Code that holds up —
security-first web engineering.
I'm AJ Sabbir, a full-stack developer and security researcher from Rajshahi, Bangladesh. For 8+ years I've built, hardened, and repaired web applications for clients across the globe — from decoding legacy systems to shipping modern, production-ready platforms.
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Engineering discipline,
rooted in curiosity.
I've spent the last 8+ years working at the intersection of software development and security — building applications, then trying to break them, then building them better. That loop is what shapes everything I ship.
Alongside client work, I'm completing a BSc (Honours) in History at the University of Rajshahi — a discipline that's taught me to read systems (and codebases) as artifacts with context, not just syntax to execute.
Read my full storyBased in
Rajshahi, Bangladesh
Education
BSc (Hons) History, in progress
Languages
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Years of Experience
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Projects Completed
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Countries Served
What I can do for you
From reverse-engineering a stubborn legacy bug to hardening a production app against real threats — here's where I add the most value.
Decoding & Debugging
Reverse engineering obfuscated code, decoding proprietary formats, and fixing the deep, hard-to-trace bugs in existing codebases. Legacy system recovery is a specialty, not an afterthought.
Security Auditing & Pen Testing
Network security inspection, vulnerability assessment, and secure application review to find weaknesses before someone else does.
Security Hardening
Security built into development from day one — secure coding practices, not a bolted-on afterthought before launch.
Full-Stack Development
Custom web applications, PHP/MySQL backends, and modern Next.js/Tailwind frontends.
E-commerce Solutions
Online stores, marketplace platforms, payment integration, and admin dashboards.
Web Design
Modern, responsive UI/UX design for business and personal websites.
Digital Marketing Strategy
SEO, growth strategy, and marketing consulting for businesses going online.
International Client Services
Remote collaboration across time zones with global, non-local clients.
Technology I work with daily
Backend
- PHP
- MySQL
- API Development
Frontend
- Next.js
- React
- Tailwind CSS
- JavaScript
Security
- Network Security Inspection
- Reverse Engineering
- Vulnerability Assessment / Pen Testing
- Secure Coding Practices
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Featured Projects
E-commerce
SecurePay Marketplace Platform
A multi-vendor marketplace with integrated payments, vendor dashboards, and fraud-resistant checkout.
Debugging & Decoding
Legacy Codebase Recovery — Inventory System
Reverse-engineered an undocumented 10-year-old inventory system after the original developer became unreachable.
Security
Network Security Audit — Regional Fintech
Full vulnerability assessment and penetration test for a regional fintech handling customer financial data.
Web Development
Next.js Portfolio Platform for Creative Agency
A fast, animated portfolio and case-study platform built with Next.js, React, and Tailwind CSS.
Reverse engineering & security, deeper than most developers go.
Most developers write code forward. I also read it backward — decompiling, decoding, and tracing execution paths to understand systems that ship with no documentation, obfuscated logic, or an original author long gone.
That same instinct — assume it can break, then prove it can't — is what I bring to every security engagement: inspecting network traffic and configurations, probing applications for real exploitable weaknesses, and reviewing code for the mistakes that turn into breaches.
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SQL Injection
Mitigated — prepared statements
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XSS
Mitigated — output encoding
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Auth Bypass
Mitigated — session hardening
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CSRF
Mitigated — token verification
Online Stores
Full storefront builds, ready to sell.
Payment Integration
Secure, reliable checkout flows.
Growth & SEO Strategy
Marketing consulting for businesses moving online — search visibility, conversion-minded structure, and a roadmap for growth.
E-commerce & marketing, built to convert
Beyond code, I help businesses actually launch and grow online — building marketplace platforms and online stores with secure payment integration and admin dashboards that make day-to-day operations simple.
I pair that with practical SEO and growth strategy consulting, so the platform doesn't just work — it gets found and gets used.
See business solutionsWhat clients say
“AJ fixed a bug in our checkout flow that two other developers couldn't figure out. Turned out to be a subtle race condition — he found it, explained it clearly, and fixed it same day. Genuinely impressive debugging skill.”
Daniel R.
Founder, E-commerce Startup (USA)
“We hired AJ for a security audit before our compliance review and he found things our internal team had missed. Clear reporting, professional communication, delivered ahead of schedule.”
Sophie M.
Product Manager (Germany)
“Rebuilt our old WordPress site from scratch — faster, more secure, and easier for my team to update. Communication across time zones was never an issue. Highly recommend for anyone needing real technical depth.”
Ahsan K.
Business Owner (UAE)
How a project comes together
Consultation
Understand your goals, constraints, and what "done" looks like.
Planning
Architecture, scope, and a realistic timeline before writing code.
Development
Iterative builds with regular check-ins, not a black box.
Testing & Security Review
Functional QA plus a security pass — every project, no exceptions.
Delivery
Deployment, documentation, and support after handoff.
Have a project in mind?
Whether it's a stubborn bug, a security review, or a full build from scratch — let's talk about what you need.
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