You will get your existing MERN stack application fixed, refactored and optimised
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Project details
Is your MERN stack application broken, slow, or full of technical debt? I fix that.
I'm a Full Stack Developer with 5+ years debugging and refactoring production React, Node.js, Express, and MongoDB applications. I've rescued SaaS products with tangled APIs, healthcare apps with broken UIs, and dashboards that crashed under real user load.
WHAT I'LL FIX:
✓ Frontend bugs — broken layouts, state issues, render problems
✓ Backend bugs — API errors, authentication issues, database problems
✓ Performance issues — slow load times, unoptimized queries, bundle bloat
✓ Responsiveness across devices and browsers
✓ Code quality — refactoring messy components, untangling logic
WHO THIS IS FOR:
→ Teams whose MERN app has bugs they can't track down
→ Startups inheriting a codebase from a previous developer
→ Founders whose app worked at 10 users but breaks at 1000
WHY ME:
→ 100% Job Success
→ 5+ years rescuing production MERN codebases
→ I find the root cause, not just the symptom
→ Every fix is tested and documented before delivery
Send me your repo or describe the issues, I'll review and confirm the scope before we start.
I'm a Full Stack Developer with 5+ years debugging and refactoring production React, Node.js, Express, and MongoDB applications. I've rescued SaaS products with tangled APIs, healthcare apps with broken UIs, and dashboards that crashed under real user load.
WHAT I'LL FIX:
✓ Frontend bugs — broken layouts, state issues, render problems
✓ Backend bugs — API errors, authentication issues, database problems
✓ Performance issues — slow load times, unoptimized queries, bundle bloat
✓ Responsiveness across devices and browsers
✓ Code quality — refactoring messy components, untangling logic
WHO THIS IS FOR:
→ Teams whose MERN app has bugs they can't track down
→ Startups inheriting a codebase from a previous developer
→ Founders whose app worked at 10 users but breaks at 1000
WHY ME:
→ 100% Job Success
→ 5+ years rescuing production MERN codebases
→ I find the root cause, not just the symptom
→ Every fix is tested and documented before delivery
Send me your repo or describe the issues, I'll review and confirm the scope before we start.
Programming Languages
HTML & CSS, JavaScript, TypeScriptCoding Expertise
Cross Browser & Device Compatibility, Performance Optimization, DesignWhat's included
| Service Tiers |
Starter
$49
|
Standard
$99
|
Advanced
$499
|
|---|---|---|---|
| Delivery Time | 3 days | 7 days | 14 days |
Number of Revisions | 1 | 2 | 3 |
Design Customization | - | - | - |
Content Upload | - | - | - |
Responsive Design | - | - | - |
Source Code |
Frequently asked questions
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RB
Richard B.
Aug 18, 2026
Node.js developer
There are almost no words I can express how good Hetvi is. Extremely good at every task I gave her, she was very detailed oriented. When I have more to do or add Hetvi will be the ONLY person I hire to get any type of programming I need done!
YM
Yanky M.
Aug 17, 2026
Fixed $35: Build 1 Medical Database Homepage from Screenshot → Next.js + Tailwind + Vercel`
A pleasure to work with
AM
Amit M.
Jul 8, 2026
Senior React.js Developer for Pair Programming, Debugging, Core Review & Mentorship
Clarity, quality , design, coding, helping, handholding juniors
AM
Amit M.
Mar 9, 2026
Sr React developer required for 1 hour daily mentoring/pair up programming for 10 working days
Hetvi is professional, tech expert and a good team player
DD
Dippuzen D.
Dec 24, 2025
Looking for a Senior Frontend Developer (Next.js + Figma to Code Expert)
Hetvi is one of my favourite freelancer to work with, good communication and egar to dive into any new problems. Would hire her again.
About Hetvi
Full Stack Developer | React.js, Next.js, Node.js
100%
Job Success
Surat, India - 4:25 am local time
With 6+ years of real-world experience, I work on frontend development, UI improvements, SaaS applications, MVPs and full-stack product features by taking full ownership.
What I Can Help You With:
➤ React.js & Next.js development
➤ Build end-to-end SaaS platforms
➤ Develop AI-powered apps & automation systems
➤ Design intuitive, conversion-focused UI/UX
➤ Integrate APIs, payment systems, and third-party tools
➤ Reusable and scalable component architecture
➤ Existing codebase improvements and refactoring
➤ Optimize performance, security, and scalability
Tech Stack:
✅ Frontend: React | React.js | React Redux | Next.js | Vue |TypeScript | JavaScript | Tailwind CSS | SCSS | HTML5 | CSS3 | Bootstrap | Responsive design | Styled Component | Shadcn/ui | MUI | Ant | PWA
✅ Backend: Node.js | Express.js | NestJS | REST API | GraphQL API | Supabase | Prisma
✅ Database: MongoDB | MySQL | PostgreSQL
✅ Cloud: Vercel | Firebase
✅ AI: Claude code | Lovable | ChatGPT | Gemini
✅ Tools: Git | GitHub | Figma | Storybook | Playwright
Why Clients Work With Me:
➤ 6+ years of real-world experience
➤ Clean, scalable, future-proof code
➤ Strong product & business mindset
➤ Clear communication and regular progress updates
➤ Ability to work independently and take ownership
➤ Long-term partnership approach
➤ Reliable delivery with attention to detail
If you need help building a new product, improving an existing application, or implementing frontend features quickly and cleanly, feel free to reach out.
Steps for completing your project
After purchasing the project, send requirements so Hetvi can start the project.
Delivery time starts when Hetvi receives requirements from you.
Hetvi works on your project following the steps below.
Revisions may occur after the delivery date.
Code Review & Issue Reproduction
I clone your repository, set up the environment locally, and reproduce each bug or issue you've reported. I review the affected files, check the architecture, and identify any underlying problems beyond what's been reported.
Root Cause Analysis & Fix Plan
For bugs, I identify the root cause and document why it's happening. I share a clear plan of which files I'll change, what approach I'll take, and any related issues I noticed during the review. You approve the plan before I start writing fixes.