👾 I Built a Chatbot on Blockchain: It Was Cool Until It Cost Me $43 in Gas Fees

Ever wanted to combine a chatbot with blockchain? Neither did I—until curiosity, caffeine, and an overinflated sense of confidence took over.

Here’s how it started, where it broke, and why you might want to try it anyway (but probably on a testnet).

💡 The "Brilliant" Idea

I thought: what if I could make a chatbot that runs on-chain? You ask it something, it responds. All interactions logged, verified, and visible to the world.

Totally transparent. Totally trustless. Totally expensive, apparently.

🔨 Stack & Setup

  • Smart contract on Ethereum (Solidity)
  • Front-end on React + Ethers.js
  • AI model accessed via API (off-chain for now)
  • User sends message → stored on-chain → triggers AI → logs response

Simple in theory. A little janky in practice. Like IKEA furniture but with gas fees.

🧪 First Test: "Hello, world!"

I deployed the contract.

Typed "Hello, world!" in the chatbot.

Transaction sent.

Boom—$5 in gas just to say hello.

The blockchain now officially knows I exist, and my wallet officially hates me.

🔁 The Scaling Problem

For every new message:

  • The user sends a transaction
  • AI responds off-chain
  • Smart contract records it

It was working. But after 10 messages, I realized I had burned more ETH than I’d like to admit publicly.

Spoiler: It hit $43 in one afternoon.

Just to chat with myself. 🙃

😅 What I Learned

  • Blockchains are not made for real-time chat. Unless you're into paying $0.50 per "lol".
  • AI + Blockchain needs hybrid architecture. Keep the logic off-chain, store hashes on-chain if necessary.
  • Testnet is your best friend. Rinkeby, Sepolia, whatever—just not Mainnet. Save your sanity and ETH.

✅ Would I Do It Again?

Honestly… yeah. But smarter.

I'd:

  • Use a Layer 2 (Arbitrum, Polygon, Base)
  • Store chat logs off-chain (IPFS or db)
  • Sign messages, not send tx every time

Lesson learned: just because you can put something on-chain doesn’t mean you *should*.

🔗 Wanna Try It Yourself?

Here’s the repo if you’re feeling brave (or just bored):

👉 Blockchain ChatBot

Fork it, improve it, meme it.

🧠 Final Thought

The idea of a decentralized chatbot is cool. But Ethereum gas fees are colder than my ex’s last text.

Until blockchain UX improves, let’s just say:

On-chain AI is the future — just not for chatting… yet.

Curious? Confused? Want to roast my gas fee decisions? Drop it in the comments.

🔗 P.S. I write more AI & Blockchain chaos on my blog:

👉 AI & Blockchain Hub — come hang out, laugh, learn, and watch me break stuff so you don’t have to.