Milan is available for hire
Hire MilanMilan Simonovic
Verified Expert in Engineering
Software Developer
Zürich, Switzerland
Toptal member since June 1, 2017
Bio
Milan is a seasoned software engineer with almost two decades of experience developing and operating web applications. He's written production code in over five programming languages and has used SQL and NoSQL databases. He also has experience working in DevOps. Milan's leadership experience is another aspect of his expertise. He has a proven track record of taking ideas and delivering them as final solutions, demonstrating his ability to lead projects from start to finish.
Portfolio
Avaloq
Terraform, Azure, Observability, Kubernetes, DevOps, Distributed Systems...
Squirro
Python, Custom Solutions, Artificial Intelligence (AI)
DVX HVAC CO
Amazon Web Services (AWS), AWS IoT, Python, MQTT, Amazon DynamoDB, AWS Lambda...
Experience
- DevOps - 15 years
- DevOps Engineer - 15 years
- Solution Architecture - 10 years
- Technical Leadership - 10 years
- Microservices Architecture - 8 years
- CTO - 7 years
- NoSQL - 7 years
- Amazon Web Services (AWS) - 5 years
Preferred Environment
Amazon Web Services (AWS), Visual Studio Code (VS Code), Git, Linux, MacOS, Serverless, TypeScript, Python, Terraform, DevOps
The most amazing...
...thing I've accomplished was leading the development of a US-based RealTech startup. We went from idea to exit in less than a year!
Work Experience
Cloud Architect/DevOps
2024 - PRESENT
Avaloq
- Helped reduce costs by over 50% by identifying underutilized resources, implementing right-sizing strategies, and scheduling compute resource shutdowns during idle periods.
- Automated the entire banking platform application infrastructure in Azure using Terraform.
- Closed all automation gaps, which reduced the time needed to spin a new environment by 60 percent.
Technologies: Terraform, Azure, Observability, Kubernetes, DevOps, Distributed Systems, Anthropic, Linux
Senior Solutions Engineer
2023 - 2024
Squirro
- Improved document handling efficiency and reduced errors for a large foreign bank by implementing a document status tracking system.
- Contributed to two successful sales to enterprise clients by making custom-tailored demos.
- Identified a lack of observability in our custom software, which required manual log reviews to troubleshoot issues. I proposed and implemented a logging and monitoring solution, significantly improving issue detection and response times.
Technologies: Python, Custom Solutions, Artificial Intelligence (AI)
AWS IoT Solution Architect
2023 - 2024
DVX HVAC CO
- Designed and implemented a fleet management solution that includes device registration and authentication using X.509, just-in-time provisioning, and MQTT message logging using Kinesis.
- Developed and executed over-the-air updates where new firmware is delivered using AWS IoT Jobs.
- Crafted and implemented device configuration management where new configuration gets published via SNS and stored in Dynamo before being delivered to devices via MQTT.
Technologies: Amazon Web Services (AWS), AWS IoT, Python, MQTT, Amazon DynamoDB, AWS Lambda, Amazon Simple Notification Service (SNS), Terraform, AWS IoT Core, Internet of Things (IoT), New Products
DevOps Engineer
2023 - 2023
BestBytes
- Handled infrastructure management with Terraform and Terragrunt.
- Performed monitoring and alerting with Prometheus and Grafana.
- Conducted incident detection, root cause analysis, and bot traffic analysis. Developed a security incident response plan.
Technologies: Kubernetes, HAProxy, Terraform, Amazon Web Services (AWS), Prometheus, Grafana, Containers, Amazon EC2, Amazon RDS, Cloudflare, Observability, Distributed Systems, AWS IoT, Linux
Lead Node.js Engineer
2022 - 2023
G-IT AG
- Worked on an escort booking platform. Completed the MVP that had started four years earlier.
- Completed cloud migration from Vultr to Amazon Web Services (AWS).
- Performed a security review and check, identified and prioritized findings, and fixed the most critical vulnerabilities.
