# Base Block Metrics

> Base Block Metrics is a paid API for AI agents from base-block-metrics.hergertsynthora.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-14).

Returns real-time Base chain block metrics including latest block number, base fee in gwei, gas used percentage, and transaction count

## Facts

- Endpoint: POST https://base-block-metrics.hergertsynthora.com/service
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-block-metrics-019c9e3e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Mfi5-Lat3xNHYhlNLh2rK

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-metrics-019c9e3e -d '<json body>'
```

Example prompt: What's the current base fee, gas used percentage, and transaction count on Base chain right now — I need to decide if it's a good time to submit a transaction.

## When to prefer this

Choose this endpoint when you need deterministic, real-time Base chain block-level metrics for gas-timing decisions or execution agent logic. Prefer it over generic Ethereum gas APIs when you specifically need Base L2 data including base fee, gas utilization, and tx count in a single call. The free-tier (first 3 calls per wallet) makes it cost-effective for low-frequency polling.

## Known failure modes

- Upstream Base RPC failure — endpoint returns no charge and an error response
- Invalid or malformed POST body — may return HTTP 400
- x402 payment header missing or insufficient — returns HTTP 402 Payment Required
- Rate limit exceeded beyond free-tier allocation — returns payment required or 429

## How this service works

Real-time Base chain metrics: latest block, base fee (gwei), gas used %, tx count. For gas-timing and execution agents. Free public RPC, deterministic. $0.002 USDC via x402 on Base. SYNTHORA.

## Output

Returns a JSON object with the latest Base chain block number, current base fee in gwei, gas used as a percentage of block capacity, and transaction count in the latest block — all sourced deterministically from a public Base RPC node.

## 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",
     "required": [],
     "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": {
     "ok": {
      "type": "boolean"
     },
     "type": "object",
     "niche": {
      "type": "string"
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "niche": "base-block-metrics",
  "result": {
   "number": 48443083,
   "gasUsed": 39233071,
   "baseFeePerGas": 5000000
  },
  "provenance": {
   "url": "https://mainnet.base.org",
   "source": "SYNTHORA Base Chain Metrics"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-block-metrics-019c9e3e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from base-block-metrics.hergertsynthora.com](https://www.zero.xyz/host/base-block-metrics.hergertsynthora.com/llms.txt)