Switch to English?
Yes
Переключитись на українську?
Так
Переключиться на русскую?
Да
Przełączyć się na polską?
Tak
Post your project for free and start receiving proposals from freelancers within minutes after publication!

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

Translated45 USD

  1. 823
     3  0

    1 day45 USD

    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.

  2. 1887    8  0
    1 day45 USD

    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

  3. 181  
    1 day45 USD

    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.

  4. 94294    1269  1   10
    3 days111 USD

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

  5. 532    5  1
    1 day45 USD

    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

  6. 1563    4  0   1
    2 days78 USD

    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.

  7. Another 3 proposals concealed
    1 proposal concealed
  • Pavlo B.
    30 July 2025, 8:42 |

    Спробуйте поревірку
    if (variable === undefined) { // catch error; }

Current freelance projects in the category Cryptocurrency & Blockchain

Need Smart Contract Engineer/Mentor

8000 USD

I want to find the Smart Contract Engineer/Mentor who has rich experience in Solidity smart contract development.

Cryptocurrency & BlockchainEngineering ∙ 5 days 10 hours back ∙ 11 proposals

Client
Bohdan Hrinchenko
Ukraine Aleksandriya
Project published
10 months 18 days back
117 views
Tags
  • web3
  • ethers
  • Next.js
  • TypeScript
  • wagmi