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I will fix react and nextjs bugs in your saas web app
Javkhlant.A
About this gig
If your React or Next.js SaaS app is throwing errors, breaking after an update, or behaving differently in production, I can help.
I have 5 years of experience building production software, including systems for one of Mongolias largest banks. Ive also shipped live SaaS, booking, e-commerce, and streaming products.
Portfolio: https://javkhlant.dev/
I dont just patch the visible symptom. I reproduce the issue, find the root cause, implement the smallest clean fix, and test the affected flow.
I can help with:
React and Next.js bugs
Runtime, build, hydration, and deployment errors
UI, state, routing, and form issues
API and frontend/backend integration bugs
Authentication and session problems
Stripe, Supabase, and third-party API issues
What happens after you order:
1. You send the issue, expected behavior, reproduction steps, and required access.
2. I diagnose the root cause and confirm the scope.
3. I implement and test the fix.
4. You receive the updated code plus a clear explanation of what changed.
One bug means one specific issue, or multiple errors caused by the same root problem.
If you're unsure which package fits, message me first.
Respect third-party rights
Please be aware that it is against Fiverr's policies for sellers to include themes, templates, or any other elements that infringe third-party rights or applicable laws in the delivered work. Read more about in our Guide to Responsible Digital Creation.
Get to know Javkhlant.A
Javkhlant.A
NextJS SaaS Developer for MVPs and Integrations
- FromMongolia
- Member sinceAug 2026
- Avg. response time1 hour
Languages
Mongolian, English
I have 5 years of experience building production software, including work for one of Mongolia’s largest banks. I’ve also shipped live SaaS, e-commerce, booking, and streaming products used by real customers. I help startups and founders build, launch, and improve SaaS products with Next.js and TypeScript. I can build MVPs, add features, fix bugs, and integrate Stripe, Supabase, authentication, databases, and third-party APIs. I focus on clean, maintainable code, clear communication, and practical solutions that are ready for real users.
My Portfolio
FAQ
What counts as one bug?
One bug means one specific issue or multiple errors caused by the same underlying problem. For example, several UI errors caused by one authentication failure would usually count as one bug. Unrelated issues are considered separate bugs.
Do I need to contact you before ordering?
Not for a small, clearly defined issue. If the problem is complex, intermittent, production-only, or you’re unsure which package fits, send me a message first and I’ll help you choose the right scope.
What do you need from me to start?
Please provide a clear description of the issue, what you expected to happen, what currently happens, steps to reproduce it, and any screenshots or error messages you have. I’ll also need access to the relevant source code and, when necessary, test credentials or environment details.
Can you work with an existing or unfamiliar codebase?
Yes. This gig is specifically designed for existing React and Next.js projects. I can step into an unfamiliar codebase, understand the relevant area, and debug it without needing the entire application rewritten.
Can you fix Stripe, Supabase, authentication, or API issues?
Yes, when the existing implementation is broken or behaving incorrectly. If you need a completely new Stripe, Supabase, authentication, or API integration built from scratch, that would be better handled as a separate development project.
Can you fix production-only issues?
Yes, provided I have enough information or access to reproduce and investigate the problem. This may include deployment logs, environment configuration, hosting access, or production error details.
Do you deploy the fix as well?
Deployment assistance is available as a Gig Extra. Otherwise, I’ll deliver the completed code and explain what needs to be deployed.
What does a revision include?
A revision covers adjustments related to the original agreed issue and the fix I delivered. It does not include new features, unrelated bugs, redesigns, or additional functionality.
What if the bug is larger than expected?
If I discover that the issue is significantly larger or different from the package scope, I’ll explain what I found before doing additional work.
Can you guarantee that every bug can be fixed?
Most software issues can be diagnosed and resolved, but some problems depend on unavailable third-party services, missing source code, infrastructure restrictions, or access I don’t control. If an external limitation prevents a complete fix, I’ll clearly explain what I found and the recommended next
