# Agent402 Ethereum Address EIP-55 Checksum Validator

> Agent402 Ethereum Address EIP-55 Checksum Validator is a paid API for AI agents from agent402.co.uk, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).

Validates and normalizes an Ethereum address to its EIP-55 checksummed form, returning validity status and canonical casing.

## Facts

- Endpoint: POST https://agent402.co.uk/v1/validate/eth-address
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent402-ethereum-address-eip-55-checksum-validator-dfc2dfb9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_MtBV1SSjqElRW5FW4s__j

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 agent402-ethereum-address-eip-55-checksum-validator-dfc2dfb9 -d '<json body>'
```

Example prompt: Can you validate and checksum this Ethereum address for me — 0x9ef92b278a3867c429751390ec427736eb4babb2 — and tell me if it's properly formatted?

## When to prefer this

Use this endpoint when your agent needs a pure structural and checksum validation of an Ethereum address — with no on-chain lookup, no balance check, and no ENS resolution. It is ideal for input sanitization pipelines, pre-transaction guards, and anywhere you need the canonical EIP-55 mixed-case form of an address cheaply and deterministically at $0.001 per call. Prefer it over on-chain RPC calls when you only need format correctness, not account state.

## Known failure modes

- Malformed address (not 40 hex chars after 0x) returns valid: false
- Non-hex characters in address body cause validation failure
- Missing 0x prefix may cause invalid result
- Address with correct length but invalid hex digits returns valid: false
- Network/payment errors return HTTP 402 or 5xx status

## How this service works

Don't burn tokens on deterministic work. Go/no-go jobs first: payout preflight, text firewall (PII/secrets), budget check — then rails, calendars, finmath. x402 USDC on Base. UK + global. agent402.co.uk — not agent402.tools. $0.001–$0.002 USDC on Base. No API keys.

## Output

Returns a JSON object with a boolean 'valid' field indicating whether the input is a structurally valid Ethereum address, and a 'checksummed' string field containing the EIP-55 mixed-case canonical form of the address (e.g. {"valid": true, "checksummed": "0x9EF92b278a3867C429751390EC427736eB4BABB2"}). Does not check on-chain balance, ENS names, or contract existence.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "address": {
   "type": "string",
   "description": "0x address"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "valid": true,
  "checksummed": "0x9EF92b278a3867C429751390EC427736eB4BABB2"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent402-ethereum-address-eip-55-checksum-validator-dfc2dfb9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agent402.co.uk](https://www.zero.xyz/host/agent402.co.uk/llms.txt)