Serob is available for hire
Hire SerobSerob Khurshudyan
Verified Expert in Engineering
Full-stack Engineer and Developer
Yerevan, Armenia
Toptal member since February 9, 2026
Bio
Serob is a senior full-stack engineer specializing in Node.js, TypeScript, and Next.js, with deep experience in payments and applied AI. He has built and maintained Stripe and Chargebee subscription billing (webhooks, 3D Secure, off-session renewals, and dunning) for a SaaS platform and delivered RAG and vector search features for a US real estate platform. Serob owns features end-to-end, from PostgreSQL data modeling to production debugging.
Portfolio
FelixSells.ai LLC
TypeScript, Next.js, Supabase, React, Node.js, Large Language Models (LLMs)...
Software Development Hub
JavaScript, React, Context API, Tailwind CSS, TypeScript, WebSockets, Docker...
AppsGeyser
JavaScript, React, TypeScript, Next.js, Node.js, CSS, HTML, APIs, Full-stack...
Experience
- React - 5 years
- TypeScript - 5 years
- Node.js - 5 years
- NestJS - 4 years
- PostgreSQL - 3 years
- Stripe - 3 years
- Next.js - 3 years
- RAG Systems - 1 year
Work Experience
Full-stack Developer (Next.js)
2026 - 2026
FelixSells.ai LLC
- Built a US real estate transaction platform end-to-end in ~3 months as the primary full-stack developer: Next.js front end, Node.js workflow APIs, PostgreSQL data model, 7 third-party integrations, and RAG-powered AI pricing reports.
- Designed RAG with embeddings and vector search over around 1,000 historical transactions, grounding Claude-generated pricing reports in real deal data instead of raw LLM prompts.
- Integrated seven external services (Stripe, Persona, DocuSeal, Twilio Lookup, Slack, Claude API, and Supabase Storage) into one transaction workflow with consistent state across asynchronous events.
- Implemented an 18-step seller onboarding flow covering property details, identity verification, photo uploads, pricing review, e-signing, and activation payment.
- Designed the PostgreSQL/Supabase schema for sellers, listings, transactions, workflow steps, and events, enforcing data isolation with Row-Level Security.
- Built workflow APIs to advance and reopen transaction stages safely, keeping related records consistent when third-party results arrived out of order.
- Implemented Stripe activation payments with signature-verified, idempotent webhook processing tied directly to transaction state.
- Added an AI provider abstraction with usage tracking, making LLM features observable and easy to switch between providers.
- Built an AI assistant on Claude and RAG that retrieves relevant documents for each seller request, drafts listing descriptions, suggests an estimated price, and guides sellers through onboarding.
Technologies: TypeScript, Next.js, Supabase, React, Node.js, Large Language Models (LLMs), APIs, SendGrid API, Stripe API, DocuSign, Docuseal, Redis, BullMQ, Workers, Docker, Microservices, Web App Development, Scalability, Vector Databases, LLM Integration, Retrieval-augmented Generation (RAG), eCommerce, Agentic RAG Systems, RAG Systems, RAG Architecture, Systems Design, Agentic Coding, API Design, Integrations, Responsive UI, AI-assisted Development, AI Chatbots, Chatbots, Twilio API, Codex, ACID, Artificial Intelligence (AI), Automated Testing, Relational Databases, Workflow Automation & System Integration, Pgvector, Vector Search, AI Engineering, Supabase Auth, Full-stack, Shadcn UI, Tailwind UI, Email Integration, Vercel
Senior Front-end Developer
2025 - 2026
Software Development Hub
- Built a pharmacy aggregation platform in React and TypeScript with real-time pricing and availability across 100+ pharmacies and 10,000+ product records.
- Developed WebSocket-driven inventory and pricing tables that update live without page reloads, with filtering, sorting, and pagination over large datasets.
- Improved rendering performance on data-heavy tables by around 30% by restructuring state and component boundaries to eliminate unnecessary re-renders.
- Built medication search and pharmacy comparison flows, letting users find a product and compare price and availability across pharmacies in one view.
- Integrated back-end APIs with consistent loading, empty, and error states, keeping shared state synchronized across screens.
