Tomislav Kucar, Developer in Zagreb, Croatia
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Tomislav Kucar

Verified Expert  in Engineering

Python Developer

Zagreb, Croatia
Toptal Member Since
October 26, 2020

Tomislav offers an extensive background in all areas of digital products and roles, including site reliability engineering, full-stack development, and operations. Thanks to his enthusiasm for learning new tech, technical expertise, and high-quality standards, Tomislav can hit the ground running and meaningfully contribute to any project. Above all, what attracts Tomislav to a project is building solutions that have a long-term impact and solve real problems.


Python 3, FastAPI, SQLAlchemy, GraphQL, Redis
Python 3, FastAPI, PostgREST, Kubernetes, Redis, React
Python 3, FastAPI, Celery, RabbitMQ, Google Cloud, Amazon Web Services (AWS)...




Preferred Environment

Python 3, Linux, Docker, Kubernetes

The most amazing...

...thing I've developed is a distributed high-availability low-latency server for an MMO, handling more than 10,000 concurrent heavy clients.

Work Experience

Senior Software Engineer

2023 - 2023
  • Migrated and refactored legacy PHP GraphQL API to new Python API using Strawberry and FastAPI.
  • Aided existing developers in learning best Python practices and helped them ramp up on the new solution.
  • Documented and analyzed existing solutions to provide suggestions and create tickets, tasks, and epics for the new solution. Wrote the documentation and created the test suite for the new solution before off-boarding.
Technologies: Python 3, FastAPI, SQLAlchemy, GraphQL, Redis

Solution Architect and DevOps Engineer

2021 - 2023
  • Refactored and migrated the legacy GraphQL API from Python monolith (Starlette) to Next.js microservice, including modifying the front end (TypeScript + React).
  • Worked as a senior Python engineer maintaining the legacy solution; a little more than two years later, as a solution architect, I led the work on phasing out the same solution for the new components.
  • Implemented and presented proof of concept solutions for existing problems and greenfield projects. This included writing and updating prestudy documents and necessary meetings, encompassing the whole application lifecycle.
  • Worked as an individual contributor on solving complex problems with legacy and services that posed issues to newer team members since I had a better overview of the system and wider experience.
Technologies: Python 3, FastAPI, PostgREST, Kubernetes, Redis, React

Site Reliability Engineer | IT Automation

2020 - 2021
  • Worked as a multiple products owner involved in designing and implementing in-house solutions. and as an individual contributor working on internal solutions and existing solutions refactoring.
  • Worked on infrastructure planning and maintenance across multiple cloud providers.
  • Supported teams with SRE and related tech advising.
Technologies: Python 3, FastAPI, Celery, RabbitMQ, Google Cloud, Amazon Web Services (AWS), Docker Compose, SaltStack

Site Reliability Engineer

2018 - 2020
  • Implemented and optimized the application lifecycle management system, which included enhancing analytics, measuring, and helping to build KPI dashboards.
  • Worked with existing teams and managers to reduce organizational silos and turnaround time, effectively cutting down on overhead expenses.
  • Designed and implemented APIs using Flask and FastAPI.
  • Helped leverage the existing tooling and applied automation.
Technologies: Application Lifecycle Management (ALM), Key Performance Indicators (KPIs), LXC, Linux, Flask, FastAPI, SQLAlchemy, Keycloak, Team Leadership

Full-stack Web Developer

2016 - 2017
SunnyBoy Entertainment
  • Discussed, analyzed, and strategized the product design with UI/UX experts.
  • Designed, developed, and maintained a complex immersive VR website through all stages of the agile development lifecycle.
  • Ensured stability, security, and rapid development through TDD and CI/CD.
  • Automated the Linux server set up, which included hardening and website deployment to ensure easy, cheap, and fast website updates.
Technologies: Three.js, Flask, Web Scraping, Python, Test-driven Development (TDD), CI/CD Pipelines

Full-stack Web Developer

2014 - 2016
  • Designed, implemented, and maintained complete websites built with various technologies.
  • Set up various tech stacks (LAMP, LEMP), secured, maintained Linux boxes, and deployed to OpenVZ and KVM cloud instances.
  • Ensured client satisfaction through extensive communication and by employing Agile principles, which included a series of short sprints (discovery, design, development, and testing) to maximize ROI.
Technologies: Bootstrap, jQuery, Laravel, Flask, Django, PHP, PostgreSQL, Joomla, WordPress, KVM, OpenVZ, NGINX, Linux, LAMP, Agile, Team Leadership

Lead Software Engineer

2013 - 2015
Idris Studio
  • Created a distributed high availability server for a massively multiplayer online game, serving 10,000+ concurrent clients.
  • Oversaw software engineers, game developers, and designers, including communicating over IRC and mail, tracking tasks using Kanban boards, implementing source code versioning, and managing assets using Git and Mercurial.
  • Designed and oversaw the implementation of a complete web presence for the project.
  • Helped set up and maintain a big data system using Apache Spark, Pig, and Hadoop.
Technologies: Git, PostgreSQL, Distributed Systems, C++, JavaScript, Panda3D, Python 2, Unity3D, C#, Team Leadership

KaT Operating System

While in university, my colleague and I developed an operating system in modern C++. The OS has a simple shell, a monolithic kernel, and an ISO 9660 file system. Every step from building the cross compiler to documentation is automated; the only prerequisites are VirtualBox and Vagrant. This set up allowed us to implement rapid development and testing.

Education Platform

Developed a brand new education platform (LMS) for a nonprofit organization based on concepts of SSR and other up-to-date learning methods not usually applied in classic LMS (this included user-created interactive apps) and integrated it as part of their existing solution based on Open edX. I then updated and maintained the platform for a while now.
2017 - 2020

Bachelor's Degree in Software Engineering

Algebra University College - Zagreb, Croatia

2013 - 2017

Specialization in Economics and Business

Hrvatski kralj Zvonimir - Krk, Croatia


REST APIs, SQLAlchemy, React, jQuery, Three.js, Beautiful Soup, PostgREST


Git, Adobe Creative Suite, 3D Studio Max, Photoshop CS6, NGINX, Vagrant, Makefile, GCC, wxPython, Keycloak, Celery, RabbitMQ, Docker Compose, SaltStack


Python, HTML, CSS, JavaScript, SQL, Java, C#, Python 2, C++, PHP, C, Assembler, Python 3, GraphQL


Databases, PostgreSQL, Microsoft SQL Server, Redis, Google Cloud


Linux, Open edX, LAMP, KVM, WordPress, Joomla, Docker, Android, Kubernetes, Amazon Web Services (AWS)

Industry Expertise

Accounting, Marketing, Project Management, Cybersecurity


Django, Flask, .NET, Unity3D, Panda3D, Laravel, Bootstrap, Selenium


Agile, Scrum, Application Lifecycle Management (ALM), Test-driven Development (TDD)


Documentation, FastAPI, Learning Management Systems (LMS), Team Leadership, APIs, CTO, Finance, Statistics, Microsoft 365, IT Networking, Operating Systems, Data Structures, Algorithms, Decision Support Systems, Communication, Autodesk Maya, Distributed Systems, OpenVZ, LXC, Key Performance Indicators (KPIs), Tkinter, Reverse Engineering, Web Scraping, Security, CI/CD Pipelines

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