One of the biggest hurdles we faced was seamlessly integrating multiple technology domains—AI for bin verification, blockchain for rewards, IoT for real-time bin monitoring, and web/mobile interfaces—into a cohesive system. Each component had its own complexities, and making them work together required extensive debugging and middleware development. For instance, syncing the AI model's output with blockchain transactions involved creating custom APIs to bridge Python-based ML services with our Node.js backend and Solidity smart contracts.

Another major pain point was managing gas fees on the Sepolia testnet. While developing the NFT reward system, we encountered unpredictable spikes in transaction costs, which made testing expensive and slow. To mitigate this, we optimized our smart contracts by batching user rewards, implementing off-chain signature verification for minor actions, and only settling critical transactions on-chain. We also built a gas fee estimator to alert users during high-network congestion.

Connectivity issues further complicated our workflow. Intermittent API failures between the frontend, backend, and blockchain nodes caused unexpected crashes, especially during real-time bin tracking. We addressed this by:

Adding retry mechanisms with exponential backoff for failed requests.

Implementing WebSocket fallbacks when REST APIs timed out.

Using local caching to ensure app functionality even with spotty connectivity.

The project demanded relentless effort, including all-night debugging sessions and sleep deprivation. Deployment was particularly tricky—Vercel’s serverless functions timed out during blockchain interactions.

Despite these challenges, we persevered through smart optimizations, better error handling, and sheer determination. The experience taught us invaluable lessons in cross-domain system design, resource management, and teamwork under pressure.