows
• Strong backend and frontend engineering skills
• Knowledge of vector databases (e.g., Pinecone, Weaviate) and RAG pipelines
• Experience with prompt engineering and system design
• Production deployment experience

Responsibilities

• Design and build backend systems powered by LLMs
• Develop agent workflows and tool integrations
• Build RAG pipelines with vector search
• Handle prompt orchestration and context management
• Optimize performance, latency, and cost
• Ship AI features into production products

Skills

LLMs & AI APIs

AI agents

Prompt engineering

System design

Production deployment

Ownership mindset

Performance optimization

Cost optimization

Tools

Node.js

Next.js

TypeScript

Python

Nest.js

GCP

Pinecone/Weaviate

Job description

Location: Warsaw

Tappz is building AI-native applications powered by large language models. We’re moving fast in a highly competitive space and need an engineer who is fully focused on AI systems and agent development.

We’re looking for someone who enjoys high ownership, working hard, and shipping real AI products.

Tasks

• Design and build backend systems powered by LLMs
• Develop agent workflows and tool integrations
• Build RAG pipelines with vector search
• Handle prompt orchestration and context management
• Optimize performance, latency, and cost
• Ship AI features into production products

Requirements

• Strong backend and frontend engineering (Node.js, Next.js, Typescript, Python, Nest.js, GCP)
• Deep experience working with LLMs and AI APIs
• Experience building AI agents or multi-step workflows
• Vector DB experience (Pinecone/Weaviate/etc.)
• RAG implementation experience
• Prompt engineering and system design
• Production deployment experience

Mindset we value: Ownership, speed, and the willingness to go the extra mile

Benefits

• High ownership in a fast-growing AI startup, remote-friendly setup, and the chance to build agent systems in production.