Лев

Lev Saltsyn
Front-End Developer

[відкрити контакти](див. вище в блоці «контактна інформація») (Telegram)
[відкрити контакти](див. вище в блоці «контактна інформація»)
Linkedin
Git

​ ​ ​ ​ ​ ​ SUMMARY

●​ Front-End Developer with 5+ years of professional experience building web applications and
user-facing features for product and platform teams. Strong hands-on experience with React,
Next.js, TypeScript, and modern front-end architecture, including feature development, legacy
code refactoring, REST API integration, testing, and performance optimization.
●​ Experienced in delivering new UI functionality, modifying and improving existing features,
maintaining code quality standards, and collaborating closely with cross-functional teams through
Jira-based workflows. Confident in estimating tasks, clarifying requirements, communicating
progress and blockers, and shipping reliable front-end solutions aligned with acceptance criteria.
●​ Strong background in scalable component-based development, client-server communication, test
coverage, dependency maintenance, and CI/CD workflows using GitHub and CircleCI. Also has
additional experience with Web3 integrations and blockchain-based products.
●​ English: Intermediate+

TECHNICAL SKILLS

●​ Frontend Technologies: TypeScript (strict mode), JavaScript (ES2023+), React (Hooks,
Context, Suspense), Next.js (App Router, Server Components, SSR, SSG, ISR), JSX/TSX,
HTML5, CSS3, SCSS/SASS, Tailwind CSS, BEM, Responsive Design, Accessibility (a11y),
Cross-browser compatibility
●​ Next.js: App Router, Pages Router, Server-Side Rendering (SSR), Static Generation (SSG),
Client/Server Components, Routing, API integration, Performance optimization
●​ API & Data: REST API integration, client-server communication, JSON, async data handling,
error handling, form flows
●​ Build & Dev Tools: Git, GitHub, GitLab, Bitbucket, CircleCI, CI/CD pipelines, npm, yarn,
Webpack, Rollup.js, Babel, Vercel
●​ Testing: Jest, React Testing Library, Hardhat, Truffle, Mocha, Chai (Unit & integration testing)
●​ Product Delivery: Figma (design handoff), Jira, Confluence, Agile / Scrum, Task
decomposition, Effort estimation, Feature delivery lifecycle, Refactoring, Bug fixing,
 Dependency management
●​ Additional: Node.js Solidity, web3.js, Wallet integration DeFi protocols, NFT standards,
Docker

●​ AI coding assistants: Claude Code (Opus 4.5), GitHub Copilot, GPT-5.3 (Codex), AI-assisted
debugging, refactoring, code generation, test generation workflows

PROFESSIONAL EXPERIENCE

​
Development of financial software. «Finline» ​
​
Frontend Engineer / Full-Stack Engineer​
02/2023 – 09/2025 ​
Project: ReelSense-style product platform / interactive web application​
​
Technologies: React.js, Next.js, TypeScript, Wagmi, REST APIs, Jest, React Testing Library, Solidity,
Hardhat, Ethers.js, Chai, Truffle, web3.js, TypeScript, React.js, Walletconnect, Jira, GitHub

Responsibilities & Achievements:

-​ Developed new front-end features using React and Next.js in accordance with product
requirements and acceptance criteria
-​ Modified and improved existing UI functionality to support evolving business needs
-​ Refactored front-end codebase to improve maintainability, scalability, and development standards
-​ Integrated REST APIs and handled client-server communication for dynamic product functionality
-​ Designed and developed smart contract architecture for a Web3 protocol
-​ Implemented ERC-20 and ERC-721 based mechanics
-​ Prepared technical documentation and deployment guides
-​ Deployed and maintained contracts across Ethereum, Arbitrum, Base, and Polygon networks
-​ Contributed to technical documentation and release preparation
-​ Contributed to CI/CD workflows using GitHub and CircleCI
-​ Collaborated with designers, product stakeholders, and engineers to deliver production-ready UI
features

​
«Distributed lab»​
​
Frontend Engineer / Full-Stack Engineer
06/2022 – 01/2023
Project: Web application platform with interactive user flows
​
Technologies: React.js, Next.js, TypeScript, JavaScript, REST APIs, Jest, React Testing Library, Solidity,
ERC20, web3.js, Hardhat, Mocha, Truffle, Figma, SCSS, HTML, BitBucket, Jira
Responsibilities:

-​ Built and delivered front-end features using React and Next.js
-​ Developed reusable UI components based on Figma designs
-​ Integrated REST APIs and implemented client-side business logic
-​ Improved application structure and front-end architecture for better maintainability
-​ Wrote tests for core functionality and supported feature reliability
-​ Developed smart contracts and issued a custom ERC-20 token
-​ Implemented unit testing using Mocha
-​ Deployed contracts on Ethereum mainnet
-​ Designed and built frontend architecture for the Web3 application
-​ Participated in Agile team processes, including task clarification and delivery discussions

«Vanilline» ​
​
Frontend Developer
04/2022 – 05/2022
Project: E-commerce website

Technologies: React.js, Next.js, JavaScript, SCSS, HTML5, CSS3, Vercel, EmailJS, Jira, Figma

Responsibilities:

-​ Designed front-end architecture and component structure
-​ Implemented responsive UI based on approved designs
-​ Integrated external services and client communication flows
-​ Managed repositories, deployment setup, and release preparation
-​ Ensured cross-browser and mobile compatibility
-​ Supported feature updates and front-end improvements

Mobiform​
​
Front-End Developer
10/2020 – 03/2022
Project: Online platform with e-commerce and 3D kitchen editor

Technologies: TypeScript, Stencil.js, Ionic, JavaScript, Firebase (Firestore, Cloud Functions),
Rollup.js, x3dom, HTML5, SCSS

Responsibilities:

-​ Developed a 3D kitchen editor using x3dom
-​ Built CRM functionality for customer management
 -​ Converted designs into scalable TSX components
-​ Applied OOP principles in component and service design
-​ Ensured performance optimization and cross-platform compatibility
-​ Worked on feature enhancement and ongoing front-end improvements

Momo (陌陌) ​
​
Front-End Developer
01/2020 – 10/2020
Project: Social platform with chat and video communication
​
Technologies: React.js, Redux, Node.js, JavaScript, REST APIs, Webpack, SASS, HTML5,
CSS3

Responsibilities:

-​ Built the platform from scratch, including UI and client-side logic
-​ Integrated state management using Redux
-​ Implemented API interactions and JSON-based data flows
-​ Refactored and modernized legacy code.
-​ Delivered responsive, cross-browser compatible functionality
-​ Participated in feature delivery and codebase modernization

EDUCATION ​

●​ React.js for Web Development — IT School
of Professional Programming
●​ Frontend Development (JavaScript + React)
— Thinknetica
●​ Basics of Web UI Development —
Prometheus / Lviv IT School
●​ Aviation Computer Systems Engineer —
National University “Kyiv Aviation Institute"