I will diagnose and fix your react or nextjs production bug

Is your React or Next.js application failing in production, showing an intermittent error, or behaving differently after deployment?

I am a Japan-based senior full stack engineer with 13+ years of experience across SaaS, e-commerce, recruiting systems, APIs, SQL databases, AWS, Docker, and Cloudflare. I help teams turn unclear production problems into a reproducible issue, a focused fix, and clear verification notes.

Depending on the package, I can:

- reproduce and investigate one production issue

- trace frontend, API, authentication, database, or deployment behavior

- identify the likely root cause and risks

- implement the smallest agreed safe fix

- add or update relevant tests

- verify the result in the available environment

- provide fix and deployment notes

The Diagnostic package is investigation and a fix plan only. The Focused Fix covers one agreed issue. The Stabilization Sprint covers a small group of related issues and stronger verification.

Before ordering, please share the current behavior, expected result, stack, logs or screenshots, repository access method, and deadline. If the scope is unclear, message me first so we can select the right package.