Technologies: JavaScript, Node.js, MySQL, Amazon Web Services (AWS), Linux, AdonisJS, Jenkins, Sentry, Octopus Deploy, PHP, MariaDB, Amazon EC2, AWS Elastic Beanstalk, Laravel, Disaster Recovery Plans (DRP), Technical Architecture, Redis Cache, Amazon CloudFront CDN, WebSockets, Agile, Minimum Viable Product (MVP), Startups, New Products, AWS IoT
CTO
2022 - 2022
Alec Beglarian
- Provided technical leadership, made strategic technical decisions, drove product architecture, and aligned technical requirements with business requirements.
- Collaborated with the CEO to hire talent, including sourcing and interviewing. Assessed candidates' skills and cultural fit.
- Wore multiple hats, including DevOps and automating cloud infrastructure provisioning.
Technologies: CTO, Technical Leadership, Minimum Viable Product (MVP), AWS Cloud Architecture, Cloud Infrastructure, Solution Architecture, Cloud Computing, System Architecture, Technical Architecture, Amazon CloudFront CDN, VPN, Amazon Virtual Private Cloud (VPC), Amazon EC2, Amazon RDS, Startups, Project Management, Strategy, New Products, AWS IoT
Senior DevOps (AWS) Engineer
2022 - 2022
CTL Law
- Completed a multi-account environment setup (landing zone) bootstrapped with Control Tower and managed with Terraform and Terragrunt.
- Handled the maintenance and improvements of a serverless data processing pipeline that ingests PDFs, XML, HTML, and images, does OCR using Textract, and stores results in Elasticsearch.
- Implemented and documented a disaster recovery procedure.
Technologies: Cloud Infrastructure, Terraform, Terragrunt, CI/CD Pipelines, Serverless, AWS Lambda, Data Processing, System Architecture Design, AWS Elastic Beanstalk, Technical Leadership, DevOps Engineer, Infrastructure as Code (IaC), Amazon RDS, AWS CodePipeline, AWS CodeDeploy, Python, PostgreSQL, Amazon Web Services (AWS), Git, SQL, DevOps, Continuous Delivery (CD), SaaS, AWS Cloud Architecture, Software as a Service (SaaS), Amazon Simple Queue Service (SQS), Solution Architecture, Cloud Computing, Sentry, Load Balancers, Container Orchestration, AWS DevOps, AWS Deployment, Disaster Recovery Plans (DRP), Technical Architecture, Amazon Virtual Private Cloud (VPC), Amazon Aurora, Startups, Amazon Elastic Container Service (ECS), Redis, Amazon ElastiCache, Strategy, New Products, SOC 1, SOC 2, AWS Fargate, Observability, AWS IoT, Linux, Vanta, AWS Key Management Service (KMS)
Interim CTO
2022 - 2022
Raise
- Evaluated the entire organization, identified areas for improvement, prioritized the findings with the CEO, made a roadmap, and worked with different teams on implementation.
- Improved the security posture by implementing OWASP (The Open Web Application Security Project) measures and started rolling out a security standard across all engineering teams.
- Contributed to a project that is a work in progress, namely an application security program.
Technologies: Agile, Lean Product Development, CTO, Technical Leadership, Security, Strategy
Solutions Architect
2021 - 2022
USC ICT
- Handled the production readiness and application architecture reviews to identify weak points and prioritize the findings with the stakeholders.
- Implemented the application and infrastructure monitoring in Terragrunt and Terraform.
- Migrated a Python, Flask, and Celery app running in AWS Beanstalk to a serverless architecture to solve reliability and performance problems.
- Designed and implemented back-end services load and performance tests to identify bottlenecks.
