# EVM Address Checksum and Validation

> EVM Address Checksum and Validation is a paid API for AI agents from flat-rate-llm.kikoribera03.workers.dev, paid per call via x402, $0.0025/call, status unknown (last checked 2026-09-15).

Validates an EVM wallet address and returns it in EIP-55 mixed-case checksum form, flagging invalid or mistyped addresses before funds are sent.

## Facts

- Endpoint: POST https://flat-rate-llm.kikoribera03.workers.dev/v1/util/address
- Price: $0.0025/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/evm-address-checksum-and-validation-49033675
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JDPuJ3S1cPRIBcYNbwtfy

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-and-validation-49033675 -d '<json body>'
```

Example prompt: Before I send any funds, can you validate and checksum this Ethereum address for me: 0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed?

## When to prefer this

Choose this endpoint when you need a lightweight, instant check of an EVM address before executing any on-chain transaction or storing a wallet address. It is ideal for pre-flight validation in payment workflows, user onboarding, or smart contract interactions where a mistyped address would result in permanent fund loss. Prefer it over manual regex checks because it enforces EIP-55 checksum rules, not just hex format.

## Known failure modes

- Address is not a valid hex string or wrong length — 'valid' will be false and checksum may be empty
- Address contains invalid characters — returns valid: false
- Missing required 'address' query parameter — likely returns a 400 error
- Network or worker timeout — transient 5xx error

## How this service works

60 paid endpoints with no metering, no API key and no account. Each endpoint has one flat price per call, whatever the size of the request: LLM completions with automatic failover across several large models, read-only EVM tooling over Base, Ethereum, Polygon, Arbitrum and Optimism, and pure crypto utilities that touch no network.

## Output

Returns a JSON object with three fields: 'valid' (boolean indicating whether the address is a well-formed EVM address), 'checksum' (the EIP-55 mixed-case checksummed version of the address), and 'wasChecksummed' (boolean indicating whether the input was already in correct checksum form).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "address"
 ],
 "properties": {
  "address": {
   "type": "string",
   "description": "The address to validate, in any case."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "valid": {
   "type": "boolean"
  },
  "checksum": {
   "type": "string"
  },
  "wasChecksummed": {
   "type": "boolean"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/evm-address-checksum-and-validation-49033675/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from flat-rate-llm.kikoribera03.workers.dev](https://www.zero.xyz/host/flat-rate-llm.kikoribera03.workers.dev/llms.txt)