Kostiantyn A.
Full-Stack JavaScript Developer | React/Next/Node/Express
Hi everyone 👋 I'm a high-skilled (7+ years) Full-Stack Developer. I have 8,000+ hours of a proven track record and 16 completed jobs here on Upwork. Through many projects, I have mastered problem-solving skills and just fell in love with what I'm doing. Creating new products is what brings me much more joy than anything else. I especially like small and big projects that require uncommon approaches and use of the most efficient methods. My skills: — JavaScript/ES6; — Typescript; — Cursor, Claude Code; — Node.js, Express.js; — React.js/Next.js; — Redux/Redux Toolkit/Tanstack-Query/Zustand/React Context; — HTML5, CSS3 and LESS (SASS); — React-Native IOS/Android, Expo; — Material UI, Ant Design, styled-components, Tailwind; — Agile: Jira, Trello, Notion, Linear and Slack; Other: Webpack, REST APIs, Git, Docker, GitHub Actions (CI/CD pipeline). Databases: MongoDB, Mongoose, Firebase/Firestore, Planescale, Supabase, ClickHouse Familiar with: AWS, Electron, Inngest, Redis. I'm open to both part-time and full-time positions, so feel free to send me an invitation any time! You'll be rewarded once we work together :)
Earnings and projects
Last 6 months ÷ 6
Last 6 months: $15k
Billed in all: $258,958$259k
$15k in the last 6 months
Across 19 contracts
Earnings, last 30 days
Skill rankings: Top 4% in ExpressJS
Ranked by MRR among everyone on Upwork with the skill.
- #9Mobx103 freelancers · 🇺🇦 #5Top 9%🇺🇦#5 of 30
- #14styled-components191 freelancers · 🇺🇦 #8Top 7%🇺🇦#8 of 26
- #58Material UI1,027 freelancers · 🇺🇦 #18Top 6%🇺🇦#18 of 142
- #165Redux3,245 freelancers · 🇺🇦 #58Top 5%🇺🇦#58 of 492
- #237ExpressJS5,651 freelancers · 🇺🇦 #24Top 4%🇺🇦#24 of 363
- #359RESTful API6,064 freelancers · 🇺🇦 #39Top 6%🇺🇦#39 of 351
- #617MongoDB10,865 freelancers · 🇺🇦 #75Top 6%🇺🇦#75 of 735
- #1,757Node.js25,795 freelancers · 🇺🇦 #199Top 7%🇺🇦#199 of 1,711