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Raj Halder
— AI / Full Stack Engineer

I'm Raj Halder — a full-stack engineer working across CRM platforms, trading integrations, backend infrastructure, and production applications. I turn complex business requirements into reliable software, from the interface to the underlying systems.

Currently engineering FinTech and trading software at YoForex.

Core:ReactNext.jsTypeScriptNode.jsPostgreSQLMT5
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Raj Halder at work
Production Active

Raj Halder

Software Engineer · YoForex

Domain
FinTech / Trading Platform
Location
Kolkata, India
Education
B.Tech IT '25 (8.15 CGPA)
Flagship AI
DevPilot AI →

Target Roles:AI / Full Stack / SWE

Work Preference:Remote / Hybrid

Engineering Focus Areas

5 core domains

Featured Projects

Production Systems & AI Products

Architected and built across AI, FinTech, and real-time environments. Every project emphasizes clean code, API type safety, and real-world utility.

AI / Full Stack SaaSLive · in development2026

DevPilot AI

AI career co-pilot for developers

The Problem
Developers preparing for jobs juggle separate tools for resume checks, portfolio feedback, interview practice and job search, and rarely learn why an application failed.
What I Built
I designed and built the product end to end: a Next.js 16 app with ten dashboard modules, an Express and TypeScript API over MongoDB, real-time interview sessions over Socket.IO, and AI features on Groq's Llama 3.3 70B.
  • Next.js 16
  • React 19
  • TypeScript
  • Tailwind CSS
  • Node.js
  • Express
  • MongoDB
  • Mongoose
  • +6
Read Case Study: DevPilot AILive Demo: DevPilot AI (opens in a new tab)GitHub: DevPilot AI (opens in a new tab)
FinTech / Real-Time SystemsLive · production2026 — Present

Production FinTech & Trading Systems

Live trading terminal, CRM and real-time market data

Professional FinTech work: the RTX 5 Web Terminal traders use in the browser, CRM and back-office workflows, trading analytics, and real-time market-data integrations.

  • Live: RTX 5 Web Terminal, a browser trading terminal
  • CRM: accounts, KYC, wallets, deposits, withdrawals
  • Production debugging across code, servers and gateways

The trading terminal is public. CRM, back-office and backend code, internal URLs and system details are private and not shown here.

  • React
  • Next.js
  • TypeScript
  • Tailwind CSS
  • Zustand
  • Node.js
  • +9
Read Case Study: Production FinTech & Trading SystemsOpen live terminal: Production FinTech & Trading Systems (opens in a new tab)
AI / Computer VisionLive2026

Aadhaar Mask Detector

Computer-vision API that masks Aadhaar numbers

The Problem
Aadhaar cards are routinely shared as ID proof with the full 12-digit number exposed. Masking it by hand is slow and easy to get wrong.
What I Built
A FastAPI service that runs a YOLOv8 model trained to find the number, masks it with OpenCV and returns the result to a drag-and-drop web client. The API is containerised with Docker and runs on Render; the frontend is on Vercel.
  • Python
  • FastAPI
  • YOLOv8
  • PyTorch
  • OpenCV
  • Tesseract OCR
  • Docker
  • Render
  • +2
Read Case Study: Aadhaar Mask DetectorLive Demo: Aadhaar Mask Detector (opens in a new tab)GitHub: Aadhaar Mask Detector (opens in a new tab)

Developer Tools & Web Applications

Additional Projects

AI code analyzers, WebSockets chat applications, and full-stack MERN systems.

View All Repositories
AI Verse code editor with HTML, CSS and JS tabs and an Explain button
AI / Developer ToolsLive

AI Verse

AI developer tools & code analyzer

A developer tool suite featuring an AI-assisted Monaco code editor with real-time execution, automated AI code explanation, and technical assessment modules.

