The problem TapOut solves

TapOut

The Problem

Paying someone in crypto shouldn't require a 5-minute conversation:

• "What chain are you on?"
• "Do you have USDC or ETH?"
• "Send me your wallet address"
• Wrong network → stuck funds → frustration

Token and chain fragmentation broke casual payments.

What TapOut Does

Use Cases

In-Person (NFC)

• Split dinner bill
• Pay a friend back
• Community meetups & events

Remote (ENS)

• Send money across cities/countries
• Pay freelancers globally
• Family remittances

What Makes It Better

Tagline

Crypto payments, finally simple.

Challenges we ran into

Challenges I Ran Into

1. ENS Privacy Leak (Critical)

The Problem:
Early in development, our mentors pointed out a major flaw: resolving bob.phoneno.eth returned his main wallet address directly. This meant anyone could view his entire transaction history on Etherscan. We were doxxing users by design.

The Solution:
We built a Privacy Forwarding Contract.

• Users deploy a lightweight forwarder contract.
• ENS records point to the contract address, not the main wallet.
• Funds received auto-sweep to the main wallet internally.
• Result: Public sees only the contract. Main wallet stays hidden.

2. x402 Payment Interception

The Problem:
Integrating HeyElsa's x402 API wasn't just a normal HTTP request. Every call returned HTTP 402 Payment Required. Our initial code crashed because it didn't know how to sign and attach the USDC payment proof automatically.

The Solution:
We wrote a custom axios interceptor using viem:

• Detects 402 responses.
• Parses payment requirements (amount, recipient).
• Signs payment locally with user's wallet.
• Retries request with X-Payment-Token header.
• Result: Seamless micropayments ($0.001 per data call) without user friction.

3. Network Mismatch Errors

The Problem:
During testing, transactions failed with:
Error: network changed: 1 => 11155111
The wallet was on Mainnet, but our agent tried to execute on Sepolia/Base. Ethers.js refused to sign across mismatched networks.

The Solution:
Added a network validation hook before execution:

• Checks current wallet chain ID.
• Prompts user to switch networks if mismatched.
• Forces provider alignment before signing.
• Result: Reliable execution across multiple chains.

4. AI Agent Decision Making

The Problem:
Our first version used hard-coded rules for route selection. It wasn't actually using OpenClaw/AI. We risked missing the HeyElsa bounty criteria.

The Solution:
Refactored the orchestrator to call agent.execute():

• Sends route options to OpenClaw.
• AI analyzes gas, speed, and security.
• Returns structured recommendation with reasoning.
• Result: Genuine AI-powered routing, not just scripted logic.