# AgentResolver Keccak256 Hash

> AgentResolver Keccak256 Hash is a paid API for AI agents from agentresolver.vercel.app, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-18).

Computes the Keccak-256 cryptographic hash of an input string, returning the digest as a 0x-prefixed hex value.

## Facts

- Endpoint: POST https://agentresolver.vercel.app/api/keccak256
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-18
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentresolver-keccak256-hash-f6f7cdbd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Cv54HJNUzXvvnz_MPtFGo

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 agentresolver-keccak256-hash-f6f7cdbd -d '<json body>'
```

Example prompt: Can you compute the keccak256 hash of the string 'Transfer(address,address,uint256)' using utf8 encoding? I need the 0x-prefixed hex digest.

## When to prefer this

Choose this endpoint when you need a pay-per-call, serverless Keccak-256 hash computation — especially for Ethereum/EVM use cases like computing function selectors, event topic hashes, or verifying Solidity keccak256 outputs. Prefer it over running a local library when operating in a sandboxed agent environment without native crypto access. Not suited for SHA-256, MD5, or non-Keccak hashing.

## Known failure modes

- Missing required 'input' field returns a validation error
- Invalid encoding value (not 'utf8' or 'hex') causes a schema error
- Malformed hex input when encoding is 'hex' may cause a parsing error
- Payment of 0.004 USDC via x402 required; missing payment returns 402 response

## How this service works

Verify an x402 endpoint before paying: live payTo, USDC quote, network, asset, resource binding, TLS and endpoint safety for $0.001 on Base or Solana.

## Output

Returns a JSON object containing: the algorithm name ('keccak256'), the encoding used (utf8 or hex), the number of input bytes processed, and the 32-byte digest as a 0x-prefixed 64-character lowercase hex string (e.g. '0xabc123...').

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "input": {
   "type": "string",
   "maxLength": 131072
  },
  "encoding": {
   "enum": [
    "utf8",
    "hex"
   ],
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {}
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentresolver-keccak256-hash-f6f7cdbd/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentresolver.vercel.app](https://www.zero.xyz/host/agentresolver.vercel.app/llms.txt)