# Carbon Cashmere Multi-Chain Block Height Monitor

> Carbon Cashmere Multi-Chain Block Height Monitor is a paid API for AI agents from api.carbon-cashmere.de, paid per call via x402, $0.005/call, status down (last checked 2026-09-14).

Returns the latest block number and last-update timestamp for seven major blockchains: Arbitrum, Avalanche, Base, Ethereum, Optimism, Polygon, and Solana.

## Facts

- Endpoint: GET https://api.carbon-cashmere.de/v1/chains
- Price: $0.005/call
- Payment: x402
- Status: down
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/api-carbon-cashmere-de-5be94a6a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ZSBGyUReWR6lZgJQTpLLk

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 api-carbon-cashmere-de-5be94a6a
```

Example prompt: Check the latest block heights and update timestamps for all supported chains — Arbitrum, Avalanche, Base, Ethereum, Optimism, Polygon, and Solana — so I can see which ones are live and in sync right now.

## When to prefer this

Choose this endpoint when you need a single call to get current block heights across multiple EVM-compatible chains plus Solana simultaneously — ideal for cross-chain settlement checks, liveness monitoring, or detecting chain sync lag before triggering multi-chain operations. Prefer over chain-specific RPC calls when breadth across seven chains matters more than deep per-chain data.

## Known failure modes

- Upstream node unavailable for one or more chains — partial data returned or stale timestamps
- Rate limit exceeded — HTTP 429 with retry-after header
- Payment not processed — HTTP 402 if x402 payment header is missing or invalid
- All chains unavailable — HTTP 503 or empty response

## How this service works

Professional crypto market intelligence. Real-time prices, signals, and market scoring.

## Output

Returns a JSON object with one entry per supported chain (Arbitrum, Avalanche, Base, Ethereum, Optimism, Polygon, Solana), each containing the latest block number and a timestamp of the last update, suitable for liveness checks and cross-chain sync comparisons.

## Request schema (JSON Schema)

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

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "chains": [
   {
    "chain": "base",
    "last_update": "2026-04-25T10:30:03+00:00",
    "latest_block": 45161828
   },
   {
    "chain": "arbitrum",
    "last_update": "2026-04-25T10:30:03+00:00",
    "latest_block": 456165363
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/api-carbon-cashmere-de-5be94a6a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.carbon-cashmere.de](https://www.zero.xyz/host/api.carbon-cashmere.de/llms.txt)