Senior Fullstack Engineer (Python+React)

Bonapolia; Warszawa; On-site; PLN 250,000 - 350,000; Full time

Job summary

Bonapolia is seeking a Senior GenAI Engineer to join a global internal team focused on GenAI initiatives. You will develop Python-based applications, deploy on AWS Bedrock, and design scalable APIs with a strong emphasis on data processing using PostgreSQL, Pandas, and OpenSearch.

The role requires cross-functional collaboration across regions and a hands-on, proof-of-concept delivery mindset. The ideal candidate has senior-level experience with React/Next.js frontends, LangGraph, LangChain, and

Qualifications

• Experience with Python and FastAPI in production environments.
• Hands-on GenAI and agentic development using LangGraph and LangChain.
• Experience with managed cloud GenAI services (AWS Bedrock/AgentCore or similar).
• Strong PostgreSQL and relational DB development experience.
• Hands-on with Pandas and Excel for data processing.
• Frontend experience with Next.js and React.
• Experience using AI-assisted dev tools (Cursor, Claude Code, Codex).
• Experience designing scalable APIs and backend services.

Responsibilities

• Develop, test, and maintain Python-based applications and services.
• Deploy and configure apps in AWS environments.
• Manage infrastructure using IaC while considering performance and cost.
• Work with PostgreSQL (pg_vector) or OpenSearch/Elasticsearch for vector data and RAG use cases.
• Design and implement GenAI agents using AWS Bedrock.
• Evaluate GenAI frameworks vs direct API integrations for use cases.
• Explore multi-agent solutions with AutoGen where appropriate.
• Investigate and resolve issues, optimize performance and reliability.
• Collaborate with stakeholders across global regions and drive innovation.

Skills

Python

FastAPI

GenAI

LangGraph

LangChain

AWS Bedrock

PostgreSQL

Pandas

Excel

Next.js

React

OpenSearch/Elasticsearch

AI-assisted tools

API design

Multi-agent systems

Tools

Next.js

React

PostgreSQL

OpenSearch/Elasticsearch

AWS Bedrock

Terraform

Docker

Job description

Tech Level: Senior

Language Proficiency: Upper-Intermediate

Employment type: Full time

Candidate Location: Poland

Working Time Zone: CET

Start: ASAP

Planned Work Duration: 12 months

Customer Description:

Our client is a large international enterprise operating across multiple industries and regions.

Project Description:

You will work with a specialized internal business domain team focused on internal GenAI initiatives.

Soft Skills:

• Ability to manage multiple tasks and priorities effectively in parallel
• Strong critical thinking skills
• Proactive approach to clarifying requirements
• Comfortable working in a proof-of-concept-oriented delivery environment
• Excellent communication skills

Hard Skills / Must Have:

• Experience with Python and FastAPI in production environments
• Practical experience with GenAI and agentic application development, with LangGraph as the primary framework and hands-on knowledge of LangChain
• Experience with managed cloud-based GenAI services such as AWS Bedrock / AgentCore or comparable solutions
• Strong experience with PostgreSQL and relational database development
• Hands-on experience with Pandas and Excel-based data processing
• Frontend development experience with Next.js and React
• Experience using AI-assisted development tools such as Cursor, Claude Code, or Codex
• Experience designing and developing scalable APIs and backend services

Hard Skills / Nice to Have:

• Experience with MCP and FastMCP
• Experience with web scraping and external data ingestion
• Experience with Docker, cloud-native architectures, and serverless technologies
• Experience with Terraform and cloud infrastructure troubleshooting

Responsibilities:

• Develop, test, debug, maintain, and continuously improve Python-based applications and services
• Deploy and configure applications and services in AWS environments
• Provision and manage infrastructure using Infrastructure as Code, while considering system performance and cloud costs
• Work with PostgreSQL using pg_vector or with search technologies such as OpenSearch or Elasticsearch to support vectorized custom data and Retrieval-Augmented Generation use cases
• Design and implement GenAI agents using AWS Bedrock and related cloud-based AI capabilities
• Evaluate open-source GenAI frameworks against direct API integrations with leading GenAI providers and select appropriate approaches for specific use cases
• Explore and implement multi-agent solutions using frameworks such as AutoGen where appropriate
• Investigate and resolve application, infrastructure, and integration issues, while optimizing system performance and reliability
• Collaborate with stakeholders and technical teams across multiple global regions and contribute to innovation within the broader engineering organization

Technology Stack:

Python, React, Next.js, FastAPI, LangGraph, LangChain, AWS Bedrock, PostgreSQL, ElasticSearch

Interview stages:

• English check (15 minutes)
• Internal technical interview (1-1,5 hour)
• Client interview (1 hour)

Additional notes:

The candidate must be employed in our company at 0.125FTE under UoP (employment contract). Payment terms — up to 60 days. Work will be performed using client-provided equipment.