Sergej Kurbanov, Developer in Prague, Czech Republic
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Sergej Kurbanov

Verified Expert  in Engineering

Full-stack Developer

Prague, Czech Republic
Toptal Member Since
December 9, 2019

Sergej is a full-stack developer with over seven years of experience building scalable, feature-rich applications, workflow automation, and AI integrations. From coaching 200+ female students in becoming junior React developers over the last four years to building his own AI-driven SaaS product, Sergej's engaging approach and dedication to staying ahead of the curve make him an invaluable asset to any project or team.


Freelance Client
JavaScript, Node.js, Prismic, Google Apps Script, Google API, Slack API...
React, CSS, HTML, JavaScript, Team Leadership, Software Architecture...
Purple Technology
JavaScript, TypeScript, Node.js, React, Amazon Web Services (AWS), AWS Lambda...




Preferred Environment

Node.js, Git, MacOS, Amazon Web Services (AWS)

The most amazing...

...project I've led was implementing an AI-powered influencer marketing search system, reaching 2nd place on Product Hunt's daily ranking.

Work Experience

Full-stack JavaScript Developer

2020 - PRESENT
Freelance Client
  • Developed a user-friendly flow enabling natural language interactions with uploaded PDFs for queries and discussions, integrating Pinecone's vector database, OpenAI embeddings, and LangChain into a React application.
  • Streamlined a company's workflow by simplifying their Google services flow, turning several into more practical and easy-to-use solutions, tools, and integrations.
  • Transformed business ideas into technical solutions. Created products and features that increased productivity, presented new possibilities, and reduced manual processes.
  • Developed a Slack chatbot integrating Google's Dialogflow platform, which resulted in a bot that smoothly leads users through conversations while collecting relevant data points.
  • Built an image processing tool that merges input images with diverse backgrounds, generating Google Slides for swift design prototyping with stakeholders.
  • Developed an interactive Slack workflow for media download, processing hundreds of daily video/audio files with edits and tags for efficient storage.
Technologies: JavaScript, Node.js, Prismic, Google Apps Script, Google API, Slack API, Slackbot, Vue, Dialogflow, ImageMagick, FFmpeg, Backblaze B2, Iconic, Google APIs, Vector Databases, OpenAI GPT-3 API, LangChain, D3.js, Plotly.js, Dashboards, Data Visualization, Full-stack, GraphQL, Back-end, Automation, Content Management Systems (CMS), JSON, Front-end Architecture, Front-end Design, WCAG 2, Video Transcoding

Front-end Lecturer

2020 - PRESENT
  • Lectured at seven 3-month front-end boot camps, teaching and coaching 200+ women to become junior React developers from scratch.
  • Prepared tens of hours of materials and exercises related to front-end technologies, mainly for JavaScript and React.
  • Mentored on multiple final projects, advising on architecture, design, clean code, and technology choices.
Technologies: React, CSS, HTML, JavaScript, Team Leadership, Software Architecture, Architecture, JSON, Functional Programming, Front-end Architecture, Front-end Design, WCAG 2

Senior Full-stack Developer

2023 - 2024
Purple Technology
  • Designed and built a retrieval augmented generation (RAG) pipeline with LangChain, trained on 2,000+ company documents, and integrated into a Slack FAQ bot for instant query responses.
  • Developed comprehensive back-end solutions for a fintech trading application using AWS technologies (Lambda, SNS, SQS, DynamoDB, and Cognito).
  • Utilized serverless technologies to implement a strategic, time-sensitive promotional campaign that significantly increased user engagement and trading activity by over 40%.
  • Implemented a custom Amazon Cognito admin access flow, reducing the support team's time for investigating customer-reported UI bugs by 80%.
Technologies: JavaScript, TypeScript, Node.js, React, Amazon Web Services (AWS), AWS Lambda, Amazon DynamoDB, Amazon Cognito, Amazon Simple Notification Service (Amazon SNS), Amazon Simple Queue Service (SQS), MongoDB, LangChain, Qdrant, Vector Databases, Slack API, Jest, Testing, Front-end, Cypress, AWS DevOps, DevOps, Infrastructure as Code (IaC), Lambda Functions, Lambda Architecture, Serverless, Serverless Architecture, Front-end Architecture, Front-end Design, Playwright, WCAG 2, AI Programming, AI Design, OpenAI GPT-3 API, OpenAI GPT-4 API, AI Integration, AWS Cloud Development Kit (CDK), CI/CD Pipelines, AWS SDK, AWS Step Functions