Problem & Engineering details
Problem
Students and developers switch between separate AI tools to explain code, summarise notes and practise questions.
What I built
Version one is a React app with four AI tools on Gemini 2.0 Flash, PDF input with pdf.js and PDF export with jsPDF. Version two adds a Monaco-based editor with live preview and an Express API that calls Groq's Llama 3.3 70B to explain code.
  • React
  • Vite
  • Gemini API
  • Groq · Llama 3.3 70B
  • +3
Live DemoSourceAPI source
Chatty sign-in screen next to a gradient panel of chat bubbles
Live

Chatty

Real-time chat app

A web messaging app with sign-in and real-time conversations over Socket.IO.

Problem & Engineering details
Problem
Chat needs instant two-way delivery, which request-and-response APIs can only fake with polling.
What I built
A React (Vite) client with authentication and a Socket.IO connection to a backend API hosted on Render.
  • React
  • Vite
  • Socket.IO
  • REST API
  • +2
Live DemoPrivate Source
Drive by Raj home page with the headline Drive your dreams
Live

HaldarCars

Full-stack car marketplace (MERN)

A car buying and selling site with accounts, listings and image uploads.

Problem & Engineering details
Problem
Buyers and sellers need one place to list cars with photos and browse what is for sale.
What I built
A React frontend with an Express and MongoDB API: JWT authentication with Joi validation, buy and sell routes, and image uploads with Multer.
  • React
  • Node.js
  • Express
  • MongoDB
  • +5
Live DemoSource
Fotoflix photo grid with search and favourites
Live

Fotoflix

Photo discovery app on the Unsplash API

Search and browse photography from the Unsplash API, open images in a lightbox and save favourites.

Problem & Engineering details
Problem
Browsing a large photo API needs fast search, a focused viewer and a way to keep what you like.
What I built
A React app with client-side routing, Unsplash API search, a lightbox viewer and favourites stored in localStorage.
  • React
  • React Router
  • Unsplash API
  • localStorage
Live DemoSource

Production Experience

Software Engineer · YoForex

Hands-on full-stack and systems engineering for a high-throughput trading and FinTech platform. Real users, real money movement, and live market infrastructure.

Area 01

FinTech CRM & client applications

  • Developed and maintained CRM functionality for users, trading accounts, KYC, wallets, deposits, withdrawals, transactions and admin workflows.
  • Worked on authentication and OTP verification in client-facing applications and admin panels.
Area 02

Trading interfaces & real-time data

  • Built the frontend of the RTX 5 Web Terminal, a browser trading terminal now live at webterminal.orrnn.com.
  • Built and improved trading-platform interfaces with React, Next.js, TypeScript, Tailwind CSS and reusable UI components.
  • Worked with RTX5/MT5-related infrastructure, broker integrations, market data, tick processing, OHLC candles and multi-timeframe charts.
  • Used FIX 4.4 and WebSockets for live market data and trading-terminal features such as symbol switching and live chart updates.
Area 03

Trading analytics

  • Built trading-journal and analytics features: win rate, profit factor, expectancy, risk-to-reward, maximum drawdown, trade notes, reports, CSV export and Monte Carlo simulation.
Area 04

APIs, data & services

  • Worked with PostgreSQL, Prisma, Redis, REST APIs and WebSockets across CRM, trading and financial workflows.
  • Worked across Rust (Axum, Tokio), C++ (Drogon) and Node.js/TypeScript components in gateway, API and trading-system integrations.
Area 05

Production debugging

  • Debugged production issues involving HTTP 429/502 errors, authentication, WebSockets, PostgreSQL, Nginx, gateway connectivity and environment configuration.
  • Investigated copy-trading execution across the open/close/modify order lifecycle, queues, retries and reconciliation.
Area 06

Technical ownership

  • Coordinate and review technical work across teams, and resolve production issues whose cause can sit in application code, admin code, deployment, servers, routing, integrations or environment configuration.
  • Reviewed a client-trusted security check and pushed for server-side validation and clear trust boundaries.
  • Exploring AI-assisted workflows and automation for day-to-day engineering.

Technical Stack & Architecture

Full Stack, AI & Systems Toolbox

Organized by engineering layer. Practical production experience backing every listed technology.

