# Semilla Base USDC Payment Check

> Semilla Base USDC Payment Check is a paid API for AI agents from agentsmap.io, paid per call via x402, $0.01/call, status unknown (last checked 2026-11-02).

Looks up a Base blockchain transaction by hash and returns its status, block time, and all USDC transfers, with optional verification against an expected recipient address and amount.

## Facts

- Endpoint: GET https://agentsmap.io/semilla/x402/usdc-payment?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/semilla-base-usdc-payment-check-7bfa2a8c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_GEb-mnWhrRKjrCKeE-jm2

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 semilla-base-usdc-payment-check-7bfa2a8c
```

Example prompt: Can you check if Base transaction 0x3a1b2c... actually sent USDC to 0xAbCd... and confirm whether the amount was at least 5.00 USDC?

## When to prefer this

Use this endpoint when you need to verify a specific Base blockchain transaction for USDC payment confirmation, especially in x402 payment flows where you need to validate that a payer sent the correct amount to the correct address before unlocking a resource. Prefer this over generic block explorers when you need structured, machine-readable output that an agent can act on directly.

## Known failure modes

- Invalid or malformed transaction hash (must be 0x + 64 hex chars) returns a validation error
- Transaction not yet indexed or still pending may return incomplete data
- Incorrect expected address format triggers a pattern mismatch error
- Base RPC or indexer unavailability can cause timeouts
- Transaction exists but contains no USDC transfers returns an empty transfer list

## How this service works

Checks one Base transaction on-chain: status, block time and every USDC transfer in it; optionally whether it paid the expected address and amount.

## Output

Returns the on-chain transaction status (success/failed/pending), the block timestamp, a list of every USDC transfer event in the transaction (from, to, amount), and optionally a boolean indicating whether the transaction matches the expected recipient address and amount.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "tx"
     ],
     "properties": {
      "to": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "description": "Expected recipient (optional)"
      },
      "tx": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{64}$",
       "description": "Transaction hash on Base"
      },
      "amount": {
       "type": "string",
       "description": "Expected USDC amount, e.g. 1.5 (optional)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/semilla-base-usdc-payment-check-7bfa2a8c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentsmap.io](https://www.zero.xyz/host/agentsmap.io/llms.txt)