Antonio Simunic - Senior AI/Fullstack Engineer

Q: Where is Antonio based?

Antonio is based in Zadar, Croatia .

Q: What languages does Antonio speak?

Antonio speaks the following languages: English (Advanced), Croatian (Elementary) .

Q: How many years of experience does Antonio have?

Antonio has at least 7 years of experience. During this time, Antonio has worked in at least 3 different roles and for 3 different companies . The average length of individual experience is 2 years and 4 months . Note that Antonio may not have shared all experience and actually has more experience.

Q: What is Antonio's latest experience?

Antonio's most recent position is Senior AI/Fullstack Engineer at Siemens .

Q: What companies has Antonio worked for in recent years?

In recent years, Antonio has worked for Siemens and Stripe .

Q: Which industries is Antonio most experienced in?

Antonio is most experienced in industries like Information Technology , Banking and Finance , and Professional Services . Antonio also has some experience in Manufacturing .

Q: Which business areas is Antonio most experienced in?

Antonio is most experienced in business areas like Information Technology , Product Development , and Research and Development .

Q: Which industries has Antonio worked in recently?

Antonio has recently worked in industries like Banking and Finance , Information Technology , and Manufacturing .

Q: Which business areas has Antonio worked in recently?

Antonio has recently worked in business areas like Information Technology , Product Development , and Research and Development .

Recommended expert

Zadar, Croatia

Check rate

Experience

Oct 2025 - Mar 2026

6 months

Senior AI/Fullstack Engineer

Siemens

Architected and delivered an intelligent knowledge platform enabling engineers to search, analyze, and retrieve information from millions of technical documents and operational manuals using natural language
Built Retrieval-Augmented Generation (RAG) pipelines using vector databases, embeddings, semantic search, and LLMs, improving knowledge retrieval efficiency by ~40%
Developed scalable microservices and backend systems using Java Spring Boot, Python, and C# .NET, deployed on Azure cloud infrastructure, supporting high-volume operational data processing
Designed and deployed cloud-native event-driven systems on Azure Kubernetes Service (AKS) and Docker, improving system scalability and reliability
Designed modern web dashboards using React, Angular, and TypeScript for real-time visibility into equipment performance and analytics
Implemented AI-powered document summarization and workflow automation, reducing manual reporting effort by ~35%
Built CI/CD pipelines using Azure DevOps and Git-based workflows, reducing deployment cycle time by ~40%
Collaborated with cross-functional teams to deliver large-scale digital transformation initiatives

Feb 2021 - Aug 2025

4 years 7 months

Senior Fullstack Engineer

Stripe

Developed scalable financial systems and distributed services supporting payment processing, transaction analytics, and merchant operations
Built customer-facing applications and internal platforms using React and TypeScript, improving workflow efficiency
Designed and implemented microservices using Java, Python, and C# .NET deployed on AWS cloud infrastructure, supporting high availability and fault tolerance
Built and managed cloud-native services using AWS (EC2, S3, Lambda, API Gateway) with focus on scalability and cost efficiency
Implemented machine learning solutions for fraud detection and risk scoring, improving model accuracy
Developed feature engineering and ML pipelines using Python and TensorFlow, reducing model iteration time by ~30%
Built AI-powered internal tools using LLMs for payment investigation and support automation, reducing manual operational effort
Implemented semantic search and RAG systems using embeddings and vector databases, improving knowledge retrieval speed by ~35–45%
Designed event-driven and asynchronous architectures using cloud messaging and caching systems, improving system throughput
Optimized APIs and databases, reducing latency by ~25–35%
Built CI/CD pipelines and observability systems using AWS-native tools, improving deployment speed and incident response time

Nov 2018 - Nov 2020

2 years 1 month

Software Consultant

Capgemini

Developed and maintained enterprise applications for global clients across various industries
Built responsive web applications using Angular, JavaScript, HTML, CSS, and TypeScript
Developed backend services and business logic using Java (Spring Boot) and C#
Worked closely with business analysts and stakeholders to translate requirements into technical solutions
Created REST APIs and integrated third-party services to support business applications
Participated in Agile ceremonies including sprint planning, retrospectives, and daily standups
Wrote unit tests and performed code reviews to maintain code quality and reliability
Assisted with application deployments, production support, and issue resolution
Contributed to database design, query optimization, and performance improvements

Industry Experience

See where this freelancer has spent most of their professional time.

