Hash

Cryptographic hash of a text string. Algorithms: sha256 (default), sha512, sha1, md5. Returns hex and base64 digests.

Input

Field	Type	Description
text *	string	Text to hash (max 100KB)
algo	string	sha256 | sha512 | sha1 | md5

Example output

{
  "algo": "sha256",
  "hex": "b94d27…",
  "base64": "uU0n…"
}

Try it - see the 402 challenge (free)

curl -i -X POST https://agent402.tools/api/hash \
  -H "Content-Type: application/json" \
  -d '{"text":"hello world","algo":"sha256"}'

The response is HTTP 402 Payment Required with exact payment requirements. Any x402 v2 client pays automatically and retries:

Paid call (JavaScript agent)

import { wrapFetchWithPayment } from "@x402/fetch";
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(KEY) });
const payFetch = wrapFetchWithPayment(fetch, client);

const res = await payFetch("https://agent402.tools/api/hash", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    "text": "hello world",
    "algo": "sha256"
  }),
});

No wallet? Pay with compute

This is a pure-CPU tool, so an agent without a wallet can pay with proof-of-work instead of USDC: fetch a challenge, solve the sha256 puzzle (16 leading zero bits - a fraction of a second of CPU, no money, no AI tokens), and resend with the X-Pow-Solution header.

import { createHash } from "node:crypto";
const lz = (b) => { let t = 0; for (const x of b) { if (!x) { t += 8; continue; } t += Math.clz32(x) - 24; break; } return t; };
const c = await (await fetch("https://agent402.tools/api/pow/challenge?slug=hash")).json();
let n = 0;
while (lz(createHash("sha256").update(c.challenge + ":" + n).digest()) < c.difficulty) n++;
await fetch("https://agent402.tools/api/hash", { method: "POST", headers: { "X-Pow-Solution": c.token + ":" + n, "Content-Type": "application/json" }, body: JSON.stringify({"text":"hello world","algo":"sha256"}) });

Part of these workflows

This tool is one step in 5 curated multi-tool workflows - agents can fetch the whole sequence as an MCP prompt or call https://agent402.tools/api/skill-packs/{slug}/prompt.

• Decode this blob - Hand the agent an opaque string - a JWT, a base64'd JSON payload, a gzip-encoded API response, a hex-encoded hash - and walk it through identifying what it is and unwrapping it layer by layer until it's human-readable.
• JWT forensics - Someone hands you a JWT and asks 'is this valid?' Decode without verification first to see the shape, render the time claims (iat/nbf/exp) in human time, compute exactly how long until expiry, then HMAC-verify against the secret. Optional follow-ups: decode any base64-looking custom claims, verify embedded SHA fingerprints.
• User onboarding - Take a signup form submission and run the full onboarding workup deterministically: validate the email, score the chosen password, mint a stable internal ID, derive a URL-safe handle from the display name, generate a recovery / API secret, hash the password for storage, and verify the 2FA setup code. One pass, every step a pure-CPU call.
• Webhook secure intake - The production ingest path for every incoming webhook: verify the provider signature (GitHub / Stripe / Shopify / Slack, constant-time, replay-window enforced), schema-validate the now-trusted body against the provider envelope, fingerprint the raw bytes for redelivery dedup, normalize the event timestamp to UTC + epoch, and redact PII before anything hits a log. Five pure-CPU tools - the accept-or-reject gate, run on every event.
• Server-side identity mint - The server-side identity-issuance round-trip: mint a random user-id (UUIDv4), derive a deterministic cross-system correlation-id (UUIDv5), turn the display name into a URL-safe handle, generate a one-time recovery password, hash it for storage, sign a session JWT with HMAC, and base64-encode the recovery bundle for transport. Seven pure-CPU tools - the canonical 'create-user' write path done as one deterministic pipeline.

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