- Supported Jenkins CI/CD pipelines and release validation, catching build failures and regressions before production.
Technologies: JavaScript, React, Context API, Tailwind CSS, TypeScript, WebSockets, Docker, Jenkins, CSS, HTML, APIs, Testing, Vite, Zod, Zod Schema, Modern JavaScript, Web Application Architecture, Authentication, Deployment, React Hooks, REST, Role-based Access Control (RBAC), Jest, GitHub, Software Architecture, Scalable Architecture, Git, SCSS, JSON Web Tokens (JWT), Front-end, User Experience (UX), Quality Assurance (QA), Mixpanel, Minimum Viable Product (MVP), Mobile Design, User Interface (UI), Front-end Development, Design Systems, Front-end Architecture, SaaS, UI Development, End-to-end Implementation (E2E), Figma to React, API Development, NPM, ECMAScript (ES6), Third-party APIs, Auth, Component-based Development, User Roles, Responsive, Responsive Design, Responsive Coding, Multilingual Websites, Sentry, Unit Testing, Application State Management, Authorization, Code Deployment, Data Validation, Secure Coding, RESTFul APIs, RESTful Web Services, Web App Development, Agentic Coding, API Design, Integrations, Responsive UI, Zustand, AI-assisted Development, Playwright, Storybook, Twilio API, Codex, Cursor AI, Shadcn UI, Tailwind UI, Vercel
Senior Full-stack Developer
2024 - 2026
AppsGeyser
- Own back-end and billing work for an app-builder SaaS platform with 10,000+ active subscriptions, built on Node.js, TypeScript, MySQL, Redis, and Stripe/Chargebee.
- Reduced failed subscription renewals by around 10% by reworking 3D Secure handling, off-session payment retries, and Chargebee dunning flows.
- Cut MySQL query times from 2–3 seconds to under 500 ms by optimizing queries and indexes on high-traffic endpoints.
- Ran around 20,000 background jobs per day through Redis and BullMQ, moving long-running operations out of request-response flows with retries and failure handling.
- Built and maintained subscription billing end-to-end: purchases, renewals, Stripe and Chargebee webhooks, and real-time sync of subscription status with premium access.
- Diagnosed production payment failures (authentication_required, issuer declines, and Stripe Radar blocks), separating integration bugs from bank-side issues.
- Resolved production incidents across Node.js services, MySQL replication, NGINX, queues, and external APIs; refactored legacy back-end components without downtime.
Technologies: JavaScript, React, TypeScript, Next.js, Node.js, CSS, HTML, APIs, Full-stack, API Integration, Architecture, Payment APIs, Payment Security, Payments, Webhooks, Stripe API, Figma, Stripe, Full-stack Development, CI/CD Pipelines, Cloudflare, Microservices, Modern JavaScript, REST APIs, Refactoring, AI Integration, Authentication, Deployment, Framer Motion, React Hooks, Performance Optimization, REST, Role-based Access Control (RBAC), React Testing Library, Webpack, GitHub, Agile Software Development, Back-end Architecture, Back-end Development, Software Architecture, Scalable Architecture, Git, Page Speed Optimization, SCSS, MySQL, Search Engine Optimization (SEO), Server-side Rendering (SSR), Static Site Generators, API Management, Back-end, OAuth, full stack JavaScript, API Architecture, Front-end, User Experience (UX), Legacy Code, Data Engineering, Data Modeling, Database Migration, Integration, Multi-tenant SaaS, Quality Assurance (QA), SQL, Large Language Models (LLMs), REST API Architecture, Agentic AI, Mixpanel, Mobile Apps, Minimum Viable Product (MVP), Mobile Design, User Interface (UI), Front-end Development, Migration, Front-end Architecture, SaaS, UI Development, End-to-end Implementation (E2E), Figma to React, API Development, Databases, Contentful, Core Web Vitals, NPM, ECMAScript (ES6), Fintech, JSON REST APIs, PHP, Auth, Component-based Development, Payment Gateways, PayPal, Material UI, Yarn, User Roles, SSG, Dynamic Routing, Responsive, Responsive Design, Responsive Coding, Headless WordPress, GitLab, Code Refactoring, Application State Management, Authorization, Code Deployment, Data Validation, Secure Coding, RESTFul APIs, RESTful Web Services, Google Analytics, SEO Tools, Mobile App Development, Web App Development, Scalability, Firebase, eCommerce, Systems Design, Agentic Coding, API Design, Google Analytics 4 (GA4), Integrations, Responsive UI, AI-assisted Development, Playwright, Storybook, Chatbots, AWS Lambda, Twilio API, Codex, Prisma, ACID, Automated Testing, Relational Databases, AI Engineering, Cursor AI, Tailwind UI, Email Integration, QR Codes, Vercel
Senior Full-stack Developer
2023 - 2024
Gauge Automotive
- Built a vehicle marketplace and live auction platform handling around 5,000 listings and 100+ concurrent auctions, using React, TypeScript, Redux, Node.js, Express.js, and MongoDB.
