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Api Endpoint

Hashing, HMAC & Checksum Suite

Give this API any text or binary data and it returns its fingerprint under whichever hash algorithms you choose - SHA-256, SHA-512, MD5, BLAKE2, CRC32 and more. It also signs data with a secret key (HMAC) and safely verifies whether an incoming signature matches, using a timing-safe comparison. Language models cannot hash: they emit a string of the right length and character set that is simply wrong, so every webhook check built on a guessed hash is silently broken.

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Offering

Provider
hash-hmac.underscoredone.com
Method
POST
Offering type
Api Endpoint
Transport type
http
Category
Security
Delivery
Not provided
Pricing model
Not provided
x402 version
2

Endpoint context

URL
https://hash-hmac.underscoredone.com/hash
MIME type
application/json
First seen
2026-10-16T01:50:10.647Z
Last seen
Tags
sha256 hash, hash, HMAC, hmac signature, verify hmac signature

Website

Payment pricing

x402 payment terms are the authoritative price for calling this endpoint.

Payment option 1
0.01 USDC
Atomic price: 10000 · Network: eip155:8453 · Asset: USDC · Scheme: exact
Payment option 2
0.01 USDC
Atomic price: 10000 · Network: solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp · Asset: USDC · Scheme: exact
Raw x402 terms
[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "10000",
    "payTo": "0xE9740820225B3918b4ddd1292C7cA4Ca0e2C2F08"
  },
  {
    "scheme": "exact",
    "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
    "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
    "amount": "10000",
    "payTo": "8ugAWAXDB8V18kiUrGZTq1oMvU3C6Fxs8hfC6rvzQT3b"
  }
]

Observed health

Status
Reachable
Latest latency
97 ms
Average latency
110 ms
HTTP status
405
Last checked
Reachability
100% over 5 checks

Latency is measured to the first response headers. A reachable result does not verify response accuracy or merchant identity.

Input schema

{
  "type": "object",
  "properties": {
    "type": {
      "type": "string",
      "const": "http"
    },
    "method": {
      "type": "string",
      "enum": [
        "POST",
        "PUT",
        "PATCH"
      ]
    },
    "bodyType": {
      "type": "string",
      "enum": [
        "json",
        "form-data",
        "text"
      ]
    },
    "body": {
      "type": "object",
      "properties": {
        "input": {
          "type": "string",
          "description": "The text or data you want to hash. For binary data, base64-encode it first and set input_encoding to 'base64'."
        },
        "input_encoding": {
          "type": "string",
          "description": "How the input is encoded. Use 'utf-8' for normal text (default) or 'base64' for binary data."
        },
        "algorithms": {
          "type": "array",
          "description": "Which fingerprint methods to use. Choose any of: md5, sha1, sha224, sha256, sha384, sha512, sha3_256, sha3_512, blake2b, blake2s, crc32, adler32. You may list several at once."
        },
        "output_encoding": {
          "type": "string",
          "description": "How to display the resulting fingerprints. Choose 'hex' (default, lowercase letters and numbers), 'base64', or 'base64url' (safe for URLs)."
        },
        "hmac": {
          "type": "object",
          "description": "Optional. Include this block to sign data or verify a signature. Contains: mode ('sign' or 'verify'), algorithm (md5, sha1, sha256, or sha512), key (your full secret key as a string), and expected_signature (only needed when mode is 'verify')."
        }
      },
      "required": [
        "input",
        "algorithms"
      ],
      "additionalProperties": false
    }
  },
  "required": [
    "type",
    "method",
    "bodyType",
    "body"
  ],
  "additionalProperties": false
}

Output schema

{
  "type": "object",
  "properties": {
    "type": {
      "type": "string"
    },
    "example": {
      "type": "object",
      "properties": {
        "api_version": {
          "type": "string"
        },
        "input_bytes": {
          "type": "integer"
        },
        "digests": {
          "type": "object",
          "additionalProperties": true
        },
        "hmac": {
          "type": "object",
          "additionalProperties": true
        }
      },
      "required": [
        "api_version",
        "input_bytes",
        "digests",
        "hmac"
      ]
    }
  },
  "required": [
    "type"
  ]
}