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FULL-STACK DEVELOPER · 15+ YEARS

Most developers
write code. I build
competitive advantages.

Delivering complex WordPress platforms, AI-driven automation, precision algorithmic trading systems, and enterprise-grade Python workflows for global businesses.

WordPress & WooCommerce AI & LLM Integration Algorithmic Trading Python & Automation Full-Stack PHP
 Start a Project  4.9 Star · 138 Reviews
15+YEARS ACTIVE
138VERIFIED REVIEWS
4.9★AVERAGE RATING
30+INDUSTRIES SERVED
Raj Kumar Das — Senior Full-Stack Developer
Raj Kumar Das
SENIOR FULL-STACK DEVELOPER · KOLKATA, INDIA
Client Rating
★★★★★ 4.9 / 5.0
Experience
 15+ Years
Status
 Available Now
The Technology Stack

Built for scale.
Engineered for precision.

Applying 15 years of global engineering experience to replace manual bottlenecks with high-performance web platforms, automated workflows, and quantitative trading systems.

WordPress & WooCommerce
Custom plugin architecture, theme development, complex WooCommerce extensions, and multi-site configurations that scale.
PHP MySQL WP REST API WooCommerce
AI & LLM Integration
Building intelligent automation pipelines with GPT, Claude, and custom LLMs for business process optimization and content workflows.
OpenAI API n8n LangChain Automation
Algorithmic Trading
High-precision TradingView indicators, PineScript strategies, and automated signal systems for NSE and global markets.
PineScript TradingView NSE Backtesting
Python & Automation
Custom bots, web scrapers, API integrations, and workflow automation scripts that eliminate manual bottlenecks and save thousands of hours.
Python n8n Bots APIs
Full-Stack PHP Development
REST APIs, custom web apps, MVC frameworks, database architecture.
Payment & API Integrations
Stripe, PayPal, SOAP/REST APIs, third-party SaaS connectors.
Performance & Optimization
Site speed optimization, database tuning, server configuration.
Shipped to Production

From raw requirements to
scalable infrastructure.

A cross-section of high-performance deployments spanning 15 years. Demonstrating deep technical execution across quantitative trading, intelligent automation, and full-stack web platforms.

# Category Architecture & Scope Client Impact
01PINESCRIPTEasyLanguage to PineScript v5 Algorithmic ConversionDaniel S. (USA)Fully Automated Execution
02WORDPRESSSecurity Architecture & Plugin RebuildJuri Livio R. (EU)Enterprise-Grade Security
03API / PAYMENTStripe + SOAP API Asset Validation PlatformRuth S. (AUS)Real-Time Asset Sync
04AUTOMATIONCloud Data Pipeline (WPForms to Dropbox)Will A. (USA)15+ Hours Saved Weekly
05WOOCOMMERCECustom Commission Routing ArchitectureCyrill H. (USA)Zero-Touch Payouts
06FULL-STACKCustom Booking Engine ArchitectureFergus W. (UK)High-Concurrency Scale
07WORDPRESSMultisite Transactional Mail SystemAlex C. (EU)Centralized Delivery
08E-COMMERCECustom EDD Platform Architecture & Plugin SuiteCarl S. (USA)End-to-End Architecture
09AI / LLMChatGPT API Content Generation WorkflowEmanuele P. (EU)10x Output Scalability
10FULL-STACKRich Media Profile System ArchitectureFrancis D. (USA)Optimized Media Flow
11API INTEGRATIONLive Stock Market API Sync SystemFergus W. (UK)<100ms Data Latency
12WOOCOMMERCEComplex E-Commerce Logic CustomizationHemant T. (IN)Bespoke Checkout Logic
13BACKEND / PHPAutomated PDF Generation ArchitectureDanny T. (EU)Zero-Touch Processing
14API INTEGRATIONHigh-Performance API Integration OptimizationAlvaro G. (EU)Sub-100ms Latency
15WORDPRESSBespoke WordPress Theme ArchitectureDaniel F. (EU)Optimized Performance
16FULL-STACKPixel-Perfect Frontend & Backend ArchitectureLennart F. (EU)Precision Execution
17WORDPRESSComplex Issue Resolution & ArchitectureEduardo M. (EU)Rapid Deployment
18PLUGIN DEVCustom Core Plugin Functionality ExtensionJianfe L. (US)Seamless Scalability
19WORDPRESSMultisite Registration Flow ArchitectureJuris K. (EU)Centralized Onboarding
20PLUGIN DEVCustom WordPress Plugin DevelopmentSheryl R. (USA)End-to-End Build
21FRONTENDTheme Core Customization & Logic OverrideIdweurope W. (EU)Pixel-Perfect UI
22PINESCRIPTCustom TradingView Strategy ProgrammingJoshua T. (USA)Live Algorithmic Deployment
23DATA PIPELINEAutomated WooCommerce Booking Data PipelineFergus W. (UK)Seamless ERP Sync
ALL ARCHIVE 1,000+ additional global deployments and proprietary systems. Request Walkthrough ↗
Raj Kumar Das
15+
YRS EXPERIENCE
4.9★
STAR RATING
138
CLIENT REVIEWS
30+
INDUSTRIES
The Execution Standard
  • 24-hour communication SLA — always
  • Architecture locked before execution begins
  • Deadlines are absolute commitments
  • Clean, documented, maintainable code
  • Security-first across every build
  • Managed deployment with dedicated post-launch monitoring
The Story Behind the Code

I don't write code.
I build digital assets.

Over the last 15 years, my focus has remained singular: transforming deeply complex technical requirements into seamless, high-performance systems. I don't just build software; I engineer infrastructure that gives my clients a distinct operational advantage.