Technologies: Amazon Web Services (AWS), Terraform, Terragrunt, Python, Node.js, GraphQL, New Relic, Load Testing, CI/CD Pipelines, Flask, Amazon Simple Queue Service (SQS), DevOps, Amazon S3 (AWS S3), Amazon EC2, Cloud Infrastructure, System Architecture Design, Amazon API Gateway, Amazon CloudWatch, NoSQL, Serverless, Technical Leadership, DevOps Engineer, Infrastructure as Code (IaC), GitHub, AWS CodePipeline, Docker, MongoDB, Git, APIs, Web Architecture, AWS Lambda, Microservices, Serverless Framework, Web Development, Continuous Delivery (CD), Solution Architecture, TypeScript, Cloud Computing, Sentry, AWS DevOps, AWS Deployment, System Architecture, Autoscaling, Technical Architecture, Agile, Containers, Audio Processing, Machine Learning Operations (MLOps), AWS IoT
Lead Engineer | CTO
2021 - 2021
Hello Equity
- Managed all technical aspects of the project, handling the overall architecture for the entire system, including a data pipeline, multiple services to power the API, analytics, and tracking to store data in a warehouse.
- Led a small team of two front-end developers and one DevOps engineer.
- Led the technical aspects of the due diligence process with the VP of technology after the MVP reached completion, two customers signed, and the startup was successfully sold.
Technologies: Amazon Web Services (AWS), APIs, Architecture, Amazon DynamoDB, AWS Lambda, Back-end, Code Architecture, Data Aggregation, Database Modeling, Data Processing, DevOps, Serverless, Node.js, Web Architecture, Team Leadership, CTO, Data Analysis, TypeScript, Data Visualization, Data Pipelines, Cloud Architecture, AWS Cloud Architecture, Solution Architecture, Web Platforms, REST, REST APIs, Leadership, Management, React, Terraform, Terragrunt, Elasticsearch, Lean Startups, Lean Product Development, Amazon EC2, Cloud Infrastructure, System Architecture Design, Amazon API Gateway, Amazon CloudWatch, NoSQL, Technical Leadership, DevOps Engineer, Infrastructure as Code (IaC), API Integration, GitHub, Minimum Viable Product (MVP), Python, Git, Microservices, Serverless Framework, Web Development, SaaS, Software as a Service (SaaS), Cloud Computing, Multiple Listing Services (MLS), AWS DevOps, AWS Deployment, System Architecture, Technical Architecture, Data Warehousing, Containers, Startups, Project Management, Data Modeling, Strategy, SOC 1, AWS IoT, Linux
Software Engineer | Tech Lead
2019 - 2021
Crowdhouse
- Developed the back end for an auctioning system that's used to attract institutional customers.
- Started introducing business analytics in the company so that we could make better-informed decisions.
- Worked on a recommendation system to improve our customer experience and improve sales.
Technologies: Salesforce API, Architecture, Serverless Architecture, Serverless Framework, Database Modeling, Web Architecture, Python, Twilio API, Software Architecture, APIs, MySQL, Node.js, AWS Lambda, REST APIs, Microservices, Microservices Architecture, Elasticsearch, Amazon Web Services (AWS), TypeScript, Serverless, Technical Leadership, Code Architecture, Team Leadership, React, Full-stack, RESTful Microservices, JavaScript, Web Application Architecture, Amazon DynamoDB, GraphQL, Amazon Simple Notification Service (SNS), Data Visualization, Continuous Delivery (CD), Cloud Architecture, AWS Cloud Architecture, Scalability, Web Scalability, Solution Architecture, Web Platforms, Salesforce, eCommerce, Segment, Segment.io, REST, Leadership, Swagger, Terraform, Amazon Simple Queue Service (SQS), Lean Startups, Lean Product Development, Amazon S3 (AWS S3), Cloud Infrastructure, System Architecture Design, Amazon API Gateway, Amazon CloudWatch, NoSQL, DevOps Engineer, Infrastructure as Code (IaC), API Integration, GitHub, Web Applications, Linux, Docker, PostgreSQL, Git, SQL, DevOps, Web Development, Design Patterns, TypeORM, Cloud Computing, Next.js, Sentry, AWS DevOps, AWS Deployment, Data Warehousing, Redis Cache, WebSockets, Agile, Containers, Minimum Viable Product (MVP), Customer Relationship Management (CRM), Startups, OpenAPI, API Gateways, AWS IoT
Scientific Programmer
2008 - 2019
University of Zürich
- Acted as the main developer for all back-end architecture and implementation and the client-side web app design and development.
