Marketplace · API · x402

hash-hmac.underscoredone.com/hash

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.

Endpointhttps://hash-hmac.underscoredone.com/hash
Trust✓ Verified callable · 100% uptime over 1 checks · ~209 ms
PricingPay per call with x402, no account. Call it to get an exact quote before paying.
networkeip155:8453
schemeexact
pay to0xE9740820225B3918b4ddd1292C7cA4Ca0e2C2F08
methodPOST
last updated2026-11-09T12:05:04.532Z

Use it

Call it (an x402 client pays automatically)

curl -i https://hash-hmac.underscoredone.com/hash
# 402 reply -> sign PAYMENT-REQUIRED with an x402 client (e.g. @x402/fetch) -> retry with PAYMENT-SIGNATURE

This listing as JSON

curl https://aipaygen.com/v1/catalog/api/x402-3e56760dace70db6

Search the whole marketplace from your agent (MCP)

{
  "mcpServers": {
    "aipaygen": {
      "url": "https://aipaygen.com/mcp"
    }
  }
}