FrontendLayer 01

Frontend

  • React
  • Next.js
  • TypeScript
  • JavaScript
  • Tailwind CSS
BackendLayer 02

Backend

  • Node.js
  • Express
  • Python
  • FastAPI
DatabaseLayer 03

Database

  • PostgreSQL
  • MongoDB
  • Redis
  • Prisma
SystemsLayer 04

Systems

  • REST APIs
  • WebSockets
  • Socket.IO
  • Authentication (JWT / OAuth)
  • Caching & Queues
  • FIX 4.4
DevOpsLayer 05

DevOps

  • Docker
  • CI/CD
  • Nginx
  • Linux / VPS
  • Vercel / Render
AILayer 06

AI

  • LLM APIs (Groq, Gemini)
  • AI Applications
  • Computer Vision (YOLOv8, OpenCV)
  • PyTorch
  • AI Developer Tools

Also Used in Production

YoForex

Infrastructure and gateway services integration:

  • Rust (Axum, Tokio)
  • C++ (Drogon)
  • RTX5 / MT5 ecosystem

Active Engineering Research

Growth

Currently deepening distributed systems and concurrency:

  • Go
  • Distributed System Design
  • Scalable Real-Time Event Architecture

Practical Domain Experience

Where I've Applied These Technologies

Five concrete operational domains backed by shipping applications and production systems.

AI-powered products

LLM features built into real products, and computer vision where it fits the problem.

  • LLM APIs (Groq, Gemini)
  • YOLOv8
  • OpenCV
  • PyTorch

Production & Project Proof

APIs & real-time systems

REST APIs, WebSocket services and live market data, with authentication and validation built in.

  • Node.js
  • Express
  • FastAPI
  • Socket.IO
  • FIX 4.4

Production & Project Proof

Now

Currently building

What I'm working on at the moment, and the most recent activity on my public repositories.

Exploring

AI-assisted engineering

AI workflows and automation for day-to-day engineering work.

Recent activity on GitHub

46 public repositories · coding in public since 2023

Snapshot
View GitHub profile (opens in a new tab)
Raj Halder engineering workspace
Raj Halder · Software EngineerKolkata, India

About Me

Full Stack Engineer from interface to infrastructure

I'm Raj Halder, a full-stack engineer focused on CRM platforms, fintech applications, and trading-system integrations.

At YoForex, I work across frontend interfaces, backend services, APIs, and production delivery while taking on technical leadership responsibilities.

I enjoy solving problems where business workflows, system reliability, and complex integrations meet.

Location
Kolkata, West Bengal, India
Open to Remote, international, hybrid, or relocation
Education
B.Tech in Information Technology (2025)
Maulana Abul Kalam Azad University of Technology (MAKAUT) · CGPA 8.15
Specialized Training
Python Full Stack Development
QSpiders
Target Roles
CRM & FinTech Engineer, Full Stack Engineer (React / Next.js / Node.js)
FinTech firms, trading platforms, product companies, and international engineering teams

Engineering Methodology

How I Build & Ship

A disciplined engineering loop applied across new feature design, real-time pipelines, and production incident resolution.

01

Understand the Business Problem

Deconstruct requirements into functional specifications, operational edge cases, and compliance boundaries.

02

Design System & Data Flow

Architect schema models, entity relations, and service boundaries with clear trust lines.

03

Build Frontend & Backend

Develop responsive, modular React and Next.js interfaces paired with robust, type-safe APIs in Node.js and Python.

04

Integrate APIs & External Systems

Establish resilient bridges to MetaTrader 5 Manager workflows, Redis Pub/Sub channels, and WebSockets.

05

Test Critical User Workflows

Stress test authentication boundaries, concurrency conflicts, and worst-case failure modes before releasing.

06

Deploy, Monitor & Improve

Containerize with Docker, configure reverse proxies, trace HTTP 429/502 bottlenecks, and continuously refine performance.

Get In Touch

Let's build something useful.

Open to software engineering opportunities, product teams, and interesting technical challenges.

Direct Email

rajhalder.dev@gmail.com
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Email Me (Gmail)LinkedIn (opens in a new tab)GitHub (opens in a new tab)Download Resume

Based in Kolkata, India · Available with Immediate / flexible notice

Send a Message

Reach out regarding engineering openings, technical consulting, or project collaborations. Delivered straight to my Gmail.