Sergii D.
Odessa, Ukraine
100%
Job Success
Top Rated Plus
Front end Developer React JavaScript Web Developer LONG-TERM PROJECTS
$40.00/hr
⭐️⭐️⭐️⭐️⭐️ Top 1% Expert-Vetted Web Developer on Upwork
📍 No short-term projects. Sorry.
📞 Kick-off with the team is a mandatory step.
🧨 Availability for a quick project start.
★ Top-100 Service Provider by Clutch
★ 500M+ Raised by our clients
★ 99+ International Awards
★ 15 years of expertise with clients like:
NOKIA, OPERA, OPPO, UDEMY, COREL, CREATIVE MARKET, AUTH0 etc.
Welcome to my profile page:
👨💻 I am a front end developer with 10+ years of experience in the IT industry, working across a wide range of projects and industries. Over the years, I’ve honed my skills with modern front end technologies, consistently delivering high-quality projects using React, Typescript, NextJS, Vue.
🏆 Expert-Vetted front end developer.
🏆 Head of development at The Best Creative Agency in Ukraine 2018 by Upwork.
🏆 Managed projects for 20+ Upwork clients and delivered over 50 fully developed products.
My main skills:
・10+ years of experience and over 100 projects made with React, Redux, GraphQL, Next, Gatsby, Vue, JavaScript (ES6-ES8), Typescript, NodeJS, Express, NestJS, Fastify.
・Redux, Redux-Saga.
・MongoDB, PostgreSQL, MySQL.
・Scss, Sass, PostCSS, HTML5, CSS3.
・Building maintainable design systems with Storybook.
・Client-side performance including AMP and PWA apps.
・Accessibility, 508 Compliance support.
・SEO Optimization.
・Cross-browser/cross-platform manual testing.
・Automation QA: Cypress, Puppeteer, Playwright, Jest, Selenium.
・Tooling: Webpack, Git, NPM.
I am a web developer with full-stack experience. I work on both the front-end and back-end. I know HTML5, CSS3, and JavaScript (JS). I use frameworks like React (ReactJS), Node.js, Express.js, TypeScript, NestJS, Next.js, and Nuxt.js. I build fast websites with Gatsby and GraphQL.
For front-end, I use Bootstrap, Tailwind CSS, and Sass to make websites look good and work well. For back-end, I connect to databases like MongoDB, PostgreSQL, MySQL, and DynamoDB. I use AWS, Google Cloud, and Microsoft Azure to run apps.
I build RESTful APIs to connect the front-end and back-end. I use Git, GitHub, and GitLab for version control. I use Firebase for real-time database management and Cypress for testing.
I create SaaS solutions for businesses. I build CMS websites with WordPress, Shopify, HubSpot, Craft CMS, and Ghost CMS. I use Jira, Trello, and Asana for project management. I use Slack and Microsoft Teams for team communication.
I handle all parts of web development. I deliver high-quality results for clients.
Work history
Work history
30 minute consultation
Mar 25, 2025
-
Apr 16, 2025
No feedback given
Private earnings
Website development
Sep 19, 2024
-
Feb 25, 2025
Private earnings
QA Testing for the Application
Aug 5, 2024
-
Nov 20, 2024
"We were very impressed at the diligent QA! We have a React Native / Expo mobile application. Sergii worked closely with the developer to coordinate successful releases, type up detailed…
Private earnings
Senior React Developer for Code Review AND Bug Fixes
May 13, 2024
-
Nov 15, 2024
Private earnings
Web Development Next.js
Feb 6, 2024
-
Jul 22, 2024
Private earnings
Dropshipping SaaS Platform using T3 Stack
Sep 15, 2023
-
May 22, 2024
No feedback given
Private earnings
Develop Data Dashboard System (React.js, Node.js)
Dec 13, 2021
-
May 22, 2024
No feedback given
Private earnings
React js Dev - Decentralized Exchange
Apr 5, 2021
-
May 22, 2024
No feedback given
Private earnings
Homehandy. Application development
Aug 11, 2021
-
Jun 19, 2023
No feedback given
Private earnings
Looking for a full stack developer to create a new sass web application from scratch
Jun 30, 2022
-
Jul 26, 2022
"Good work & great communication."
Private earnings
30 minute consultation
Apr 14, 2025
-
Present
Job in progress
Private earnings
Webflow page buildout
Apr 1, 2025
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Present
Job in progress
Private earnings
Webflow backend + member page creation
Feb 10, 2025
-
Present
Job in progress
Private earnings
Front end developer | Wordpress
Nov 11, 2024
-
Present
Job in progress
Private earnings
UX/UI design for websites and CRM
Oct 14, 2024
-
Present
Job in progress
Private earnings
Frontend development based on Figma designs
Aug 9, 2024
-
Present
Job in progress
Private earnings
Looking for a web developer to work closely with on our existing website
Mar 28, 2023
-
Present
Job in progress
Private earnings
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Project catalog
Get started working with Sergii quickly with these predefined projects.
Get started working with Sergii quickly with these predefined projects.
You will get a web app from expert front end developer | NodeJS, ReactJS, PostgreSQL
From $6,000
70 days delivery
You will get seamless CMS from expert front end developer | Sanity, Prismic, Strapi
From $2,500
30 days delivery
You will get Web App in 3 months from expert front end developer | NextJS, NodeJS, React
From $5,000
70 days delivery
You will get Open AI Integration | GPT-3.5 | ReactJS from expert front end developer
From $500
5 days delivery