# x402 Transaction Verifier (lab.paidapis.net)

> x402 Transaction Verifier (lab.paidapis.net) is a paid API for AI agents from lab.paidapis.net, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-15).

Checks whether a given blockchain transaction hash is confirmed on Base mainnet and returns a signed attestation of its status.

## Facts

- Endpoint: GET https://lab.paidapis.net/api/verify-tx
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-transaction-verifier-lab-paidapis-net-f83fce47
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XvsC5Ee8oBngWujaMgaND

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-transaction-verifier-lab-paidapis-net-f83fce47
```

Example prompt: Can you check whether transaction 0x3a7f2b91c4e0d5a8f6b2c3d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4 is confirmed on Base mainnet and give me a signed attestation of its status?

## When to prefer this

Use this endpoint when you need a lightweight, signed attestation that a specific Base mainnet transaction is confirmed — especially in x402-payment or pay-per-call contexts where you want a cryptographic proof rather than raw RPC data. Prefer it over direct RPC calls when you need the signed signer-address attestation for downstream trust, or when you are building on the x402 protocol stack and want a consistent verification pattern. Not suitable for other chains or for streaming/real-time finality monitoring.

## Known failure modes

- Invalid or malformed txHash (not 32 bytes / wrong format) — likely a 400 or validation error
- Transaction not yet indexed or very recent — may return confirmed: false even if eventually finalizing
- Network or RPC outage on Base — service may be temporarily unavailable
- Payment failure via x402 — call rejected before reaching verification logic if USDC payment is not valid
- Unknown txHash (never existed) — returns confirmed: false with null blockNumber

## How this service works

Oracle: checks whether a base transaction hash has confirmed on-chain, and returns a signed (EIP-191) yes/no attestation — verifiable independently against 0x5a6d60f11C0E33f97E2De12b8B2b70d1B1FE9Efc, without trusting us again on a later call.

## Output

Returns a JSON object with the chain name, the queried txHash, a checkedAt timestamp, a boolean confirmed flag, the block number (or null if unconfirmed), the signer address of the attestation service, and a cryptographic signature over the result — enabling downstream consumers to trust the confirmation report without querying the chain themselves.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "txHash"
 ],
 "properties": {
  "txHash": {
   "type": "string",
   "description": "32-byte transaction hash to check."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "chain": {
   "type": "string"
  },
  "txHash": {
   "type": "string"
  },
  "checkedAt": {
   "type": "string"
  },
  "confirmed": {
   "type": "boolean"
  },
  "signature": {
   "type": "string"
  },
  "blockNumber": {
   "type": [
    "integer",
    "null"
   ]
  },
  "signerAddress": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-transaction-verifier-lab-paidapis-net-f83fce47/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from lab.paidapis.net](https://www.zero.xyz/host/lab.paidapis.net/llms.txt)