Building EchoFi was honestly way harder than I expected when I started. The concept seemed straightforward - combine XMTP messaging, AI agents, and smart contracts - but getting these three technologies to actually work together turned into a debugging marathon.

The XMTP v3 database corruption issue became my biggest enemy. I'd get everything working perfectly, then randomly the app would just break with these cryptic "SequenceId" errors. Turns out XMTP v3 uses SQLite for local storage, and something about the way messages sync between devices kept corrupting the database. I spent probably two full days just building error handling around this - retry logic, automatic database resets, fallback loading states. The worst part was it would work fine on my laptop, then I'd test on my phone and boom, everything's broken again.

I ended up having to build this nuclear option where the app can completely wipe and recreate the local database. Not exactly the smooth user experience I was going for, but at least people could get unstuck when things went sideways. The amount of error handling code I wrote around XMTP is honestly embarrassing - there's probably more error handling than actual functionality.

AgentKit integration was another nightmare. The documentation makes it look simple, but trying to use it in a Next.js app was like fitting a square peg in a round hole. AgentKit is designed for Node.js servers, but I needed to call it from React components. I kept getting these weird build errors about server-side modules being imported on the client side.

I finally figured out I had to keep all the AgentKit stuff on the server and communicate through API routes, but then I had this whole other problem of managing state between the frontend and backend. Half the features in my agent hook are just placeholder functions returning "not implemented yet" because I couldn't get the real integrations working reliably.

The CORS headers thing was subtle but deadly. XMTP v3 requires these specific Cross-Origin headers to work in browsers, and if you get them wrong, nothing fails loudly - it just silently doesn't work. I probably spent six hours debugging why XMTP was initializing but not loading conversations, only to discover it was a missing CORS header. The error messages were completely unhelpful too.
Getting all the environment variables right was like juggling knives. You need CDP API keys for AgentKit, OpenAI keys for the LLM, database URLs for Supabase, network configurations for Base, XMTP environment settings - and if any one of them is wrong, something breaks in a weird way. I built this whole environment validation system just to catch configuration errors early, because debugging a broken API key at runtime sucked.

The cross-device message sync problem with XMTP v3 was particularly frustrating because it worked inconsistently. Sometimes messages would sync fine between my laptop and phone, sometimes they'd be completely out of order, sometimes they wouldn't appear at all. The v3 architecture with Installation IDs and Inbox IDs is supposed to be more secure, but it made debugging way harder because each device has its own identity.

How I dealt with all this: Basically, I gave up on having everything work perfectly and focused on making sure I could demo the concept. I built mock versions of features that weren't working, added tons of error boundaries so the app wouldn't completely crash when something broke, and prepared backup screenshots for the demo in case the live version decided to have issues.

The smart contract stuff actually worked pretty well - Foundry and Base were solid. But the messaging and AI integration pieces were like building on quicksand. Every time I fixed one issue, two more would pop up.

By the end, I had this weird hybrid where some features were fully functional, others were mocked for demo purposes, and everything was wrapped in enough error handling to survive a nuclear winter. It's not pretty under the hood, but it demonstrates the concept well enough for a buildathon.

The most frustrating part was that each individual technology - XMTP, AgentKit, Base - works fine on its own. But combining them revealed all these edge cases and integration issues that you'd never hit building a simple example app. That's probably the biggest lesson: ambitious integrations need way more development time than you think, especially when you're working with bleeding-edge protocols.

Creedible links about this project is found on the attached githubs readmeFIle