AI Developer

2023 - 2023
  • Architected and developed AI integration with OpenAI APIs for influencer marketing search, analysis, and grouping, slashing manual search time of our outreach managers by 95%.
  • Led a team of three developers, conducting code reviews and pair programming. Guiding them in best practices and creating an environment to consistently deliver timely, bug-free features.
  • Conducted database migrations in Supabase, optimizing influencer table structure and relations and removing duplicates. This increased overall application performance and allowed the collection of precious analytic data.
  • Developed Jest and Cypress E2E tests focusing on happy paths, significantly reducing and preventing bugs.
Technologies: React, Supabase, PostgreSQL, OpenAI, OpenAI GPT-3 API, Node.js, Cypress, Jest, Testing, Front-end, AI Programming, AI Design, Large Language Models (LLMs), Language Models, Generative Pre-trained Transformers (GPT), Generative Pre-trained Transformer 3 (GPT-3), User Interface (UI), User Experience (UX), Software Development, SQL, Front-end Architecture, Front-end Design, Playwright, WCAG 2, OpenAI GPT-4 API, AI Integration

Full-stack Developer

2023 - 2023
Personal Project
  • Designed and integrated a serverless technology stack using Supabase and Vercel, ensuring performance, reliability, and security for a seamless user experience.
  • Refined an AI-driven app with user testing, leveraging GPT technology to tailor recipes to user preferences and dietary needs, enhancing overall user experience.
  • Designed the application's UI/UX utilizing accessibility best practices. Developed an intuitive and visually appealing design to enhance user experience and ease of use.
  • Developed and executed successful SEO and analytics strategies to enhance the app's visibility and drive traffic. Regularly analyzed page insights and user behavior data to fine-tune marketing efforts.
Technologies: Next.js, Supabase, OpenAI, React, Tailwind CSS, TypeScript, Stripe, OpenAI GPT-3 API, Architecture, OpenAI GPT-4 API, Software Architecture, ChatGPT, Python, Artificial Intelligence (AI), Pinecone, PostgreSQL, Generative Pre-trained Transformers (GPT), APIs, Cloudflare, Prisma, Back-end, JSON, SQL, Front-end Architecture, Front-end Design, Strapi, AI Design, AI Programming, AI Integration, Stripe API, CI/CD Pipelines

Full-stack Web Developer

2018 - 2020
DEVIX Technologies s.r.o
  • Developed a CMS for concurrent uploading and managing video files such as movies or TV show episodes and daily saving hours of users' time.
  • Implemented and integrated a custom action tracking tool for an online store, allowing the company to collect and analyze user activity.
  • Built an extensive, component-based mailing application similar to Mailchimp for marketing messages with live preview and staging.
  • Redesigned and rewrote a price and product comparing platform utilizing SSR and custom drag-and-drop Vue components. Tens of thousands of users use the site.
  • Created a CMS for managing the company's invoices and employees using React and GraphQL.
Technologies: NPM, jQuery, Quasar, Vuex, MongoDB, Express.js, CSS, Git, Scrum, Agile, Node.js, JavaScript, SCSS, HTML5, Vue, Trello, Firebase, Material UI, Single-page Applications (SPA), REST, RESTful Services, Back-end, Webpack, Confluence, JSON, Mongoose, REST APIs, Storybook, Front-end Architecture, Front-end Design, WCAG 2, CI/CD Pipelines

Full-stack Web Developer

2016 - 2018
  • Created a custom responsive drag-and-drop tool in React—connecting calendar, note, and appointment functions and saving users from using multiple applications.
  • Implemented a car location tracking system that calculates potential banner revenue based on impressions for a React Native application.
  • Supervised and trained a team of two front-end interns.
  • Developed precise airspace tracking of drones, processing their attributes such as height, atmospheric pressure, or tilt for a web application.
  • Created a secure flight scheduling application for pilots with a custom calendar component.
Technologies: NPM, React Router, CSS, Git, React Native, MongoDB, Express.js, Node.js, jQuery, JavaScript, SCSS, HTML5, Redux, React, Front-end Development, Full-stack Development, Microservices, Shopify, Toolkits, REST, RESTful Services, Back-end, Webpack, JSON, Mongoose, REST APIs, Front-end Architecture, Front-end Design

Recipe Smarter
An AI-powered app for generating personalized recipes and meal plans to fit users' dietary needs and preferences. I was the solo developer, bringing the app from conception to launch with all the bells and whistles.

