# KHOTEM Attest — Notary & Session Verification

> KHOTEM Attest — Notary & Session Verification is a paid API for AI agents from khotem.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-15).

Looks up and attests a transaction hash, SHA-256 digest, or timestamp stamp via a SEAL notary audit, paid with USDC on Base.

## Facts

- Endpoint: POST https://khotem.com/api/attest
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/khotem-attest-notary-session-verification-ce0f3137
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Rs9xrrYd07wswq4Zvra16

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-attest-notary-session-verification-ce0f3137 -d '<json body>'
```

Example prompt: Can you verify this SHA-256 hash against the KHOTEM notary and tell me if it has a valid attestation seal: a3f1c2d4e5b6789012345678abcdef1234567890abcdef1234567890abcdef12?

## When to prefer this

Use this endpoint when you need a lightweight, no-signup, pay-per-call notary lookup for transaction hashes, SHA-256 document digests, or session stamps on the Base blockchain. It is ideal for agents that need instant cryptographic attestation without any identity verification or registration overhead. Prefer it over traditional notary services when cost-per-call ($0.02 USDC) and permissionless access matter.

## Known failure modes

- Reference not found in notary — returns not-found or null attestation
- Invalid format for ref (not a valid txHash, SHA-256, or stamp) — returns validation error
- Payment failure on Base network — call not processed
- Network timeout or upstream SEAL notary unavailable — returns service 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 the attestation or notary audit result for the given reference — including whether the hash, transaction, or stamp has a valid SEAL record, along with any associated timestamp and notary metadata.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "ref"
 ],
 "properties": {
  "ref": {
   "type": "string",
   "description": "txHash (0x+64 hex) / sha256 (64 hex) / stamp (16 hex) — exact match"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "entry": {
  "ts": "2026-08-24T12:00:00.000Z",
  "event": "seal",
  "sha256": "e3b0c4…"
 },
 "attest": "CONFIRMED",
 "attest_seal": "a1b2c3d4e5f60708",
 "payment_seal": "1020304050607080"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/khotem-attest-notary-session-verification-ce0f3137/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)