Fix the error "Cannot convert undefined to a BigInt" in Next.js/Web3 application

Budget: 5000 UAH Deadline: 3 days

Hello. I have extensive experience with Next.js. Ready to collaborate. Contact me

Budget: 2000 UAH Deadline: 1 day

Good day!

We are The Dev Company, a team with experience working on Web3 projects, Next.js, Wagmi, Ethers, and Viem.

The error you described (`Cannot convert undefined to a BigInt`) most often occurs because at the moment of calling `BigInt(...)`, one of the parameters is `undefined`. Most likely, this value comes from a form or is incorrectly passed or not initialized before sending. We are ready to quickly localize the source of the problem, check the data transfer logic, parameter typing, and fix the error.

What you will receive:

– Prompt code and parameter transfer logic audit;
– Error fix with verification of all dependent components;
– Testing to confirm that the problem does not recur.

Our stack:

– Next.js, React
– TypeScript
– Wagmi, Viem, Ethers
– Solidity / smart contracts
– GitHub, Vercel, Hardhat / Foundry

We can immediately join the repository and provide a solution in a short time.

We are ready to discuss details; the price for the fix will depend on the scope, but preliminarily within 1000–2000 UAH, depending on complexity.

We look forward to an invitation or additional information.

Best regards,
The Dev Company Expand

Budget: 2000 UAH Deadline: 1 day

I am an experienced Frontend/Fullstack developer with over 15 years of commercial experience. During this time, I have completed dozens of successful projects — from small MVPs to large-scale web systems with thousands of users. I combine deep technical understanding with a pragmatic approach to UX, performance, and maintainability of code.

🔧 My key skills:
- React, Next.js, Node, TypeScript, GraphQL, Redux, Zustand, Python, PHP / Laravel
- CI/CD: experience setting up complete pipelines (GitHub Actions, GitLab CI)
- Automated testing: Jest, React Testing Library, Cypress
- Responsive layout and accessibility (a11y), performance optimization, Lighthouse analysis
- API integration, SPA/PWA development, WebSocket, SSR

📦 Best development practices
I adhere to SOLID, KISS, DRY principles, care about code quality, readability, and maintainability, always write testable code, and work according to CI/CD principles. I can work effectively in a team or independently, meeting deadlines and technical requirements.

Ready to deliver the project with quality, on time, and with attention to detail. Expand

Budget: 2000 UAH Deadline: 1 day

Hello!
I am happy to help. I think it's nothing complicated. Fast and reliable. I can go through the code and check, maybe there are still questions elsewhere.

Budget: 2000 UAH Deadline: 1 day

Good day Bogdan!
Most likely, you are not conveying the meaning accurately, it does not come through; you need to find the place where it disappears. Because undefined means nothing is there.
I will gladly do your task, for your price!
Write to me

Budget: 3500 UAH Deadline: 2 days

Good day!

I have experience working with the Web3 stack: Next.js, TypeScript, Wagmi, Ethers/Viem. I am ready to help identify and fix the TypeError: Cannot convert undefined to a BigInt error that occurs when calling the smart contract. I have recent project experience on this platform with Next.js + TypeScript + web3.

Please send the repository link and clarify: do you use writeContract, prepareWriteContract, or other Wagmi helpers?

Ready to start today.