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Pavel Tumash
Verified Expert in Engineering
Front-end Engineer and Software Developer
Kraków, Poland
Toptal member since March 2, 2023
Bio
Pavel is a highly-experienced front-end engineer with more than seven years of professional experience, including four years of remote work. His expertise lies in designing and implementing intuitive and user-friendly interfaces for various websites and web applications. Pavel is particularly passionate about utilizing React, TypeScript, and GraphQL to bring his designs to life.
Portfolio
Cendars Tech Labs FZCO
React, TypeScript, Tailwind CSS, Redux, WebSockets, AI SDK...
FORMULA PAYMENTS, INC.
React, TypeScript, Front-end, Tailwind CSS, Next.js, Drizzle, Figma, Clerk...
The Lotto Factory
Front-end, React, Angular, Shadcn, Tailwind CSS, Artificial Intelligence (AI)
Experience
- Front-end - 11 years
- JavaScript - 10 years
- HTML - 8 years
- React - 7 years
- CSS - 7 years
- Redux - 5 years
- TypeScript - 4 years
- GraphQL - 2 years
Work Experience
Senior Full-stack Developer
2025 - 2026
Cendars Tech Labs FZCO
- Architected real-time data pipelines that handled 90+ websocket-driven cache patches per second using RTK Query cache patching and batching, keeping tables/charts responsive under continuous market streams.
- Integrated websocket-driven trading flows for crypto orders and live executions, bridging streaming updates into Redux/RTK Query state so order status, fills, and positions are updated in near real time across terminal views.
- Built a reusable AG Grid table platform with 40+ custom cell renderers, streaming-friendly behaviors (freeze-on-hover, external sort preservation), and cross-component coordination via a shared Grid API registry.
- Delivered multi-library charting with real-time updates by integrating TradingView (custom datafeed and bar stitching) and Lightweight Charts/ECharts, including websocket-safe guards for out-of-order ticks and stable incremental updates.
- Optimized runtime performance for a large React codebase by adopting React Compiler, route-level lazy loading, and virtualization (AG Grid/react-window), supporting high-density UIs and continuous streaming updates.
- Applied AI-supported performance debugging by pairing profiler traces with AI-driven hypothesis iteration to quickly isolate re-render hot spots in streaming tables and charts and validate fixes.
- Integrated AI-driven trading suggestions by wiring LLM-generated signals into the terminalux, and by adding guardrails (confidence thresholds, explainability text, and safe defaults) to prevent over-triggering and improve user trust.
Technologies: React, TypeScript, Tailwind CSS, Redux, WebSockets, AI SDK, Model Context Protocol (MCP), High-load, Node.js, React Native, LLM Integration, TradingView, Charts, AI-assisted Development, Full-stack, Cursor AI, Agentic AI, AI Development, Web3, Artificial Intelligence (AI)
Front-end Developer
2025 - 2025
FORMULA PAYMENTS, INC.
- Developed a fintech application for managing payouts between vendors and buyers, ensuring a smooth and secure financial UI.
- Set up a modern front-end architecture using Next.js and Tailwind CSS to deliver a responsive and scalable user interface.
- Helped with back-end integration and system architecture planning to ensure performance, maintainability, and smooth collaboration across teams.
Technologies: React, TypeScript, Front-end, Tailwind CSS, Next.js, Drizzle, Figma, Clerk, Vercel, Shadcn, Artificial Intelligence (AI)
React Developer
2024 - 2024
The Lotto Factory
- Led the successful migration of an outdated AngularJS admin panel to a modern React-based architecture.
- Implemented best practices in React, including component-based architecture, which reduced code complexity and facilitated easier maintenance and scalability.
- Coordinated back-end teams to ensure smooth and correct API calls were done during the rewrite process.
Technologies: Front-end, React, Angular, Shadcn, Tailwind CSS, Artificial Intelligence (AI)
Front-end Developer
2023 - 2024
FKA Brands
- Integrated AI search and subscription functionality into an eCommerce website, increasing conversion rates and usability for the client.
- Rewrote an old jQuery website to meet modern standards, significantly improving its performance and enhancing accessibility and SEO.
- Automated the deployment process, improving the speed and quality of the release cycle.
