# x402 Base USDC/ETH Lookup

> x402 Base USDC/ETH Lookup is a paid API for AI agents from x402-lookup-seller.fly.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-14).

Verifies a Base chain USDC payment transaction or checks the ETH and USDC balances of a wallet address before retrying a payment.

## Facts

- Endpoint: GET https://x402-lookup-seller.fly.dev/v1/base/status
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-base-usdc-eth-lookup-37cfedf0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_49uqZy4VBR26Iy3_svi6p

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability x402-base-usdc-eth-lookup-37cfedf0
```

Example prompt: Can you verify whether the Base USDC payment with transaction hash 0xabc123...def456 went through, or check the USDC and ETH balance of wallet 0x1234...abcd before I retry?

## When to prefer this

Use this endpoint when you need to verify a Base chain USDC payment by transaction hash or check wallet balances (ETH + USDC on Base) before deciding whether to retry an x402 payment. Prefer this over generic block explorers when the agent needs a structured, machine-readable response rather than a human-readable page, and when the use case is specifically Base chain USDC payment verification.

## Known failure modes

- Invalid tx hash format (not 0x + 64 hex) returns an error
- Invalid address format (not 0x + 40 hex) returns an error
- Providing both tx and address simultaneously is rejected (mutually exclusive)
- Providing neither tx nor address returns a validation error
- Transaction not yet indexed may return not-found temporarily
- Network or node unavailability may cause timeouts

## How this service works

Base transaction status and USDC balance checks for settlement verification. Pass exactly one of hash= (or tx=) for a Base tx receipt with usdcIn/usdcOut, or address= for ETH+USDC balances and recent USDC transfers. Use when verifying a Base USDC payment or checking a wallet before retry.

## Output

Returns the status of a Base chain transaction (confirmed, pending, failed, not found) when queried by tx hash, or the current ETH and USDC balances of a wallet address when queried by address — enabling agents to verify payments or assess funds before retrying.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-base-usdc-eth-lookup-37cfedf0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-lookup-seller.fly.dev](https://www.zero.xyz/host/x402-lookup-seller.fly.dev/llms.txt)