Upwork home
Sign up
Project Catalog
DesignDesign
Video & AudioVideo & Audio
Development & ITDevelopment & IT
MarketingMarketing
Writing & TranslationWriting & Translation
MoreMore

You will get Senior Full-Stack Architecture & Code Audit (React / Node / Angular)

Karen C.Status: Offline
Karen C. Karen C.
4.9
Preview image

Let a pro handle the details

Buy Web Application Programming services from Karen, priced and ready to go.
Karen C.Status: Offline
Karen C. Karen C.
4.9
Preview image

Let a pro handle the details

Buy Web Application Programming services from Karen, priced and ready to go.

Project details

This project is designed for teams that want clear answers, not vague advice.

I provide a senior-level software architecture review and code audit focused on identifying real risks, hidden technical debt, performance bottlenecks, and scalability issues — with practical, prioritized recommendations you can act on immediately.

With 12+ years of experience building and maintaining production systems for startups and enterprises, I review your codebase from an architect’s perspective, not just a syntax or style checklist. I look at structure, data flow, security, performance, maintainability, and long-term impact on your product and team.

You’ll receive a concise written report explaining what’s working, what’s risky, and what to fix first, plus a walkthrough to clarify findings and next steps. The goal is to help you make confident technical decisions — whether you’re preparing for growth, refactoring, onboarding new developers, or reducing operational risk.
Programming Languages
JavaScript, TypeScript
Coding Expertise
Performance Optimization, Security

What's included $750

These options are included with the project scope.

$750
  • Delivery Time 3 days
  • Number of Revisions 1
Optional add-ons You can add these on the next page.
60-minute walkthrough call
+$150
Refactor roadmap & estimates
+$200
Security-focused deep dive
+$250

Frequently asked questions

4.9
30 reviews
100% Complete
(30)
1% Complete
(0)
1% Complete
(0)
1% Complete
(0)
1% Complete
(0)

PT

Paruyr T.
5.00
Jun 1, 2026
Full-Stack SaaS Developer Needed for AI-Powered Jewelry ERP Features Karen did an excellent job on our AI-powered Jewelry ERP features project. He quickly understood the existing SaaS architecture, product workflow, and the specific challenges around using ERP data and product images to generate reliable AI-assisted catalog content.

I would gladly work with Karen again and highly recommend him for full-stack SaaS, AI application, and ERP-related projects.

PT

Paruyr T.
5.00
Apr 15, 2026
Senior AI Engineer for RAG Knowledge Base + AI Marketing Content Platform Karen did an excellent job building our AI-powered RAG knowledge base and marketing content platform. He was fast, reliable, and made strong architectural decisions throughout the project. The system he delivered was practical, well-structured, and production-ready. Communication was clear and proactive, and he consistently showed strong technical judgment with OpenAI, Pinecone, Supabase, and backend workflows. I would gladly work with him again and highly recommend him for AI and SaaS projects.

SM

Stuart M.
4.60
Jul 3, 2017
Web development: mainly Wordpress

GS

Guy S.
4.70
Jun 7, 2016
Looking for Web Development for creating Chrome Extension

GF

Glenn F.
4.45
Jan 21, 2016
Web Pages (x34) - HTML5 & AngularJS Integration (45-60 Hours - Need great design focused attention to detail!) We provided a challenging, technical and very detail oriented role using Angular JS design. Karen performed fairly well with this project and was very responsive and capable. We were frustrated with some of the QA processes, we would definitely use him again.
Karen C.Status: Offline

About Karen

Karen C.Status: Offline
Senior Full-Stack Developer | SaaS, AI Apps, Agents, RAG, Automation
100% Job Success
4.9  (30 reviews)
Ottignies-Louvain-la-Neuve, Belgium - 6:05 am local time
I help startups and enterprises turn complex product ideas into stable, scalable SaaS, AI-powered web apps, and mobile products — with clean architecture, reliable delivery, and no unnecessary technical debt.

I’m a senior software engineer with 12+ years of experience specializing in full-stack solutions . I help teams build, scale, modernize, and optimize high-performance applications with a strong focus on maintainability, reliability, and real business outcomes.

I work across JavaScript/TypeScript and Python, using React, Angular, Node.js/NestJS, FastAPI, PostgreSQL, OpenAI, RAG pipelines, and AI agent workflows.

I’ve delivered products across B2B platforms, FinTech, MedTech, CRM systems, accounting/invoicing software, SaaS dashboards, and hybrid mobile apps using technologies like React, Angular, Vue, Node.js, NestJS, React Native, Ionic, MongoDB, and PostgreSQL.

My current focus is helping businesses integrate AI-powered features into real products — including AI apps, automation workflows, RAG-based systems, AI agents, document intelligence, analytics assistants, and conversational interfaces. I use AI-assisted development where it adds speed, but all architecture, product, and production decisions stay human-driven, tested, and maintainable.

I’m strongest when the project needs more than just coding: understanding the business logic, designing the right architecture, reducing technical risk, and shipping a product that can grow after launch.

I can help with:

* SaaS MVP development
* AI-powered web applications
* RAG and document intelligence systems
* AI agents and automation workflows
* Dashboards, admin panels, and internal tools
* API integrations and third-party systems
* Codebase refactoring and performance optimization
* Hybrid mobile apps with React Native or Ionic

If you need a senior engineer who can move fast without creating a mess, I’d be happy to help turn your idea or existing codebase into a reliable product.

Steps for completing your project

After purchasing the project, send requirements so Karen can start the project.

Delivery time starts when Karen receives requirements from you.

Karen works on your project following the steps below.

Revisions may occur after the delivery date.

Codebase & Architecture Analysis

Review the project structure, architecture decisions, dependencies, and overall code quality to understand current strengths and risks.

Security & Performance Audit

Identify security risks, data handling issues, performance bottlenecks, and scalability limitations using industry best practices.

Review the work, release payment, and leave feedback to Karen.