# Mach Gallery Base ETH Call

> Mach Gallery Base ETH Call is a paid API for AI agents from api.mach.gallery, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-02).

Executes a read-only eth_call on the Base (EVM chain ID 8453) network at a given contract address, returning the raw hex result.

## Facts

- Endpoint: POST https://api.mach.gallery/api/base/eth-call?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/mach-gallery-base-eth-call-779f53f7
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_USD2nJXZSkieDvO_Veq6R

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 mach-gallery-base-eth-call-779f53f7 -d '<json body>'
```

Example prompt: Call the Base smart contract at 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 with calldata 0x70a08231000000000000000000000000abcdef1234567890abcdef1234567890abcdef12 at the latest block and give me the raw result.

## When to prefer this

Choose this endpoint when you need pay-per-call, keyless access to Base (EVM chain 8453) contract read operations without managing API key subscriptions or running your own node. It is ideal for autonomous agents that make infrequent or unpredictable call volumes and want to pay exactly $0.005 USDC per query via x402. Prefer it over self-hosted RPC nodes or subscription-based providers when cost predictability and zero-setup are priorities for Base-specific smart contract queries.

## Known failure modes

- Invalid EVM address format (must be 0x + 40 hex chars) returns a 400 validation error
- Malformed or oversized calldata (>32770 hex chars) rejected with 400
- Contract reverts: result may contain revert reason encoded in hex
- Non-existent contract address returns 0x (empty result, no code at address)
- Payment failure via x402 (insufficient USDC balance) results in 402 response before execution
- Unknown or invalid block number/tag returns an error from the underlying node

## How this service works

Fast, low-cost Base data for autonomous agents. No API keys, no subscriptions; pay per call with USDC over x402.

## Output

A JSON object containing 'result' (the raw ABI-encoded hex return value from the contract call) and 'network' (always 'eip155:8453' for Base). If the call reverts or the address has no code, appropriate error data is returned.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "to": {
   "type": "string",
   "pattern": "^0x[0-9a-fA-F]{40}$",
   "description": "Smart-contract address on Base mainnet."
  },
  "data": {
   "type": "string",
   "pattern": "^0x[0-9a-fA-F]*$",
   "maxLength": 32770,
   "description": "0x-prefixed ABI calldata for a read-only eth_call."
  },
  "block": {
   "anyOf": [
    {
     "type": "string"
    },
    {
     "type": "integer",
     "minimum": 0
    }
   ],
   "description": "Base block selector: block number or tag such as latest, safe, finalized, pending or earliest."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "result": "0x",
  "network": "eip155:8453"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/mach-gallery-base-eth-call-779f53f7/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.mach.gallery](https://www.zero.xyz/host/api.mach.gallery/llms.txt)