You will get Expert Codex Developer - OpenAI Codex API & App Integration
Project details
Looking to build next-gen coding tools, automate dev workflows, or integrate AI code generation into your platform? I build custom AI solutions leveraging OpenAI’s flagship models to write, review, and analyze code cleanly and reliably.
What I Can Build For You:
Custom Code Generators: AI tools tailored to your frameworks or internal style guides.
Codebase Q&A (RAG): Secure systems that index your private repos so you can "chat" with your code safely.
Automated Code Reviews: Webhooks to auto-review PRs, flag bugs, and suggest fixes.
Full-Stack AI Apps: Complete web interfaces using modern stacks like Next.js, Node.js, Tailwind CSS, and Neon/Firebase databases.
My Technical Expertise:
AI & LLMs: OpenAI API (GPT-4o), LangChain, Vector Databases, prompt engineering.
Core Dev: TypeScript, JavaScript, Python.
Specialties: Secure data pipelines, handling token limits, and enforcing strict JSON outputs.
I don’t just build basic wrappers; I deliver production-ready, cost-optimized solutions. Please reach out before ordering to discuss your specific infrastructure!
What I Can Build For You:
Custom Code Generators: AI tools tailored to your frameworks or internal style guides.
Codebase Q&A (RAG): Secure systems that index your private repos so you can "chat" with your code safely.
Automated Code Reviews: Webhooks to auto-review PRs, flag bugs, and suggest fixes.
Full-Stack AI Apps: Complete web interfaces using modern stacks like Next.js, Node.js, Tailwind CSS, and Neon/Firebase databases.
My Technical Expertise:
AI & LLMs: OpenAI API (GPT-4o), LangChain, Vector Databases, prompt engineering.
Core Dev: TypeScript, JavaScript, Python.
Specialties: Secure data pipelines, handling token limits, and enforcing strict JSON outputs.
I don’t just build basic wrappers; I deliver production-ready, cost-optimized solutions. Please reach out before ordering to discuss your specific infrastructure!
Programming Languages
JavaScript, Python, TypeScriptCoding Expertise
Cross Browser & Device Compatibility, Performance Optimization, SecurityWhat's included
| Service Tiers |
Starter
$100
|
Standard
$499
|
Advanced
$999
|
|---|---|---|---|
| Delivery Time | 3 days | 5 days | 7 days |
Number of Revisions | 1 | 3 | 5 |
Number of Pages | 3 | 5 | 8 |
Design Customization | - | - | |
Content Upload | - | ||
Responsive Design | |||
Source Code |
Optional add-ons
You can add these on the next page.
Additional Revision
+$50
Additional Page
(+ 1 Day)
+$100
Design Customization
(+ 3 Days)
+$200
Content Upload
(+ 3 Days)
+$200Frequently asked questions
About Nazmul
Full-Stack MERN Developer | React, Next.js, Node.js, MongoDB
Chattogram, Bangladesh - 8:54 am local time
Hi, I’m Nazmul Hasan, a Full-Stack JavaScript Developer with hands-on experience building production-ready MERN and Next.js applications used by 25,000+ monthly active users.
I specialize in turning ideas into fast, scalable, and monetized web platforms — focusing not just on code, but on performance, SEO, and real business results.
💡 What I Do Best
Full-Stack Development
• MERN Stack (React, Next.js, Node.js, Express)
• RESTful APIs & backend architecture
• Authentication (Firebase Auth, JWT)
• Serverless & cost-optimized deployments
Frontend & Performance
• React.js & Next.js (SSR, SEO-friendly)
• Tailwind CSS, responsive UI
• 90+ Google PageSpeed scores
• Progressive Web Apps (PWA)
Databases & Cloud
• MongoDB, PostgreSQL (Neon)
• Firebase & Supabase
• Vercel, Cloudflare R2, Google Cloud
SEO & Monetization
• Technical SEO (ranked #1 for competitive keywords)
• Google AdSense & Mediavine integration
• Analytics & performance tracking
🧪 Proven Experience (Not Theory)
• Built 15+ production applications
• Platforms serving 25,000+ monthly users
• Reduced infrastructure costs by 60% using serverless architecture
• Developed SaaS tools, dashboards, and marketplaces from scratch
• Experience scaling products from 0 → real users
🧩 WordPress (Secondary Skillset)
I also bring strong WordPress experience, which helps when:
• Integrating WordPress with modern stacks
• Optimizing legacy sites for speed & SEO
• Customizing themes, WooCommerce, and plugins
• Migrating WordPress projects to modern architectures
🤝 How I Work
• Clean, maintainable, production-grade code
• Clear communication & honest timelines
• Focus on long-term scalability, not quick hacks
• Product-thinking mindset (engineering + business)
📩 Let’s Talk
If you’re looking for a reliable full-stack developer who understands performance, SEO, and real-world scaling, feel free to message me.
I’m happy to discuss your idea — even if you’re still validating it.
Steps for completing your project
After purchasing the project, send requirements so Nazmul can start the project.
Delivery time starts when Nazmul receives requirements from you.
Nazmul works on your project following the steps below.
Revisions may occur after the delivery date.
Discovery & Architecture Setup
I will review your requirements, analyze your current codebase or workflow, and set up the initial architecture and API connections.
AI Development & Integration
I will build the core AI logic, implement the Codex API, handle prompt engineering, and connect the AI to your specific tools or custom app.