# Nimbus Onchain Data API – /check Endpoint Health Probe

> Nimbus Onchain Data API – /check Endpoint Health Probe is a paid API for AI agents from crypto-data-api-zo95.onrender.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-17).

Checks whether a given x402 pay-per-call API URL is reachable, properly configured, and returning valid x402 payment envelopes

## Facts

- Endpoint: POST https://crypto-data-api-zo95.onrender.com/check?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-17
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/nimbus-onchain-data-api-check-endpoint-health-probe-65c0b01e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_kRyD-q0e98nUDJzfiJ79v

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 nimbus-onchain-data-api-check-endpoint-health-probe-65c0b01e -d '<json body>'
```

Example prompt: Can you check whether this x402 API endpoint is reachable, returning proper 402 responses, and what its 24-hour fail rate looks like? The URL is https://crypto-data-api-zo95.onrender.com/api/wallets.

## When to prefer this

Use this endpoint when you need to programmatically verify that a specific x402 pay-per-call API URL is properly configured, reachable, and behaving correctly — especially before integrating it into an agent workflow, auditing it for leaking free responses, or monitoring its reliability over time. Prefer this over general HTTP ping tools when you need x402-specific envelope and schema validation details.

## Known failure modes

- URL not provided or malformed — likely returns a 400 or validation error
- Target endpoint is unreachable — reachable field returns false
- Target endpoint not configured as x402 — envelope_parses or schema fields may be null/false
- Service itself may be unavailable (hosted on Render free tier, which can sleep) — connection timeout
- Data may be delayed or stale — last_probe_block timestamp may be old

## How this service works

x402 pay-per-call. Payments are per request in USDC and are final. No refunds on-chain. Service is provided as-is and may change or stop without notice. Informational data only, not financial, investment, legal, or tax advice. Metrics such as net transfer volume estimates and wallet clusters are algorithmic estimates from public blockchain data and may be wrong or delayed. Provided as-is with no warranty. Methodology: https://crypto-data-api-zo95.onrender.com/methodology.

## Output

Returns a JSON object containing: whether the URL is reachable, the HTTP status code observed, the x402 payment asset (e.g. USDC), price in human-readable and atomic form, the network (e.g. Base), whether a 200 was leaked without payment, the 24-hour fail rate and probe count, whether the payment envelope parses correctly, advertised and returned schemas, and the timestamp and block number of the last probe.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "url": "https://example.com/api",
  "asset": "USDC",
  "price": {
   "human": "0.02",
   "atomic": "20000",
   "decimals": 6
  },
  "network": "base",
  "reachable": true,
  "checked_at": "2026-09-29T19:40:00Z",
  "leaked_200": false,
  "http_status": 402,
  "fail_rate_24h": {
   "rate": "0.00",
   "probes": 1
  },
  "schema_missing": null,
  "envelope_parses": true,
  "last_probe_block": {
   "at": "2026-09-29T19:40:00Z",
   "block": "12345"
  },
  "schema_advertised": [
   "status"
  ],
  "schema_returned_last_settled": null
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/nimbus-onchain-data-api-check-endpoint-health-probe-65c0b01e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from crypto-data-api-zo95.onrender.com](https://www.zero.xyz/host/crypto-data-api-zo95.onrender.com/llms.txt)