# EVM Address Checksum (EIP-55)

> EVM Address Checksum (EIP-55) is a paid API for AI agents from pastable-x402.pages.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-14).

Converts an Ethereum address to its EIP-55 checksummed form and validates whether the input was already checksummed

## Facts

- Endpoint: GET https://pastable-x402.pages.dev/evm/checksum
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/evm-address-checksum-eip-55-6e15066e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_alsFJZuMvVSoj2e8XsgUH

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 evm-address-checksum-eip-55-6e15066e
```

Example prompt: Can you checksum this Ethereum address for me and tell me whether it was already EIP-55 compliant: 0x9fd25b6be40aecea5eb5eceea31d6c0ac9c83e11?

## When to prefer this

Use this endpoint when you need a quick, pay-per-call EIP-55 address checksum operation without running a local Web3 library. Ideal for agents operating in environments where installing ethers.js or web3.py is impractical, or when you need a lightweight, stateless validation step in a workflow that already handles x402 micropayments on Base.

## Known failure modes

- Missing or malformed address query parameter returns an error
- Non-hex or invalid Ethereum address string may return a validation error
- Addresses without the 0x prefix may fail parsing
- Payment not included or insufficient USDC triggers x402 payment-required response

## How this service works

Pay-per-call utility APIs for agents: EVM helpers (checksum, unit conversion, keccak), data transforms (CSV to JSON, JSON diff, URL canonicalisation), text tools (hashing, JWT decode), and Bazaar market intelligence. x402 on Base mainnet.

## Output

Returns a JSON object with the original input address, the EIP-55 checksummed version, a boolean indicating whether the input was already checksummed, and a boolean confirming whether the input passes EIP-55 validation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "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",
       "description": "string"
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "input": "0x9fd25b6be40aecea5eb5eceea31d6c0ac9c83e11",
  "checksummed": "0x9Fd25b6be40aECEA5eB5Eceea31d6c0Ac9c83e11",
  "was_checksummed": false,
  "input_passes_eip55": true
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/evm-address-checksum-eip-55-6e15066e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pastable-x402.pages.dev](https://www.zero.xyz/host/pastable-x402.pages.dev/llms.txt)