Ivan Longin, Developer in Zagreb, Croatia
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Ivan Longin

Verified Expert  in Engineering

Software Developer

Zagreb, Croatia
Toptal Member Since
November 5, 2019

Ivan is a senior software engineer with over 11 years of experience in back-end development, web applications, DevOps, and data management. He has been focused on highly distributed and scalable systems and has worked as an international team leader and system designer. Ivan has strong communication and organizational skills, together with project management experience.


Python, Django, ClickHouse, PostgreSQL, SQLite...
Python, Django, PostgreSQL, Kubernetes, AWS IoT
UV Partners, Inc.
Node.js, GraphQL, AWS Lambda, MongoDB, TypeScript, AWS IoT




Preferred Environment

Vim Text Editor, Git, Linux

The most amazing...

...project I've worked on was a generic system for extracting various data from company websites.

Work Experience

Senior Software Engineer

2022 - PRESENT
  • Developed a new product for data management as an addition to the company's "flagship" product, DVC, from scratch.
  • Worked on connecting CLI and SaaS parts of a product.
  • Worked on improving performance using the Clickhouse database.
Technologies: Python, Django, ClickHouse, PostgreSQL, SQLite, Machine Learning Operations (MLOps)

Senior Software Engineer

2021 - 2022
  • Developed a core business logic for property management.
  • Developed a bulk import tool to import large amounts of property data via various interfaces.
  • Developed and maintained a public API for dealing with property data.
Technologies: Python, Django, PostgreSQL, Kubernetes, AWS IoT

Back-end Engineer

2020 - 2021
UV Partners, Inc.
  • Developed serverless back-end system for gathering IoT data from various air cleaning devices.
  • Maintained and improved GraphQL API for dashboard application.
  • Refactored the codebase to be less coupled and more testable.
Technologies: Node.js, GraphQL, AWS Lambda, MongoDB, TypeScript, AWS IoT

Senior Software Engineer | Team Lead

2017 - 2021
Cial D&B
  • Developed a custom ETL process in Python 3 with the corresponding infrastructure using a microservice architecture with Docker, Kubernetes, and Amazon AWS.
  • Worked on a generic scraping service extracting company data from their web pages.
  • Built and maintained a central logging system using ELK stack.
  • Served as the project leader of a generic payment platform.
  • Led the report automation project and a small remote team.
  • Worked on the infrastructure using Amazon AWS, CircleCI, and more.
  • Developed a front-end single sign-on application in React.
  • Built and maintained an auto-scaled Kubernetes cluster.
Technologies: RabbitMQ, PostgreSQL, Elasticsearch, MongoDB, Amazon Web Services (AWS), Docker, Kubernetes, React, Node.js, Flask, Python 3

Python Engineer

2020 - 2020
  • Developed an ETL process for fetching, cleaning, transforming, and saving betting data.
  • Developed scrapers for fetching betting data through an API or Selenium/Scrapy.
  • Maintained a PostgreSQL database and a GraphQL API using AWS cloud services.
Technologies: Amazon Web Services (AWS), Scrapy, Selenium, Rust, GraphQL, Web Scraping, PostgreSQL, Python

Senior Software Engineer

2014 - 2017
Powerlinx Inc.
  • Developed a B2B system for matching companies for collaborations, M&A, etc.
  • Worked on back-end core logic in Node.js and Python.
  • Managed database modeling and maintenance for MongoDB.
  • Developed a search engine using Elasticsearch and an ETL stack central logging system.
  • Maintained and created Amazon AWS infrastructure, including VPC, security, CI/CD processes, instances, EBS, etc.
Technologies: Linux, Elasticsearch, MongoDB, AngularJS, RabbitMQ, Docker, Amazon Web Services (AWS), Python 3, Node.js

Software Engineer

2012 - 2014
  • Developed a large-scale distributed system for push notifications.
  • Performed REST API modeling and business logic using Node.js and Groovy.
  • Headed database modeling and cluster maintenance for MongoDB and Microsoft SQL.
  • Developed a billing system with rule engines using Groovy, Grails, and Drools.
Technologies: Linux, Grails, Groovy, Microsoft SQL Server, Cassandra, Elasticsearch, Redis, MongoDB, Node.js


B2B system for matching companies for collaborations, M&A, etc.


A betting service for odds comparison and to help to find the best deals. I was a Python/Rust back-end engineer, working on the ETL process and web scraping, as well as maintaining a PostgreSQL database and a GraphQL API.
2007 - 2012

Master of Science Degree in Information and Communication Technology

Faculty of Electrical Engineering and Computing - Zagreb, Croatia


Machine Learning

Stanford online (Coursera)


Startup Engineering

Stanford online (Coursera)


Algorithms: Design and Analysis, Part 1

Stanford online (Coursera)


Functional Programming Principles in Scala

École Polytechnique Fédérale de Lausanne (Coursera)


MongoDB for DBAs



Node.js, React


Git, Vim Text Editor, RabbitMQ


Python, Python 3, JavaScript, Groovy, GraphQL, Rust, Go, TypeScript, Scala


MongoDB, Elasticsearch, PostgreSQL, ClickHouse, Microsoft SQL Server, Redis, Cassandra, SQLite


ETL, Database Design, Microservices Architecture, Functional Programming


Flask, Grails, AngularJS, Selenium, Scrapy, Django


Linux, Amazon Web Services (AWS), Kubernetes, Docker, AWS Lambda, AWS IoT

Industry Expertise

Project Management


Mentorship, Payment Gateways, Web Scraping, Machine Learning, Distributed Systems, Algorithms, Machine Learning Operations (MLOps), Startups, Software Engineering

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