11/10/2026 updated
Premium member
100 % availableSenior Python Backend & Full-Stack Developer | FastAPI, Django, React | AI Agents & Automation
Warszawa, Poland
Only remote
Bachelor's Degree in Radioelectronics EngineeringDjangoPython (Programming Language)PostgreSQLMachine LearningBackendGitLabBackend ProgrammingGitlab-ciCeleryApi Design
Python Backend Development
Extensive expertise in building production-grade backend systems using Python, Django, Django REST Framework, and FastAPI. Development of microservices, event-driven architectures, REST APIs, and Clean Architecture patterns across fintech, recruitment, and food delivery domains.
AI / LLM Integration
Hands-on experience integrating OpenAI APIs and OpenAI-compatible models into Python services for structured extraction, classification, summarization, semantic search, and workflow automation. Work with embeddings, RAG, pgvector, Ollama, prompt design, and agentic workflow orchestration using LangGraph.
Cloud & DevOps Engineering
Proficiency in deploying and operating scalable backend systems on AWS (EC2, S3, Lambda, IoT Core) using Docker, Kubernetes, Argo CD, and GitLab CI/CD. Experience with observability tooling including Sentry, Grafana, structured logging, and performance optimization.
Database Engineering & Optimization
Deep knowledge of PostgreSQL including query optimization, indexing, caching, payload optimization, and high-performance API design for large datasets. Additional experience with Redis, Elasticsearch, MongoDB, and MySQL.
Asynchronous & Distributed Processing
Design and implementation of asynchronous processing pipelines using Celery and Redis for background scoring, data processing, batch operations, and notification workflows. Removal of blocking I/O from user-facing flows to achieve near-instant response times.
Technical Leadership & Delivery
Leadership of development teams including architecture definition, code reviews, task decomposition, release management, and stakeholder communication. End-to-end ownership from requirements and architecture through implementation, testing, CI/CD, observability, and production support.
ML Classification & Ranking
Application of ML-assisted classification and ranking workflows for CV-to-vacancy relevance matching, with asynchronous scoring, data processing, evaluation, and operational control.
Frontend Development
Contribution to frontend features using React, HTMX, TypeScript, and JavaScript, including support for AWS deployment, monitoring, and operational tasks.
Quality Assurance & Testing
Expansion of automated test coverage using Pytest, unit, integration, and behavior tests. Implementation of production observability with Sentry and Grafana, and enforcement of safe database migration practices.
Extensive expertise in building production-grade backend systems using Python, Django, Django REST Framework, and FastAPI. Development of microservices, event-driven architectures, REST APIs, and Clean Architecture patterns across fintech, recruitment, and food delivery domains.
AI / LLM Integration
Hands-on experience integrating OpenAI APIs and OpenAI-compatible models into Python services for structured extraction, classification, summarization, semantic search, and workflow automation. Work with embeddings, RAG, pgvector, Ollama, prompt design, and agentic workflow orchestration using LangGraph.
Cloud & DevOps Engineering
Proficiency in deploying and operating scalable backend systems on AWS (EC2, S3, Lambda, IoT Core) using Docker, Kubernetes, Argo CD, and GitLab CI/CD. Experience with observability tooling including Sentry, Grafana, structured logging, and performance optimization.
Database Engineering & Optimization
Deep knowledge of PostgreSQL including query optimization, indexing, caching, payload optimization, and high-performance API design for large datasets. Additional experience with Redis, Elasticsearch, MongoDB, and MySQL.
Asynchronous & Distributed Processing
Design and implementation of asynchronous processing pipelines using Celery and Redis for background scoring, data processing, batch operations, and notification workflows. Removal of blocking I/O from user-facing flows to achieve near-instant response times.
Technical Leadership & Delivery
Leadership of development teams including architecture definition, code reviews, task decomposition, release management, and stakeholder communication. End-to-end ownership from requirements and architecture through implementation, testing, CI/CD, observability, and production support.
ML Classification & Ranking
Application of ML-assisted classification and ranking workflows for CV-to-vacancy relevance matching, with asynchronous scoring, data processing, evaluation, and operational control.
Frontend Development
Contribution to frontend features using React, HTMX, TypeScript, and JavaScript, including support for AWS deployment, monitoring, and operational tasks.
Quality Assurance & Testing
Expansion of automated test coverage using Pytest, unit, integration, and behavior tests. Implementation of production observability with Sentry and Grafana, and enforcement of safe database migration practices.
Experience
Professional experience5 - 10 years
Freelancer since2020
Languages
EnglishFluentPolishBasic knowledge
Project history
Fintech platform routing retail credit applications to multiple partner banks for faster lending decisions. Developed and evolved backend workflows for high-volume financial processing using Python, Django, PostgreSQL, Celery, Redis, and AWS. Improved reliability of bank and third-party integrations through defensive validation, asynchronous processing, structured logging, and monitoring. Optimized PostgreSQL queries, indexes, and legacy modules to reduce latency. Removed blocking I/O from user-facing flows and moved notification/background work to Celery, reducing selected operations from 16-19 seconds to near-instant response. Expanded automated test coverage and production observability with Pytest, Sentry, and Grafana; contributed to Docker, Kubernetes, Argo CD, and safe database migration practices.
AI-assisted recruitment platform that matches candidate CVs with recruiter vacancies. Led architecture and delivery of FastAPI services for candidate ingestion, profile normalization, vacancy management, search, and matching. Built ML-assisted classification and ranking workflows for CV-to-vacancy relevance with asynchronous scoring and data processing through Celery and Redis. Designed PostgreSQL data models and high-performance APIs for large candidate datasets. Coordinated technical decisions, code reviews, task decomposition, and product delivery. Integrated external services and deployed scalable backend components on AWS using Docker and CI/CD.
Platform for evaluating candidates and employees through configurable assessments, scoring, and reporting. Designed scalable service architecture for assessments, scoring, result aggregation, reporting, and administration. Built concurrent APIs and Celery pipelines for background scoring, data processing, and report generation. Improved PostgreSQL performance through query analysis, indexing, caching, and payload optimization. Led the development team, defined architecture standards, reviewed code, and managed releases and delivery risks. Implemented CI/CD and AWS-based deployment; strengthened testing, logging, monitoring, and operational controls.