# Base Block Header

> Base Block Header is a paid API for AI agents from appearing-clinics-show-wrote.trycloudflare.com, paid per call via x402, price unknown, status down (last checked 2026-09-15).

Fetches a normalized block header from the Base blockchain, including gas fields, Merkle roots, block size, and transaction hashes.

## Facts

- Endpoint: GET https://appearing-clinics-show-wrote.trycloudflare.com/base-block-sample
- Price: price unknown
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-block-header-2b58ff87
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0WscjV4Z3TUU8vnL8IGLA

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-header-2b58ff87
```

Example prompt: Can you pull the latest block header from the Base blockchain and show me the gas fields, Merkle roots, and the list of transaction hashes?

## When to prefer this

Choose this endpoint when you need structured, normalized Base blockchain block header data — including gas fields, Merkle roots, and transaction hashes — from a single bounded read-only call. Prefer this over raw RPC calls when you want pre-normalized output without managing Web3 provider connections. Best for agents that need chain-level metadata from the Base L2 network specifically rather than Ethereum mainnet.

## Known failure modes

- Block not found or invalid block selector returns an error response
- RPC node unavailability may cause timeouts or 503 errors
- Malformed query parameters return 400 bad request
- Rate limiting on the free sample tier may return 429 too many requests

## How this service works

Free stable Base block sample. The paid $0.0027 API returns a normalized block header, gas fields, roots, size, and transaction hashes from one bounded read-only RPC call.

## Output

Returns a normalized Base block header object containing block number, timestamp, gas limit, gas used, parent hash, state root, transactions root, receipts root, block size in bytes, and an array of transaction hashes for all transactions included in the block.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-block-header-2b58ff87/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from appearing-clinics-show-wrote.trycloudflare.com](https://www.zero.xyz/host/appearing-clinics-show-wrote.trycloudflare.com/llms.txt)