Custom Emailing CMS for an eCommerce Company

A complete content management system (CMS) that allowed for filtering, sorting, and organizing marketing messages for easy management and analysis that successfully reduced emailing costs by over 90%.

Developed a component-based marketing email application that utilized Vue and Quasar for easy customization and scalability, closely working with a team consisting of a PO, designer, two back-end developers, and QAs.

Integrated the mailing application into the company's existing system and database, ensuring seamless communication between different components of the system.

Public Facing Website for an Advertising Company

Rewrote and redesigned a project in Vue, improving the website's responsiveness and speed by over 50% and increasing mobile usage by over 100%.

Integrated and managed the website's back end using Prismic, a headless CMS, to enable easy content management and updates.

Developed custom responsive components to ensure the optimal layout and scalability of the website on different devices and screen sizes. Optimized for page speed and SEO, which resulted in improved search engine rankings and increased traffic to the website.

Integrated several third-party APIs (such as HiBob) and implemented Gmail authentication to enhance the website's functionality and user experience.

Q&A and Video Ingestion Slack Bot

Developed and deployed a custom Slack bot that utilizes Google's Dialogflow to provide users with a Q&A channel and form-based media processing capabilities.

Utilized media downloading libraries and FFmpeg to programmatically download videos and apply user-defined edits and parameters, resulting in an over 10x increase in productivity for the creative team.

Integrated with Iconik, a cloud-based content management system, to seamlessly upload processed media and eliminate the need for manual asset management.
2015 - 2019

Bachelor's Degree in Computer and Information Science

Czech Technical University - Prague, Czech Republic


React, Vue, Node.js, Redux-Saga, React Router, Vuex, jQuery, REST APIs, Slack API, Google API, Google APIs, Stripe, Plotly.js, D3.js, Playwright, Stripe API, ImageMagick, FFmpeg


NPM, Slack, Git, Trello, Dialogflow, Create React App, Redux Thunk, Mongoose, ChatGPT, Prisma, AWS Cloud Development Kit (CDK), AWS SDK, AWS Step Functions, Jira, Confluence, Webpack, GitLab, Amazon Cognito, Amazon Simple Notification Service (Amazon SNS), Amazon Simple Queue Service (SQS)


Express.js, Redux, Next.js, Tailwind CSS, Jest, Cypress, Material UI, Quasar, React Native, JSON Web Tokens (JWT)


HTML, JavaScript, HTML5, CSS, SCSS, ES8, TypeScript, SQL, GraphQL, Google Apps Script, ECMAScript (ES6), Python


REST, Testing, Scrum, Agile, Functional Programming, Automation, Microservices, Lambda Architecture, Serverless Architecture, DevOps


Netlify, MacOS, Firebase, AWS Lambda, Amazon Web Services (AWS), Docker, Visual Studio Code (VS Code), Shopify


MongoDB, JSON, PostgreSQL, Backblaze B2, Amazon DynamoDB


Software Development, OpenAI GPT-3 API, OpenAI GPT-4 API, Architecture, Software Architecture, Full-stack Development, Front-end Development, Single-page Applications (SPA), Data Visualization, Full-stack, Back-end, RESTful Services, Front-end, Front-end Architecture, Front-end Design, WCAG 2, Gatsby, Communication, APIs, Styled-components, Supabase, OpenAI, Generative Pre-trained Transformers (GPT), LangChain, Team Leadership, Dashboards, Serverless, Lambda Functions, Infrastructure as Code (IaC), Generative Pre-trained Transformer 3 (GPT-3), AI Design, Language Models, Large Language Models (LLMs), AI Programming, AWS DevOps, Storybook, Strapi, AI Integration, CI/CD Pipelines, Content Management Systems (CMS), User Experience (UX), User Interface (UI), Prismic, Slackbot, Iconic, Computer Science, Information Science, Image Processing, Vector Databases, Pinecone, Artificial Intelligence (AI), Cloudflare, Toolkits, Qdrant, Video Transcoding

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