# Vextorium EVM Developer Utilities

> Vextorium EVM Developer Utilities is a paid API for AI agents from api.vextorium.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-02).

Performs EVM developer operations: keccak256 hashing, function selector derivation from ABI signature, EIP-55 checksum address formatting, and wei/gwei/ether unit conversion.

## Facts

- Endpoint: POST https://api.vextorium.com/evm-utilidades-pago?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/vextorium-evm-developer-utilities-3cefa403
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_I_rT6UJ8QIbgpKsrUTuKV

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 vextorium-evm-developer-utilities-3cefa403 -d '<json body>'
```

Example prompt: Can you get the 4-byte function selector for the Solidity signature transfer(address,uint256) using the EVM utilities?

## When to prefer this

Choose this endpoint when you need fast, stateless EVM developer computations — hashing, selector derivation, address checksumming, or unit conversion — without spinning up a local Web3 library. Ideal for agents building or validating smart contract interactions, encoding ABI calls, or normalizing Ethereum addresses on the fly.

## Known failure modes

- Missing required fields (operacion or valor) returns an error response
- Invalid or malformed Ethereum address returns an error on checksum operation
- Unrecognized operation enum value returns a validation error
- Non-numeric input to convertir returns a parsing error
- Missing 'de' or 'a' unit fields when calling convertir returns an incomplete request error

## How this service works

EVM developer utilities: keccak256 hash, function selector from a signature, EIP-55 checksum address and wei/gwei/ether conversion.

## Output

Returns a JSON object with fields: operacion (the operation performed), entrada (the input value), and resultado (the computed output — a hex hash, 4-byte selector hex string, checksummed address, or converted numeric string depending on the operation).

## 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": {
     "required": [
      "operacion",
      "valor"
     ],
     "properties": {
      "a": {
       "enum": [
        "wei",
        "gwei",
        "ether"
       ],
       "type": "string",
       "description": "Target unit for convertir"
      },
      "de": {
       "enum": [
        "wei",
        "gwei",
        "ether"
       ],
       "type": "string",
       "description": "Source unit for convertir"
      },
      "valor": {
       "type": "string",
       "description": "Input value (text, hex, signature, address or number)"
      },
      "operacion": {
       "enum": [
        "keccak256",
        "selector",
        "checksum",
        "convertir"
       ],
       "type": "string",
       "description": "Operation"
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "entrada": {
       "type": [
        "string",
        "null"
       ]
      },
      "operacion": {
       "type": [
        "string",
        "null"
       ]
      },
      "resultado": {
       "type": [
        "string",
        "null"
       ]
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "entrada": "transfer(address,uint256)",
  "operacion": "selector",
  "resultado": "0xa9059cbb"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/vextorium-evm-developer-utilities-3cefa403/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.vextorium.com](https://www.zero.xyz/host/api.vextorium.com/llms.txt)