Technologies: Front-end, JavaScript, HTML, CSS, eCommerce, User Interface (UI), User Experience (UX), BigCommerce, Handlebars, Stencil.js, Shogun, Algolia, Ordergroove, Tailwind CSS, Material UI
Front-end Engineer
2021 - 2023
Toptal
- Led the effort to migrate existing monolith applications to a monorepo structure and implement a set of tools to streamline the process as a member of the Toptal core team.
- Optimized our CI cost and runtime, resulting in a 30% increase in speed for test runs.
- Collaborated with the design team to develop a web application to manage event attendance for a community of talented individuals.
Technologies: React, TypeScript, Apollo, GraphQL, Storybook, Jest, Slack API, HTML, CSS, Git, Front-end, Next.js, HTML5
Senior Front-end Engineer
2019 - 2021
EPAM Systems
- Utilized the Web Components, Shadow DOM, Stencil.js, React, and Storybook to create a unified design library capable of supporting a wide range of front-end applications, from legacy jQuery apps to the latest React and Angular technologies.
- Set up a monitoring tool, Sentry, which effectively tracks and addresses bugs in our software systems.
- Collaborated closely with component library users and stakeholders to address their concerns and ensure their needs were met.
- Created comprehensive documentation using Storybook to make our library more straightforward for users.
Technologies: Stencil.js, Web Components, React, Angular, TypeScript, CSS, HTML, Storybook, GitLab, Git, Front-end, HTML5
Software Engineer
2015 - 2019
iTransition
- Participated in creating a web application that enables police departments to manage videos captured on their body-worn cameras.
- Developed a browser tool that enables users to easily redact videos by applying masks to faces, as well as create bookmarks and reports from them.
- Managed a team of three junior developers, providing guidance and support to help them achieve their full potential.
- Implemented unit testing from scratch for the front end, resulting in a 40% reduction in bugs.
Technologies: Knockout (Knockout.js), Angular, jQuery, JavaScript, CSS, HTML, C#, HTML5, Python
Project History
UBS Design System
A design framework used by dozens of teams around the world with various front-end technologies. It provides a unified approach to building digital products and services, with a framework-agnostic design system compatible with Vanilla JavaScript and a React version. The system is designed based on accessibility and usability principles. Also, it is scalable and modular, enabling teams to customize and extend the components according to their specific needs.
Vievu Body Cam
Vievu offers a body camera solution specifically designed for law enforcement agencies. In addition, It is an on-site system that empowers law enforcement agencies with the flexibility to manage their IT and video storage environments. This system enables them to act like redacting, sharing, and compressing video footage as needed.
While working on the solution, I introduced a new feature that enables users to create face masks for their videos directly in the browser. Furthermore, I added the ability to create bookmarks and subtitles for specific video parts.
While working on the solution, I introduced a new feature that enables users to create face masks for their videos directly in the browser. Furthermore, I added the ability to create bookmarks and subtitles for specific video parts.
Rewriting Admin Panel to A Moder React
The project involved completely overhauling an existing admin panel, originally built with AngularJS, and transitioning it to a modern React-based framework. The goal was to modernize the user interface, enhance performance, and simplify the codebase, making it more maintainable and scalable.
Education
2011 - 2015
Bachelor's Degree in Informatics and Applied Mathematics
Belarusian State University - Minsk, Belarus
Skills
Libraries/APIs
React, Node.js, Slack API, jQuery, Handlebars, Drizzle, Vue
Tools
Git, React Apollo, Shadcn, Figma, Atom, GitHub, Mathematica, Stencil.js, GitLab, Shogun, AI SDK, Claude Code
Languages
JavaScript, TypeScript, CSS, HTML, HTML5, GraphQL, C#, Python
Frameworks
Jest, Tailwind CSS, Redux, Next.js, Material UI, Cypress, Angular, Knockout (Knockout.js), React Native
Paradigms
Agile Software Development, Model Context Protocol (MCP)
Platforms
BigCommerce, MacOS, Algolia, Ordergroove, Visual Studio Code (VS Code), Clerk, Vercel
Other
Storybook, Front-end, Styled-components, Artificial Intelligence (AI), Front-end Development, Accessibility, Apollo, Web Components, Informatics, UI Elements, eCommerce, User Interface (UI), User Experience (UX), WebSockets, High-load, LLM Integration, TradingView, Charts, AI-assisted Development, Full-stack, Cursor AI, Agentic AI, AI Development, Web3
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