The challenge & approach
The client brought an existing crowdfunding application with issues across the frontend, backend, database, wallet and smart contracts. I reviewed it, agreed a remediation plan with the client, completed the work, tested it and delivered the finished project.
Approach
I began with a technical assessment of the existing Next.js, MongoDB and Ethereum application. I documented the issues and broke the work into milestones for the client. After the client approved the plan, I carried out the agreed development and remediation work, tested the updated platform and successfully delivered it.
Technical architecture
The diagram illustrates the reviewed application's conceptual layers, not a verified production deployment.
Campaigns, content and wallet UI
Application operations
Wallet connection
Off-chain data
On-chain transactions
The development work covered the interaction between frontend components, backend APIs, MongoDB data and blockchain wallet/contract flows. The diagram shows the application's conceptual architecture without exposing confidential code.
Platform features & integration
- Next.js/React frontend and API routes
- MongoDB/Mongoose models
- Ethereum campaign smart contracts
- MetaMask and Sepolia integrations
- Supporting articles, comments, subscriptions and email features
Problems identified and addressed
- RPC reliability: Sepolia requests and cross-origin failures
- Numeric safety: avoid converting large wei values to unsafe JavaScript numbers
- React hook dependency warnings
- Dependency vulnerabilities requiring controlled review
- Smart contract campaign IDs, funding limits, refunds and ownership
- Wallet-based authorization must verify actual wallet ownership
- Unbounded refund loops and transfer-failure concerns
Project delivery milestones
Environment setup and technical audit
Set up the application, reviewed architecture and dependencies, identified technical risks, and presented issues and proposed milestones to the client.
Frontend and API improvements
Implemented the agreed frontend and API improvements, addressing application reliability, validation, component behavior and error handling.
Wallet and campaign hardening
Worked on the agreed wallet, blockchain and campaign-flow fixes, including transaction handling and integration reliability.
QA, security and deployment preparation
Tested the corrected application, performed final checks and delivered the completed project to the client.
Quality & validation
- Performed: local setup, production build, route checks and code inspection
- Performed: frontend and API testing after the agreed fixes
- Tested blockchain-dependent campaign and wallet behavior after the agreed changes
- Completed final functional testing before handover; detailed test logs are not publicly shared
Successful client delivery
After reviewing the existing codebase, I presented the issues and a milestone-based implementation plan to the client. With approval, I implemented the agreed fixes, tested the application and successfully delivered the completed Web3 crowdfunding platform.
The work focused on more reliable application flows, safer blockchain interactions and maintainable code. No numerical performance or customer-impact metrics are claimed.