Today, I deploy production environments for businesses across four continents. Whether it is a high-volume e-commerce platform processing thousands of transactions, an AI pipeline automating enterprise workflows, or quantitative PineScript models executing live algorithmic trades, I build systems designed for scale, stability, and absolute precision.

Global businesses don't partner with me just to close development tickets. They hire me to eliminate technical bottlenecks and mitigate risk. I treat every deployment as a core business asset, engineering it with the foresight and rigor required for long-term production.

Questions before assumptions — I map scope precisely so nothing surfaces mid-project as a surprise costing you time and money.
Plain language updates — you always know where your project stands, without needing a technical degree to follow along.
Outcome-Driven Engineering — I look at how the technology serves your actual goals. If there’s a smarter, more efficient way to get your desired result, I’ll bring it to the table.
Security-first architecture — Whether it's custom plugin logic or API integrations, data security is built into the foundation, never treated as an afterthought.
Schedule a Technical Consultation →
Technology Stack

Built on 15 years of
real-world delivery.

I do not pad my stack with experimental buzzwords. Every technology listed here has been actively deployed, scaled, and maintained in live, high-stakes business environments.

CMS & E-Commerce
WordPress WooCommerce Shopify Opencart Joomla PHP 8+ MySQL REST API Payment API
AI, Automation & Trading
Python 3 PineScript v6 OpenAI API Claude API LangChain n8n Selenium TradingView Zapier
Frontend, APIs & Infrastructure
JavaScript ES6+ Bootstrap 5 CSS3 / Sass REST APIs SOAP / XML Stripe PayPal Linux VPS Nginx / Apache Git Dropbox API Google APIs Security Audits PDF Generation
Client Reviews

Real feedback from 138 verified clients across the globe

Trusted by entrepreneurs, agencies, and enterprises across four continents — verified reviews from over a decade of delivery.

“
What can I say? He did a job above our expectations. Everything was in line with WordPress’s highest security standards and best practices. An exceptional developer who truly understands his craft.
JL
Juri Livio R.
Cam Aggregator Plugin Fix
★★★★★
★★★★★
Fantastic to work with — clearly knows his stuff. He goes above and beyond to help and deliver quality. Super happy with the end product. Looking forward to working with him again.
Ruth S.
Stripe + SOAP API · Australia
★★★★★
Definitely the most professional and efficient freelancer I’ve found on this platform. Delivered a perfect, smooth result. Would hire again without a second thought. Thank you!
Alex C.
WP Multisite Custom Activation ·
★★★★★
Ron shines. Very professional, clear in his communications, and most importantly committed to the successful completion of whatever project he takes on. Highly, highly recommended.
Sebastian G.
WordPress / Gravity Forms ·
★★★★★
Raj was great. Met all my needs on time and took the time to explain every step he took so I understood the logic. Very happy with his work and communication. Would highly recommend.
Will A.
WPForms to Dropbox Automation ·
★★★★★
Raj was able to turn my fairly complicated TradingView idea into reality. I will definitely use him for any further PineScript scripts I need written. Exceptional work.
Joshua T.
PineScript TradingView Development ·
★★★★★
Excellent work from Ron — always going the extra mile. The delivery was top quality; the API Stock System integration transformed how our client manages inventory. Highly recommended.
Fergus W.
API Stock Integration WP · UK
4.9/5.0
AVG RATING
138
VERIFIED REVIEWS
70%+
REPEAT HIRE RATE
4
CONTINENTS SERVED
Industries Served

Diverse markets.
Cross-sector execution.

15 years of domain breadth means I understand your business context — not just the technology.

E-Commerce & Retail
Finance & Trading
Health & Wellness
Law & Legal Services
Online Education
Restaurants & Food
Photography & Events
Travel & Adventure
Fashion & Lifestyle
Construction & Property
Logistics & Courier
Social & Community
Nursery & Horticulture
Stripe & Payment Systems
Wine & Luxury Goods
Non-Profit & Charity
AI-Powered Automation
Booking & Reservations
Automotive & Parts
Real Estate & Rental
Insurance & Finance
Media & Entertainment
How I Execute

Engineered for precision.
Built for scale.

A transparent, highly refined process built on 15 years of successful deployments. You get consistent, high-signal updates so you always know exactly where your project stands.

STEP 01
Discovery & Scope

I map the exact technical realities of your business. We define complex edge cases, third-party constraints, legacy system limits, and what "ROI" actually looks like for this build. A comprehensive scope is locked before execution begins—eliminating ambiguity, scope creep, and mid-project pivots.

STEP 02
System Architecture

Before any code, I map the data flow, API boundaries, database structure, and plugin dependencies. Problems caught at architecture stage cost minutes. Problems caught in QA cost days. Problems caught in production cost your business. I work at the earliest possible point.

STEP 03
Iterative Delivery

You see working software at every strategic milestone. Each deliverable is functional, rigorously tested, and reviewed before the next architectural stage begins. You maintain absolute visibility and control at every checkpoint—nothing is built in a black box.

STEP 04
Handoff & Support

Clean, well-commented code. A structured walkthrough of what was built and why decisions were made. Documentation you can hand to any future developer. Post-launch support to catch what production reveals that staging missed. This is the standard — not an optional extra.

 CURRENTLY ACCEPTING NEW PROJECTS

Your next project needs
an expert. Not an experiment.

Whether you have a fully scoped brief, a half-formed idea, or a legacy system that needs rescuing — reach out. The first conversation is free, and it will tell you everything you need to know.

 Start the Conversation
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What you can always count on
Response within 24 hours
Scope locked before coding starts
Deadlines treated as commitments
Clean, documented code delivery
Security-first across every build
Post-launch support included