# finmath ETH Address Checksum

> finmath ETH Address Checksum is a paid API for AI agents from finmath.qzqh5rrbkz.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-13).

Converts an Ethereum address to its EIP-55 checksummed (mixed-case) canonical form

## Facts

- Endpoint: POST https://finmath.qzqh5rrbkz.workers.dev/v1/eth_address_checksum
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/finmath-eth-address-checksum-97afb83f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__WHb5NZfEatuYAFa2ZX2G

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 finmath-eth-address-checksum-97afb83f -d '<json body>'
```

Example prompt: Can you checksum this Ethereum address for me so it's in proper EIP-55 format? The address is 0xd8da6bf26964af9d7eed9e03e53415d37aa96045

## When to prefer this

Use this endpoint when you need a deterministically correct EIP-55 checksummed Ethereum address and cannot trust an LLM to perform the Keccak-256 hashing required by the standard. Prefer this over ad-hoc LLM address formatting whenever you are passing an address to a smart contract, wallet, or system that validates checksum casing.

## Known failure modes

- Invalid Ethereum address format — not a 40-hex-character string after 0x prefix returns an error
- Missing required 'address' field in request body returns a validation error
- Non-hex characters in address cause parsing failure
- Payment not provided or insufficient USDC causes 402 Payment Required response

## How this service works

Deterministic finance and crypto math for AI agents: TradFi (NPV, IRR, XIRR, Black-Scholes + Greeks, bonds, VaR, Sharpe) and DeFi (impermanent loss, perp liquidation, funding, Uniswap v3, health factor, cost basis). Exact, model-free arithmetic that LLMs get wrong — priced per call in USDC.

## Output

Returns a result object containing the EIP-55 checksummed Ethereum address (mixed-case hex string) and a meta object with call metadata. The checksummed address has capital letters inserted at specific positions per the Keccak-256 hash of the lowercase address, making it self-validating.

## Example request

```json
{
 "address": "0x1234567890123456789012345678901234567890"
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "address"
 ],
 "properties": {
  "address": {
   "type": "string",
   "description": "address"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "result",
  "meta"
 ],
 "properties": {
  "meta": {
   "type": "object"
  },
  "result": {}
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/finmath-eth-address-checksum-97afb83f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from finmath.qzqh5rrbkz.workers.dev](https://www.zero.xyz/host/finmath.qzqh5rrbkz.workers.dev/llms.txt)