- Participated in an international scientific group that was developing a standard for representing protein interaction data. This resulted in a published paper: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3246345/.
- Automated fully the entire continuous development and delivery pipeline.
- Worked as a teaching assistant for an undergraduate course in programming.
- Built and maintained an HPC cluster to run data-crunching applications.
Technologies: Architecture, Database Modeling, Web Architecture, Docker Swarm, Software Architecture, APIs, Amazon Web Services (AWS), Vue, Node.js, REST APIs, Microservices, Microservices Architecture, DevOps, Linux, Docker, Neo4j, PostgreSQL, MongoDB, Java, Python, Technical Leadership, Code Architecture, Team Leadership, Full-stack, Data Processing, Data Aggregation, RESTful Microservices, JavaScript, Web Application Architecture, Data Visualization, Data Pipelines, Continuous Delivery (CD), Express.js, Cloud Architecture, AWS Cloud Architecture, Scalability, Web Scalability, Solution Architecture, Web Platforms, REST, Leadership, Management, CI/CD Pipelines, Scripting, Ansible, Headless Software, Cloud Infrastructure, System Architecture Design, NoSQL, DevOps Engineer, Infrastructure as Code (IaC), API Integration, Cloudflare, Web Applications, SQL, Web Development, Performance Tuning, Jenkins, Cloud Computing, HTML, CSS, HTML5, System Architecture, XML, Autoscaling, Technical Architecture, Shell Scripting, Nagios, Graph Databases, Containers, Bash, Elasticsearch, Data Modeling, Bioinformatics, Data Engineering
Software Engineer
2006 - 2008
Youngculture Group
- Conducted business analysis, created the specification, and implemented the persistence layer for a web advertising platform.
- Implemented SQL performance tuning and wrote stored procedures for most critical cases.
- Wrote an Ajax-based web application for editing FreeMarker templates.
Technologies: Database Modeling, APIs, Linux, PostgreSQL, Java, Scalability, Web Platforms, Web Scraping, Jira, Web Applications, SQL, Web Development, Design Patterns, XML, Agile, Data Modeling
Linux Administrator
2006 - 2006
RealAction
- Administered Apache Tomcat, JBoss, NFS, DNS, and Samba servers.
- Diagnosed and solved network-related problems. Automated tasks that ran on a schedule.
- Wrote technical documentation and provided customer support.
Technologies: Linux, Scripting, SQL, DevOps, Shell Scripting
Experience
MentorPal
https://careerfair.mentorpal.org/A scalable AI framework where human mentors upload videos and then train natural language models that respond in real-time to students' questions.
When I joined the project, it had reliability and scalability problems. Video processing was failing and requiring manual intervention, and it couldn't handle load spikes. Other nonprofit institutions also use the system, so it had to be cost-efficient. There was a feedback mechanism to notify developers when something failed.
I've solved all these problems to make it production-ready: The system can now handle 100x load with predictable performance, handles failures, and is 10x cheaper. There is automated monitoring and alerting whenever errors happen, so the team is notified instantly.
When I joined the project, it had reliability and scalability problems. Video processing was failing and requiring manual intervention, and it couldn't handle load spikes. Other nonprofit institutions also use the system, so it had to be cost-efficient. There was a feedback mechanism to notify developers when something failed.
I've solved all these problems to make it production-ready: The system can now handle 100x load with predictable performance, handles failures, and is 10x cheaper. There is automated monitoring and alerting whenever errors happen, so the team is notified instantly.
Software Architect for an iOS Back End
https://www.coinlytics.com/The project was a mobile app powered by a back-end API, running on DigitalOcean, developed by a non-technical founder (kudos). The back end consisted of multiple worker nodes running Node.js services and using Redis for caching. The storage was MySQL with master-slave replication.
I was brought in to do an architecture review, load and performance testing, and tuning before the project went to production.