- Enforced auction integrity on the server, validating auction state and bid eligibility so invalid or late bids could never be accepted from the client.
- Implemented real-time bid and auction updates, keeping vehicle, auction, and user state in sync between client and server during active sessions.
- Developed REST APIs for listings, auctions, bid submission, user activity, and dashboards.
- Improved back-end reliability with input validation, structured error handling, and clear separation of API, business logic, and data layers.
Technologies: React, TypeScript, Redux, Node.js, Express.js, MongoDB, CSS, HTML, APIs, Full-stack, API Integration, Architecture, Payment APIs, Payments, Figma, Full-stack Development, Zod, Zod Schema, Modern JavaScript, REST APIs, Web Application Architecture, Authentication, React Hooks, REST, Role-based Access Control (RBAC), GitHub, Back-end Architecture, Back-end Development, TypeORM, Software Architecture, Amazon EC2, Git, MySQL, API Management, Back-end, JSON Web Tokens (JWT), full stack JavaScript, API Architecture, Front-end, User Experience (UX), Legacy Code, Data Modeling, Database Migration, Integration, Quality Assurance (QA), SQL, REST API Architecture, Mobile Design, User Interface (UI), Front-end Development, Migration, Design Systems, Front-end Architecture, SaaS, UI Development, End-to-end Implementation (E2E), Figma to React, API Development, Databases, Contentful, Core Web Vitals, NPM, ECMAScript (ES6), Third-party APIs, JSON REST APIs, Twilio, CRM, Customer Relationship Management (CRM), Auth, Component-based Development, Payment Gateways, Bitbucket, Material UI, NoSQL, User Roles, Responsive, Responsive Design, Responsive Coding, GitLab, Multilingual Websites, Application State Management, Authorization, Code Deployment, Data Validation, Secure Coding, RESTFul APIs, RESTful Web Services, Web App Development, Monday.com, API Design, Google Analytics 4 (GA4), Responsive UI, ACID, Relational Databases, GraphQL, Tailwind UI
Back-end Nest.js/Node.js Developer
2020 - 2023
Prof It Development Company
- Delivered 4+ client projects end-to-end in an outsourcing company, building Node.js and NestJS back ends from requirements to production support.
- Built REST APIs with authentication, validation, structured error handling, and logging, reused as a common foundation across client projects.
- Designed relational data layers with Prisma and MySQL and optimized slow queries in high-traffic flows.
- Integrated third-party APIs with authentication, rate-limit handling, and retries for reliable production behavior.
- Wrote Jest tests for critical business logic and refactored legacy code into modular services.
- Integrated 3rd-party services and APIs, handling auth, rate limits, retries, and edge cases for reliable production behavior.
- Refactored legacy codebases into cleaner, modular architecture, improving readability, onboarding speed, and long-term scalability.
- Collaborated directly with clients and PMs in an outsourcing environment, delivering predictable timelines across parallel projects.
- Owned full-stack delivery across multiple apps simultaneously, balancing new features, bug fixes, and production support.
