Anton H.
Senior Full Stack Engineer
Experience
Aug 2023 - Oct 2025
2 years 3 monthsWarsaw, Poland
Senior Full Stack Engineer
eConsulting
- Built a GenAI platform using LLMs, RAG, LangChain, and vector search, helping teams finish work 44% faster.
- Created high-speed AI APIs with FastAPI, Redis, and AWS Lambda that handled 35K+ requests per minute without downtime.
- Developed an AI search tool using embeddings and Pinecone that reduced manual research work by 60%.
- Built reliable prompt-testing tools that lowered AI error cases by 32%.
- Delivered full-stack AI dashboards with Next.js and Tailwind for tracking model results, latency, and token usage.
- Built Python microservices that allowed healthcare and finance clients to import data 3× faster.
- Developed Next.js dashboards that let users review AI outputs, compare model responses, and track improvement scores over time.
- Built Python data pipelines that cleaned, validated, and indexed customer data into Pinecone for faster and more accurate AI search.
Apr 2022 - Jun 2023
1 year 3 monthsTallinn, Estonia
Full Stack Engineer
DevLab Ltd
- Built large backend services with Node.js, NestJS, PostgreSQL, and Redis to support 65M+ logistics events each month.
- Created prediction tools with Python and FastAPI that helped reduce late deliveries by 18%.
- Developed React dashboards that helped operations teams track shipments and solve issues faster.
- Improved system reliability using AWS and Kubernetes to reach 99.98% uptime.
- Optimized pricing and routing APIs, cutting average response time from 210ms to 92ms.
- Set up CI/CD pipelines that supported daily deployments across many microservices.
- Added Redis caching to reduce repeated work and cut compute costs by 28%.
- Built scripts to detect data problems early, catching errors 40% sooner.
- Improved ETL pipelines with the data team, doubling the speed without extra servers.
Feb 2020 - Mar 2022
2 years 2 monthsMunich, Germany
Frontend Engineer
Intelligenz IT
- Built backend services with Node.js and NestJS that handled 10M+ health-record events per day.
- improved patient-risk visualization tools so care teams could review reports 55% faster.
- Rebuilt old UI code into clean component libraries, reducing build time for new features by 50%.
- Increased test coverage to 92% using Jest and Cypress.
- Added real-time features with WebSockets and Redis to help care teams coordinate faster.
- Worked with data science to display ML predictions clearly for clinical users.
- Improved frontend security, reducing vulnerability issues by 70%.
Aug 2015 - Oct 2019
4 years 3 monthsBiałystok, Poland
Frontend Developer
Softwarehut Ltd
- Built user-friendly financial dashboards using React and Bootstrap with 99.9% uptime.
- Improved payment UI flows, reducing abandoned transactions by 23%.
- Created reusable UI components that cut duplicate work by 40% across teams.
- Built analytics dashboards in Next.js to help teams monitor fraud activity.
- Improved data consistency by working closely with backend teams using Node.js and Express.
- Reduced frontend bundle size by 31%, making pages load much faster.
- Added Cypress integration tests, lowering production bugs by 35%.
- Built smooth onboarding flows that increased new-user activation by 18%.
Summary
Experienced and innovative Senior Full Stack Engineer with 10 years of experience in designing, building, scaling, and optimizing enterprise-level applications across e-commerce, healthcare, fintech, and logistics. Strong ability to design system architecture, build modern web applications and cloud-based systems and integrate AI into real-world products. Skilled in GenAI engineering, LLM integrations, RAG pipelines, vector search architectures, and automation. Recognized for solving complex technical problems, improving system performance, writing clean, maintainable code.
Languages
English
AdvancedPolish
AdvancedGerman
ElementaryEstonian
ElementaryEducation
Apr 2011 - Mar 2015
NUS - National University of Singapore
Bachelor's degree · Computer Science · Singapore
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