Web page proof lookup API

Fetch a proof created earlier with proof_create by its id, to re-check its hashes, artifact links and timestamp anchor status.

freeGET /v1/proof/{id}MCP proof_getFree tool

What you get

  • The stored proof: id, URL, capture time and SHA-256 hashes
  • Links to the archived HTML (served sandboxed) and the PNG screenshot
  • The OpenTimestamps anchor and its status

Parameters

  • idstringrequiredpath

    Proof id (ULID) returned by proof_create

    pattern ^[0-9A-HJKMNP-TV-Z]{26}$

Try it

With a key, every Run is paid from your credits and the balance updates after each call. Kept only in this browser tab; sent only to this site.

Enter the id returned by proof_create. Anyone with the id can view the proof; it is free.

Proof id (ULID) returned by proof_create.

Free tool: no charge and no free-tier count.

Equivalent curl
curl "https://402check.com/v1/proof/01M5YCTV80A6V3J9N5RXW7TC8E"

Example response

Example response
{
  "id": "01M5YCTV80A6V3J9N5RXW7TC8E",
  "url": "https://example.com/page",
  "capturedAt": "2026-10-27T10:00:00.000Z",
  "sha256": {
    "html": "28c6b4d8ba18e876196fb1d376671e3be48b283f8c1fe6e2481ec62f66b9664e",
    "png": "4353a1de7e0dcc4e87350e22d5c9ee9f3e70e8ce9c31533ec991bee8870c4814"
  },
  "artifacts": {
    "html": "https://402check.com/v1/proof/01M5YCTV80A6V3J9N5RXW7TC8E/html",
    "png": "https://402check.com/v1/proof/01M5YCTV80A6V3J9N5RXW7TC8E/png"
  },
  "anchor": {
    "provider": "opentimestamps",
    "otsBase64": "APAQqrvM",
    "status": "pending"
  }
}

The proof created in the proof_create example, read back.

HTTP

Request (free tier, no key)
curl "https://402check.com/v1/proof/01M5YCTV80A6V3J9N5RXW7TC8E"

MCP

tools/call request
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "proof_get",
    "arguments": {
      "id": "01M5YCTV80A6V3J9N5RXW7TC8E"
    }
  }
}

Endpoint https://402check.com/mcp. Setup for Cursor, Claude and other clients is in the docs.

Source and limits

Data from 402check proof store (Cloudflare R2).

  • Free and outside the free-tier count
  • Unknown ids answer 404 not_found; malformed ids 400 invalid_id

Questions

How much does it cost?

Nothing. proof_get is free and does not count against the free tier.

Do I need an account?

No. Call it without credentials on the free tier, pay per call with x402 over HTTP, or send a prepaid rk_ key bought by card.

Where do the artifacts live?

At /v1/proof/{id}/html and /v1/proof/{id}/png, also free.