Technologies: JavaScript, React, Node.js, NestJS, AWS IAM, Next.js, Full-stack Development, CI/CD Pipelines, Zod, Zod Schema, REST APIs, Refactoring, Web Application Architecture, Authentication, React Hooks, REST, GitHub, Back-end Architecture, Back-end Development, Software Architecture, Git, Page Speed Optimization, Search Engine Optimization (SEO), Server-side Rendering (SSR), Static Site Generators, API Management, Back-end, JSON Web Tokens (JWT), full stack JavaScript, API Architecture, Legacy Code, Data Engineering, Data Modeling, Database Migration, Multi-tenant SaaS, Quality Assurance (QA), SQL, REST API Architecture, Migration, API Development, Databases, NPM, ECMAScript (ES6), JSON REST APIs, Auth, Component-based Development, Payment Gateways, PayPal, User Roles, Multilingual Websites, Code Refactoring, Authorization, Data Validation, Secure Coding, RESTFul APIs, DocumentDB, Amazon DocumentDB, RESTful Web Services, Firebase, Firebase Authentication, API Design, AWS Lambda, Twilio API, Prisma, Amazon DynamoDB, Relational Databases, GraphQL, Supabase Auth
Project History
Production-ready Apple/Google Pay & Stripe Payment System
I built a production-ready Apple Pay integration using Stripe in a Next.js (App Router) application. I implemented secure PaymentIntent handling, domain validation, webhook processing, and proper error management. The solution follows best practices for security, scalability, and clean architecture, ready for real-world SaaS deployment.
Invitify – Invitation & Event Creation Platform
https://invitify.am/I built Invitify as a full-stack platform for creating and managing digital invitations and events. The goal was to make the process simple for users while keeping the system flexible on the back end.
The stack includes Next.js on the front end and NestJS on the back end, with PostgreSQL as the database and AWS for deployment. I designed the API structure, handled data modeling, and built a UI that allows users to generate and preview invitations in real time.
One of the main challenges was keeping the UI responsive while working with dynamic content and templates. I solved this by structuring the front end into reusable components and optimizing data flow between client and server.
Overall, this project reflects how I approach building production-ready SaaS apps, focusing on clean architecture, performance, and user experience.
The stack includes Next.js on the front end and NestJS on the back end, with PostgreSQL as the database and AWS for deployment. I designed the API structure, handled data modeling, and built a UI that allows users to generate and preview invitations in real time.
One of the main challenges was keeping the UI responsive while working with dynamic content and templates. I solved this by structuring the front end into reusable components and optimizing data flow between client and server.
Overall, this project reflects how I approach building production-ready SaaS apps, focusing on clean architecture, performance, and user experience.
YoYo — AI-powered Real Estate CRM & Automation Platform
Designed and built YoYo, a B2B SaaS platform for real estate agencies that combines CRM, property management, lead pipelines, and AI-powered automation. I owned the product and technical architecture end-to-end, including the Next.js dashboard, NestJS back end, PostgreSQL data model, Redis/BullMQ background jobs, authentication, multi-tenant architecture, deployment infrastructure, and AI integrations. The platform supports property sales and rentals, lead qualification, property-to-buyer matching, agency workflows, and automated communication. I also designed the system for scalable agency accounts, asynchronous processing, staging environments, and production-ready deployment using Docker-based infrastructure.
AI MiniApp App Builder
https://github.com/serob111/MiniBuilderAI MiniApp App Builder is a platform that allows users to generate fully functional mobile applications from simple text prompts. Instead of just producing static HTML, the system builds complete app structures with UI, logic, and deployable outputs.
The platform is powered by LLMs and a custom back end that processes user intent, generates production-ready code, and renders live previews inside a mobile frame. Users can instantly test their apps and export them as installable APK files.
I designed and built the system end-to-end, including the AI generation pipeline, back-end architecture, and front-end experience. The focus was on making the first interaction feel magical, while keeping the system scalable and clean under the hood.
The platform is powered by LLMs and a custom back end that processes user intent, generates production-ready code, and renders live previews inside a mobile frame. Users can instantly test their apps and export them as installable APK files.
I designed and built the system end-to-end, including the AI generation pipeline, back-end architecture, and front-end experience. The focus was on making the first interaction feel magical, while keeping the system scalable and clean under the hood.
