# X402 Hub Chain Check

> X402 Hub Chain Check is a paid API for AI agents from x402-hub.vercel.app, paid per call via x402, $0.144192/call, status unknown (last checked 2026-09-14).

Checks blockchain/chain-related data or status via a query string, protected by x402 micropayments on Base

## Facts

- Endpoint: POST https://x402-hub.vercel.app/api/chaincheck
- Price: $0.144192/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-hub-chain-check-848889a4
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_K5okxw5RjQ5ismNBFOl_N

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-hub-chain-check-848889a4 -d '<json body>'
```

Example prompt: Can you run a chain check on 'ETH mainnet block 19000000' and tell me what comes back?

## When to prefer this

Use this endpoint when you need to check or verify blockchain/chain-level data using a text query, and you are operating in a Web3/x402 micropayment environment on Base. Prefer this over general blockchain explorers when you want a programmatic, agent-callable API that accepts micropayments via x402.

## Known failure modes

- Missing or empty 'query' field returns a validation error
- Invalid or unrecognized query format may return empty or null data
- Payment failure or insufficient USDC balance returns HTTP 402
- Upstream blockchain API unavailability causes service errors
- Malformed JSON body results in a 400 error

## How this service works

63 paid API endpoints protected by x402 micropayments on Base

## Output

Returns a data object containing the response from the upstream chain-check API, typically on-chain or blockchain-related information corresponding to the submitted query string.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "query"
 ],
 "properties": {
  "query": {
   "type": "string",
   "description": "Query parameter for the API"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "data": {
   "type": "object",
   "description": "Response data from upstream API"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-hub-chain-check-848889a4/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-hub.vercel.app](https://www.zero.xyz/host/x402-hub.vercel.app/llms.txt)