I re-architected the solution in less than three weeks to remove identified bottlenecks, resulting in a 40x speed-up and 300% cost reduction.
I was brought in to do an architecture review, load and performance testing, and tuning before the project went to production.
I re-architected the solution in less than three weeks to remove identified bottlenecks, resulting in a 40x speed-up and 300% cost reduction.
Crowdhouse Real Estate Platform
https://crowdhouse.ch/Crowdhouse is a leading proptech company in Switzerland that pioneered crowd investments and achieved over one billion transaction volumes in five years after it was founded. Main activities include management, brokerage and trading of investment properties, software solutions development, and operation of an online marketplace.
I worked as a senior software engineer and a tech lead in a team that was in charge of the acquisition process and also on internal business analytics tools.
My principal duties were:
• Architecture, system design, and documentation of the platform.
• Maintenance, optimization, and monitoring of the platform and cloud-based infrastructure.
• Technical discoveries, product discoveries, and data analysis.
• Integration with third-party services and systems.
When I joined, the engineering team got burned trying to adopt serverless. I managed to turn it around, and when I left, more than half of the platform was serverless, with an ongoing effort to replace the rest.
I worked as a senior software engineer and a tech lead in a team that was in charge of the acquisition process and also on internal business analytics tools.
My principal duties were:
• Architecture, system design, and documentation of the platform.
• Maintenance, optimization, and monitoring of the platform and cloud-based infrastructure.
• Technical discoveries, product discoveries, and data analysis.
• Integration with third-party services and systems.
When I joined, the engineering team got burned trying to adopt serverless. I managed to turn it around, and when I left, more than half of the platform was serverless, with an ongoing effort to replace the rest.
STRING
https://string-db.org/STRING is the largest database of known and predicted protein-protein interactions, with over 20 billion interactions among six million proteins.
I worked on parts of the data pipeline, adding new features and parallelizing data processing while developing new UI features.
I was a member of the international consortium that developed a specification (PSICQUIC) to enable computational access to molecular-interaction data resources, which resulted in a published Nature paper https://www.nature.com/articles/nmeth.1637.
I worked on parts of the data pipeline, adding new features and parallelizing data processing while developing new UI features.
I was a member of the international consortium that developed a specification (PSICQUIC) to enable computational access to molecular-interaction data resources, which resulted in a published Nature paper https://www.nature.com/articles/nmeth.1637.
Semantic CMS
As a co-founder of a next-generation semantic content-management system, I was wearing all hats: business development, product development, DevOps, hiring, etc. This role included market research, customer development (lean), and product development to a lesser degree.
Protein Abundance Database
https://pax-db.org/I implemented a data analysis with Python, crafted the website design, implemented various web services to expose the data (document and graph data stores), and created the web application in Node.js.
DNA-editing Design Tool
This is a genome-browser tool to aid in CRISPR guide selection. My responsibilities were to do data computations (CRISPR guides), writing the entire web app (both back and front end), and making sure it runs in production (DevOps).
Digital Ads Platform
A Java/PostgreSQL web app for digital ad distribution. I was the main back-end engineer in the early stages of the project in charge of data persistence with an object-relational mapper (Hibernate). To meet the high-performance demands, I had to write stored procedures.
Large German eCommerce Shop
http://www.galeria.deOne of the largest German eCommerce shops and marketplaces with around 80 million monthly visits. It's a microservice-oriented web application running on Kubernetes. I was the DevOps engineer in charge of CI/CD, monitoring and alerting, and infrastructure management.
Large eCommerce Platform
http://www.galeria.deOne of the biggest German eCommerce platforms. I was a DevOps engineer ensuring application performance, uptime, and scale, managing cloud environments. I also troubleshot incidents, identifying the root cause, and set up monitoring and alerting to detect issues quickly.
