Volodymyr Vysotskyi
IOS App Developer at Фриланс
Kyiv, Ukraine
Summary
🤩
Rockstar🎓
Top SchoolVolodymyr Vysotskyi is an iOS app developer with nine years of software experience based in Kyiv, Ukraine, who builds apps from scratch with modern interfaces that follow Human Interface Guidelines and robust local data and notification handling. He brings practical cross-discipline skills—combining a Computer Science bachelor's with an LLM—that help him balance technical design, privacy, and product requirements. As a freelancer since 2022 he has implemented features like location tracking with movement visualization and reliable local reminders, plus REST API integrations and offline storage. Beyond mobile, his open-source contributions to heavyweight Apache projects such as Drill and Calcite show deep backend experience in Java, query optimization, and refactoring for performance. That blend of front-end iOS polish and backend systems thinking makes him effective at shipping end-to-end, production-ready features.
9 years of coding experience
Bachelor's degree, Computer science, Bachelor's degree, Computer science at APEPS department of Igor Sikorsky Kyiv Polytechnic InstituteMaster of Laws - LLM, Law, Master of Laws - LLM, Law at National Academy of Internal Affairs of Ukraine
English, Украинский, Русский
Stackoverflow
661reputation
22kreached
26answers
0questions
Github Skills (20)
apache-drill10
databases10
query-optimization10
java10
javas10
sql10
relational-databases10
sql-database10
database10
sql-parser9
calc9
apache-calcite9
big-data9
parsing9
data-engineering8
Programming languages (4)
Github contributions (5)
apache/drill
Mar 2017 - Jan 2023
Apache Drill is a distributed MPP query layer for self describing data
Role in this project:
Back-end Developer
Back-end DeveloperContributions:1 release, 330 reviews, 240 commits in 5 years 10 months
Contributions summary:Volodymyr's contributions appear focused on fixing bugs and implementing new features related to the functionality of Apache Drill. The commits demonstrate a focus on improving the performance and functionality of string and decimal functions, in addition to enhancements and bug fixes for various features. The user interacted with Java code extensively and performed refactoring within the code.
jdbcdatastreambig-datadatabasehadoop
apache/calcite
Aug 2017 - Dec 2022
Apache Calcite
Role in this project:Back-end Developer
Back-end DeveloperContributions:10 reviews, 36 commits, 34 PRs in 5 years 5 months
Contributions summary:Volodymyr primarily contributed to the Apache Calcite project by addressing various issues related to SQL query optimization and execution. Their work involved fixing bugs in window function handling, optimizing query plans, and improving the handling of "IS DISTINCT FROM" and "NOT IN" operators. The user also refactored and improved the codebase, including updating existing rules and adding new validation checks for data and time literals.
geospatialapache-calcitesqlapachebig-data
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