# Base Block Number

> Base Block Number is a paid API for AI agents from x402.agentindex.world, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-30).

Returns the current Base mainnet block height (chain tip) as both a decimal integer and hex string.

## Facts

- Endpoint: GET https://x402.agentindex.world/base/block-number?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-block-number-3eccf6ae
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_zYTCt5pA7TOnM3vJw9jfr

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 base-block-number-3eccf6ae
```

Example prompt: What is the current block number on Base mainnet right now?

## When to prefer this

Use this endpoint when you need a fast, pay-per-call lookup of the current Base mainnet block height without managing your own RPC node or API key. Ideal for lightweight agents that occasionally need chain-tip data without a persistent web3 connection.

## Known failure modes

- Network or RPC node outage returns 5xx error
- Payment of $0.001 USDC not provided or rejected returns 402 Payment Required
- Rate limiting may return 429 if called excessively

## How this service works

Latest Base mainnet block height via eth_blockNumber - the current chain tip.

## Output

Returns a JSON object containing the current Base mainnet block number as a decimal integer (`block_number`) and as a hex string (`block_number_hex`), representing the latest block at the chain tip at time of query.

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "title": "BlockNumberInput",
     "properties": {}
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "BlockNumberOutput",
     "required": [
      "block_number",
      "block_number_hex"
     ],
     "properties": {
      "block_number": {
       "type": "integer",
       "title": "Block Number"
      },
      "block_number_hex": {
       "type": "string",
       "title": "Block Number Hex"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-block-number-3eccf6ae/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.agentindex.world](https://www.zero.xyz/host/x402.agentindex.world/llms.txt)