# KHOTEM Cryptographic Document Seal — Paid Verification

> KHOTEM Cryptographic Document Seal — Paid Verification is a paid API for AI agents from khotem.com, paid per call via x402, $0.1/call, status unknown (last checked 2026-09-13).

Fetches a cryptographically sealed document by ID, returning its content along with a payment-verified seal hash proving the document was retrieved and paid for.

## Facts

- Endpoint: POST https://khotem.com/api/doc/17
- Price: $0.1/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/khotem-cryptographic-document-seal-paid-verification-2e424cc9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_IS0rTmoH90wvMwl5SVHcu

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 khotem-cryptographic-document-seal-paid-verification-2e424cc9 -d '<json body>'
```

Example prompt: Can you retrieve document 17 from KHOTEM and give me the sealed, cryptographically witnessed copy — I need the content along with the SHA hash and payment seal as proof of retrieval?

## When to prefer this

Choose this endpoint when you need a tamper-evident, payment-backed cryptographic proof that a specific document was accessed at a given time — especially in audit, compliance, or legal contexts where a simple download is insufficient. It is particularly suited for no-signup, no-KYC workflows where USDC on Base is acceptable and the $0.10 per-call cost is appropriate. Prefer alternatives if you need bulk document retrieval, do not require a cryptographic seal, or cannot transact on Base.

## Known failure modes

- Payment not received or invalid — 402 response with no document returned
- Document ID does not exist — 404 or empty response
- Insufficient USDC balance on Base for the $0.10 payment
- Network or blockchain confirmation delay causing payment timeout
- Malformed request body causing 400 error

## How this service works

Paid cryptographic witness services for autonomous agents and humans: seals, attestations, verification, audit, sealed document thread. x402-native micropayments, USDC on Base / Polygon / Solana, direct on-chain verification. No accounts, no API keys, no KYC.

## Output

Returns a JSON object containing the document ID, the document content in markdown format, a 16-character SHA hex hash of the document, and a payment_seal hex string serving as a cryptographic witness that the document was retrieved under a valid USDC payment on Base.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "queryParams": {
     "type": "object",
     "properties": {},
     "description": "No input — GET returns the document after payment.",
     "additionalProperties": false
    }
   }
  },
  "output": {
   "type": "object",
   "properties": {
    "example": {
     "doc": "17",
     "sha16": "a1b2c3d4e5f60708",
     "content": "<document 17, markdown>",
     "payment_seal": "1020304050607080"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/khotem-cryptographic-document-seal-paid-verification-2e424cc9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from khotem.com](https://www.zero.xyz/host/khotem.com/llms.txt)