# Base Chain ETH Balance

> Base Chain ETH Balance is a paid API for AI agents from market.561.group, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-12).

Returns the live native ETH balance (in wei) for a given Base network address, along with the snapshot block number at which it was read.

## Facts

- Endpoint: GET https://market.561.group/v1/base-chain/balance?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-12
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/base-chain-eth-balance-c594055d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ZywUtrcfsd79BZDPor5ni

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-chain-eth-balance-c594055d
```

Example prompt: What's the current ETH balance on Base for wallet address 0x742d35Cc6634C0532925a3b8D4C9B7C1f3a9E2b4?

## When to prefer this

Use this endpoint when you need a real-time, live-read native ETH balance on the Base network for a specific address and also need the snapshot block for auditability or consistency checks. Prefer this over general Ethereum balance APIs when the target chain is specifically Base (L2). Ideal for agents that need to gate actions on sufficient ETH balance or monitor wallet health on Base.

## Known failure modes

- Invalid or malformed Ethereum address (not matching ^0x[0-9a-fA-F]{40}$) returns a validation error
- RPC node unavailability may cause timeouts or 503 errors
- Address with zero balance returns weiBalance of '0' (not an error)
- Missing required 'address' query parameter returns a 400-level error
- Payment not received (x402 protocol) results in 402 Payment Required

## How this service works

Native ETH balance for one Base network address, read live from a public Base RPC node (eth_getBalance) and returned with the snapshot block it was read at.

## Output

Returns a JSON object containing the queried address, the native ETH balance expressed as a wei string, and the block number (snapshotBlock) at which the balance was read from the Base RPC node.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "address"
     ],
     "properties": {
      "address": {
       "type": "string",
       "pattern": "^0x[0-9a-fA-F]{40}$",
       "description": "The Base network address to read."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "required": [
      "address",
      "weiBalance",
      "snapshotBlock"
     ],
     "properties": {
      "address": {
       "type": "string"
      },
      "weiBalance": {
       "type": "string"
      },
      "snapshotBlock": {
       "type": "string"
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/base-chain-eth-balance-c594055d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from market.561.group](https://www.zero.xyz/host/market.561.group/llms.txt)