You will get Expert MERN Stack Developer | React | Node.js | MongoDB Full-Stack Apps
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As an Expert MERN Stack Developer, I specialize in building full-stack web applications using MongoDB, Express.js, React.js, and Node.js. With deep knowledge of JavaScript, REST APIs, and React frameworks like Next.js and Redux, I deliver high-performance web apps tailored to your business goals. Whether you're starting from scratch, need bug fixes, or want to scale an existing project, I offer custom solutions with clean architecture and fully responsive design. I’ve developed admin dashboards, SaaS platforms, eCommerce systems, and real-time apps with seamless backend integrations and database management. Every project is developed with scalable, secure, and maintainable code using modern tech stacks. I follow Agile workflows and provide clear communication, version control (Git), and deployment via Vercel, Heroku, or VPS. Let’s bring your product to life with robust MERN stack engineering and full-stack functionality that performs.
Programming Languages
JavaScript, Python, TypeScriptCoding Expertise
Cross Browser & Device Compatibility, Localization, Performance OptimizationWhat's included $500
These options are included with the project scope.
$500
- Delivery Time 2 days
- Number of Revisions 0
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SR
Steven R.
Dec 3, 2025
Instagram Api Clean up
Rovshen is very patient and understanding.
MM
MK M.
Sep 25, 2025
Ionic + Angular Developer for RevenueCat & Stripe Integration
We had a great experience working with Rovshen. He successfully implemented the payment system in our app with excellent attention to detail and clear communication throughout the process. He was professional, reliable, and delivered the work on time. We’re very satisfied with the results and would gladly work with him again on future projects. Highly recommended!
About Rovshen
8+Yrs | AI SaaS Engineer & Ex-CTO | Your Long term Technical Partner
100%
Job Success
Kings County, United States - 12:35 pm local time
from LLM architecture to production UI you're in the right place.
I'm a Senior AI Full Stack Engineer with 8+ years of experience designing and shipping
systems that combine deep AI backends with polished, performant frontends.
My stack: Python (FastAPI, Django) · Node.js · Next.js · TypeScript · React ·
LangChain · LangGraph · OpenAI · Claude · Pinecone · PostgreSQL · AWS
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WHAT I BUILD
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→ AI Full Stack Applications
Next.js + Python backends with real-time LLM streaming, auth, and multi-tenancy
→ RAG & Knowledge Systems
Hybrid retrieval (dense + sparse), reranking, embedding optimization, citations
→ Agentic AI Systems
Tool-calling agents with memory, orchestration layers, and reflection loops
→ Scalable API Backends
FastAPI / Node.js microservices, async pipelines, RBAC, REST & GraphQL
→ Compliant Enterprise AI
HIPAA-ready healthcare AI, FinTech-grade secure backends
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PRODUCTION SYSTEMS I'VE SHIPPED
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✔ AI clinical documentation agent — HIPAA-compliant, EHR-integrated, in active use
✔ Enterprise RAG platform — hybrid search over structured + unstructured data at scale
✔ AI SEO intelligence SaaS — semantic analysis across billions of documents
✔ Geospatial risk engine — PostGIS + H3 + real-time scoring for PropTech client
✔ Autonomous ingestion agents — schema drift detection, background orchestration
✔ AI marketing SaaS — website and campaign generation from natural language prompts
✔ Secure multi-tenant SaaS — role-based access, audit logging, enterprise deployment
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FULL STACK AI — WHAT THAT MEANS
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Most AI engineers can't build the frontend.
Most frontend engineers can't architect the AI layer.
I do both — and I connect them cleanly:
- Python AI backend → FastAPI / LangGraph / async inference pipelines
- Node.js middleware → BFF layers, webhooks, queue workers, integrations
- Next.js frontend → Server components, streaming UI, real-time AI interfaces
- Vector + Relational DB → Pinecone, PostgreSQL, Redis, Elasticsearch
- Cloud → AWS (EC2, Lambda, S3, RDS), Docker, Kubernetes, CI/CD
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HOW I WORK
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I don't prototype and disappear. I take projects through:
Architecture → MVP → Production Hardening → Monitoring → Scale
You get: clean documentation, maintainable code, and a partner who communicates clearly
and moves fast.
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LET'S WORK TOGETHER
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Send me:
- What you're building
- Your timeline and budget
I'll respond within 24 hours and tell you exactly how I'd approach it.
Core Stack
Next.js Developer, Python, Node.js, TypeScript, React, FastAPI Developer, Django, Express.js
AI & LLMs
LLM Application Development, LangChain Developer, LangGraph, RAG Engineer, AI Agent Architect, Prompt Engineering, Multi-Agent Systems, Fine-Tuning (LoRA/QLoRA), LLM Evaluation, Generative AI, OpenAI API, Claude API, Gemini API
Data & Search
Retrieval-Augmented Generation, Vector Database, Pinecone, Weaviate, Milvus, Semantic Search, Hybrid Search, Elasticsearch, PostgreSQL pgvector
Backend & Infra
REST API, GraphQL, Microservices, Serverless, AWS (Lambda, EC2, S3), Docker, Kubernetes, CI/CD, Async Python, Queue Workers (Celery, Bull)
Domains & Compliance
HIPAA-Compliant Developer, Healthcare AI (HealthTech), FinTech Backend, SaaS Architecture, Multi-Tenant Systems, SOC2, Role-Based Access Control (RBAC)
Long-Tail Phrases
"tool-calling agents with memory", "hybrid dense and sparse retrieval", "real-time LLM streaming", "EHR-integrated AI", "autonomous ingestion agents", "production AI systems"
Steps for completing your project
After purchasing the project, send requirements so Rovshen can start the project.
Delivery time starts when Rovshen receives requirements from you.
Rovshen works on your project following the steps below.
Revisions may occur after the delivery date.
Gather project requirements and assets
Review client requirements, reference links, and design files. Clarify scope and technical needs for React, Node.js, MongoDB, and Express.js.
Set up full MERN stack project
Initialize the codebase with React frontend, Node.js backend, MongoDB, and API routes. Set up folder structure and install dependencies.