Education
2018 - 2022
Bachelor's Degree in Finance
Armenian State University of Economics - Yerevan, Armenia
Skills
Libraries/APIs
React, Node.js, Stripe, Zod, Zod Schema, REST APIs, Auth, API Development, OpenAI API, Context API, Socket.IO, Stripe API, Framer Motion, React Testing Library, Google Maps, Google Maps API, Playwright, Twilio API, PostgREST, Facebook API, Instagram API, Claude API, SendGrid API
Tools
Figma, Git, Claude, Claude Code, NPM, GitLab, Codex, GitHub, Prisma, AWS IAM, Webpack, Bitbucket, Sentry, Google Analytics, Firebase Authentication, Capacitor, Shadcn UI, Jenkins, Expo
Languages
JavaScript, TypeScript, GraphQL, CSS, HTML, Modern JavaScript, SCSS, SQL, ECMAScript (ES6), PHP
Frameworks
Next.js, Express.js, Jest, JSON Web Tokens (JWT), Material UI, Yarn, Tailwind CSS, Redux, NestJS, Fastify, i18next
Paradigms
Microservices, Refactoring, Web Application Architecture, REST, Role-based Access Control (RBAC), Back-end Architecture, Search Engine Optimization (SEO), API Architecture, REST API Architecture, Mobile Design, Component-based Development, Responsive, Responsive Coding, Unit Testing, Testing, Agile Software Development, Code Refactoring, B2B, ACID, Automated Testing
Platforms
Firebase, Mixpanel, Docker, Amazon Web Services (AWS), Amazon EC2, Contentful, Twilio, AWS Lambda, Vercel
Storage
MySQL, Database Migration, Databases, Data Validation, MongoDB, PostgreSQL, Redis, Amazon S3 (AWS S3), NoSQL, Data Pipelines, Amazon DynamoDB, Relational Databases
Other
APIs, Full-stack, API Integration, Vite, Full-stack Development, Artificial Intelligence (AI), Apple Pay, Google Pay, AI Integration, Authentication, Deployment, React Hooks, Performance Optimization, Back-end Development, TypeORM, Software Architecture, OpenAI, Page Speed Optimization, Server-side Rendering (SSR), Static Site Generators, API Management, Back-end, OAuth, full stack JavaScript, Front-end, User Experience (UX), Legacy Code, Error Handling, Integration, Large Language Models (LLMs), Minimum Viable Product (MVP), User Interface (UI), Front-end Development, Migration, Design Systems, Front-end Architecture, SaaS, UI Development, End-to-end Implementation (E2E), Figma to React, Prompt Engineering, Third-party APIs, JSON REST APIs, User Roles, SSG, Dynamic Routing, Responsive Design, Multilingual Websites, Application State Management, Authorization, RESTFul APIs, Web App Development, Agentic Coding, API Design, Responsive UI, AI-assisted Development, WebSockets, Supabase, Architecture, Payment APIs, Payment Security, Payments, Webhooks, CI/CD Pipelines, Cloudflare, Cursor AI, Firebase Cloud Functions, Scalable Architecture, Data Engineering, Data Modeling, Multi-tenant SaaS, Quality Assurance (QA), Agentic AI, Mobile Apps, Core Web Vitals, Fintech, CRM, Customer Relationship Management (CRM), Payment Gateways, PayPal, Headless WordPress, Code Deployment, Secure Coding, DocumentDB, Amazon DocumentDB, Supabase Auth, RESTful Web Services, SEO Tools, Mobile App Development, Scalability, Vector Databases, LLM Integration, Retrieval-augmented Generation (RAG), eCommerce, Monday.com, Agentic RAG Systems, RAG Systems, RAG Architecture, Systems Design, Google Analytics 4 (GA4), Integrations, Zustand, Storybook, AI Chatbots, Chatbots, Turborepo, Workflow Automation & System Integration, Pgvector, Vector Search, Instagram, AI Engineering, Tailwind UI, Email Integration, QR Codes, Finance, DocuSign, Docuseal, BullMQ, Workers
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