Education
2001 - 2008
Master of Science in Computer Science
University of Belgrade, Faculty of Electrical Engineering - Niš, Serbia
Certifications
APRIL 2023 - APRIL 2025
HashiCorp Certified: Terraform Associate (003)
HashiCorp
APRIL 2023 - APRIL 2026
AWS Certified Solutions Architect – Associate
AWS
Skills
Libraries/APIs
REST APIs, React, Node.js, Vue, Twilio API, Salesforce API, Segment.io, Terragrunt, Stripe, Stripe API, OpenAPI
Tools
Git, Terraform, Docker Swarm, Amazon Simple Queue Service (SQS), Amazon CloudWatch, GitHub, Sentry, AWS Deployment, Nagios, Amazon CloudFront CDN, Amazon Virtual Private Cloud (VPC), Amazon Elastic Container Service (ECS), Amazon Simple Notification Service (SNS), Keycloak, Amazon Cognito, Ansible, Amazon EKS, Jira, AWS CodeDeploy, Puppet, Jenkins, Multiple Listing Services (MLS), Grafana, VPN, MQTT, Amazon ElastiCache, AWS Fargate, AWS Key Management Service (KMS)
Languages
TypeScript, SQL, JavaScript, Python, Java, HTML, CSS, HTML5, XML, Bash, GraphQL, PHP
Frameworks
Express.js, Swagger, Serverless Framework, Bootstrap 3, Flask, Next.js, AdonisJS, Laravel
Paradigms
Web Architecture, Microservices, DevOps, Web Application Architecture, REST, Agile, Microservices Architecture, Serverless Architecture, Continuous Delivery (CD), Management, Design Patterns, Load Testing
Platforms
AWS Lambda, Docker, Linux, Amazon Web Services (AWS), Salesforce, Amazon EC2, AWS Elastic Beanstalk, Kubernetes, Twilio, Heroku, New Relic, AWS IoT, AWS IoT Core, Azure, Vanta
Storage
Elasticsearch, Database Modeling, PostgreSQL, NoSQL, MySQL, Amazon DynamoDB, MongoDB, Data Pipelines, Amazon S3 (AWS S3), Redis Cache, Redis, Neo4j, MariaDB, Graph Databases, Amazon Aurora, ArangoDB
Industry Expertise
Project Management, Bioinformatics
Other
Serverless, APIs, Software Architecture, Back-end, Technical Leadership, Web Development, Architecture, Code Architecture, Full-stack, RESTful Microservices, DevOps Engineer, SaaS, Cloud Architecture, AWS Cloud Architecture, Scalability, Web Scalability, Solution Architecture, Web Platforms, Leadership, Cloud Infrastructure, System Architecture Design, Infrastructure as Code (IaC), API Integration, Web Applications, Minimum Viable Product (MVP), Cloud Computing, AWS DevOps, System Architecture, Technical Architecture, Containers, Startups, Data Modeling, Team Leadership, Data Processing, Data Aggregation, CTO, eCommerce, CI/CD Pipelines, Scripting, Web Scraping, Headless Software, Content Management Systems (CMS), Lean Startups, Lean Product Development, Amazon API Gateway, Amazon RDS, Container Orchestration, Autoscaling, Disaster Recovery Plans (DRP), Shell Scripting, Strategy, SOC 1, SOC 2, Observability, Data Engineering, Distributed Systems, API Gateways, Performance Tuning, Video Chat, Data Analysis, University Teaching, Data Visualization, Software as a Service (SaaS), Segment, Epicor, Cloudflare, Cloudinary, Digital Asset Management, AWS CodePipeline, Security, Crypto, Enterprise Resource Planning (ERP), TypeORM, Load Balancers, Octopus Deploy, Data Warehousing, WebSockets, AWS Certified Solution Architect, HAProxy, Prometheus, Customer Relationship Management (CRM), Internet of Things (IoT), Custom Solutions, Artificial Intelligence (AI), New Products, Automatic Speech Recognition (ASR), FastAPI, Anthropic, Audio Processing, Machine Learning Operations (MLOps)
Collaboration That Works
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
1
Share your needs
Discuss your requirements and refine your scope in a call with a Toptal domain expert.
2
Choose your talent
Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.
3
Start your risk-free talent trial
Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.
Top talent is in high demand.
Start hiring