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Senior AI Engineer with a strong foundation in computer science and a track record of building high-impact, production-grade systems. Experienced across AI and backend engineering, with recent contract roles at DeepL and Revolut, delivering scalable, reliable solutions in fast-paced environments. Combines deep technical expertise with practical product thinking, backed by a Master’s in Computer Science from the University of Belgrade.…Senior AI Engineer with a strong foundation in computer science and a track record of building high-impact, production-grade systems. Experienced across AI and backend engineering, with recent contract roles at DeepL and Revolut, delivering scalable, reliable solutions in fast-paced environments. Combines deep technical expertise with practical product thinking, backed by a Master’s in Computer Science from the University of Belgrade.

Stefan Berat

AI Engineer, Full Stack Developer, Back-End Developer

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Senior AI Engineer with a strong foundation in computer science and a track record of building high-impact, production-grade systems. Experienced across AI and backend engineering, with recent contract roles at DeepL and Revolut, delivering scalable, reliable solutions in fast-paced environments. Combines deep technical expertise with practical product thinking, backed by a Master’s in Computer Science from the University of Belgrade.…Senior AI Engineer with a strong foundation in computer science and a track record of building high-impact, production-grade systems. Experienced across AI and backend engineering, with recent contract roles at DeepL and Revolut, delivering scalable, reliable solutions in fast-paced environments. Combines deep technical expertise with practical product thinking, backed by a Master’s in Computer Science from the University of Belgrade.

Available to hire

Senior AI Engineer with a strong foundation in computer science and a track record of building high-impact, production-grade systems. Experienced across AI and backend engineering, with recent contract roles at DeepL and Revolut, delivering scalable, reliable solutions in fast-paced environments. Combines deep technical expertise with practical product thinking, backed by a Master’s in Computer Science from the University of Belgrade.

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Language

Serbian

Fluent

English

Advanced

Work Experience

Senior AI Engineer at DeepL

June 1, 2023 - Present

- Designed and shipped production RAG pipelines using Python, FastAPI, and Azure Functions, enabling secure retrieval and grounding of enterprise tax knowledge for 10k+ users. - Integrated LangChain and LangGraph to orchestrate multi-agent LLM workflows, supporting streaming updates, tool/function calling, and human-in-the-loop steps. - Built robust RESTful and GraphQL APIs for AI-powered assistants, ensuring <200ms latency and 99.99% uptime across internal platforms.

Software Engineer at Revolut

April 1, 2022 - May 1, 2023

- Integrated event-driven workflows using Kafka and AWS Lambda, enabling real-time transaction processing and notifications. - Optimized SQL database queries and schema migrations, reducing latency by 25% for high-throughput financial operations. - Built observability dashboards with Prometheus and Grafana, proactively identifying and resolving performance bottlenecks.

Backend Developer at HTEC Group

September 3, 2018 - March 1, 2022

- Built and maintained RESTful APIs in Python (Flask, Django) and Java, supporting B2B SaaS applications for 50+ enterprise clients. - Developed data ingestion pipelines with Spark and Databricks, processing 10TB+ of structured/unstructured data monthly.

Education

Bachelor of Computer Science at University of Belgrade

September 1, 2014 - September 3, 2018

- Focus: Software Engineering, Algorithms, Databases - Built distributed microservice architecture as final-year project - Competitive programming club member

Master of Computer Science at University of Belgrade

September 3, 2018 - September 7, 2020

- Focus: Machine Learning, NLP, Distributed Systems - Thesis: Efficient Retrieval-Augmented Generation for Enterprise Knowledge Systems - Research assistant in Applied AI Lab