Experienced in Information Technology, Banking and Finance, Professional Services, and Manufacturing.

Information Technology

Banking and Finance

Professional Services

Manufacturing

Business Area Experience

See which departments and functions this freelancer has contributed to most.

Experienced in Information Technology, Product Development, and Research and Development.

Information Technology

Product Development

Research and Development

Summary

Senior Full Stack /AI Engineer with 8+ years of experience building scalable web applications, APIs, and cloud-based systems across fintech and enterprise domains. Experienced in Machine Learning since 2022 and Generative AI since 2024, building intelligent applications using LLMs, RAG, and data-driven automation to improve business processes.

Skills

Python
C#
Javascript
Typescript
Java
Sql
Bash
React.Js
Angular
Redux
Next.Js
React Native
Html5
Css3
Sass
Tailwind Css
Micro-Frontend Architecture
Node.Js (Express, Nestjs)
Ruby On Rails
Fastapi
Flask
Restful Apis
Graphql
Grpc
Distributed Systems
Event-Driven Architecture
Microsoft Azure
Aws
Gcp
Docker
Kubernetes
Terraform
Ci/Cd (Azure Devops, Github Actions)
Openai Api
Hugging Face Transformers
Retrieval-Augmented Generation (Rag)
Ai Agents
Nlp Systems
Prompt Engineering
Mlops
Azure Ai Search
Postgresql
Mongodb
Redis
Sql Server
Cosmos Db
Elasticsearch
Opentelemetry
Prometheus
Grafana
Logging & Monitoring
Performance Optimization
Distributed Tracing

Languages

English

Advanced

Croatian

Elementary

Education

Sep 2016 - Sep 2018

University of Zagreb

Master’s in Computer Science · Computer Science · Zagreb, Croatia

Statistics

Experience

Total positions 3

Experience in Information Technology 6.5 y

Avg length 2 y 4 m

Longest experience 4 y 6 m

Expertise

Recent roles Senior AI/Fullstack Engineer, Senior Fullstack Engineer, Software Consultant

Main industries Information Technology, Banking and Finance, Professional Services

Main business areas Information Technology, Product Development, Research and Development

Qualifications

Highest degree Master

Profile

Created

June 2026

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Frequently asked questions

Have questions? Find more information here.

Where is Antonio based?

Antonio is based in Zadar, Croatia.

What languages does Antonio speak?

Antonio speaks the following languages: English (Advanced), Croatian (Elementary).

How many years of experience does Antonio have?

Antonio has at least 7 years of experience. During this time, Antonio has worked in at least 3 different roles and for 3 different companies. The average length of individual experience is 2 years and 4 months. Note that Antonio may not have shared all experience and actually has more experience.

What roles would Antonio be best suited for?

Based on recent experience, Antonio would be well-suited for roles such as: Senior AI/Fullstack Engineer, Senior Fullstack Engineer, Software Consultant.

What is Antonio's latest experience?

Antonio's most recent position is Senior AI/Fullstack Engineer at Siemens.

What companies has Antonio worked for in recent years?

In recent years, Antonio has worked for Siemens and Stripe.

Which industries is Antonio most experienced in?

Antonio is most experienced in industries like Information Technology, Banking and Finance, and Professional Services. Antonio also has some experience in Manufacturing.

Which business areas is Antonio most experienced in?

Antonio is most experienced in business areas like Information Technology, Product Development, and Research and Development.

Which industries has Antonio worked in recently?

Antonio has recently worked in industries like Banking and Finance, Information Technology, and Manufacturing.

Which business areas has Antonio worked in recently?

Antonio has recently worked in business areas like Information Technology, Product Development, and Research and Development.

What is Antonio's education?

Antonio holds a Master in Computer Science from University of Zagreb.

What is the availability of Antonio?

Antonio is immediately available full-time for suitable projects.

What is the rate of Antonio?

Antonio's rate depends on the specific project requirements. Please use the Meet button on the profile to schedule a meeting and discuss the details.