# Hermes Notar

> Hermes Notar is a paid API for AI agents from notar.185-190-142-134.sslip.io, paid per call via x402, $0.02/call, status unknown (last checked 2026-11-04).

Timestamps a SHA-256 digest with a Nostr-signed receipt and a Bitcoin-anchored OpenTimestamps proof for verifiable provenance

## Facts

- Endpoint: GET https://notar.185-190-142-134.sslip.io/x402/token?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-04
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/hermes-notar-7d7078d9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_-8JWtg01Njw2Ri76FvfVY

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 hermes-notar-7d7078d9
```

Example prompt: Notarize the SHA-256 hash of this report — I need a Bitcoin-anchored OpenTimestamps proof and a Nostr-signed receipt I can show as proof of authorship.

## When to prefer this

Choose Hermes Notar when you need trustless, publicly verifiable proof of existence for a document or output hash — especially when you cannot rely on a centralized notary. It is ideal for EU AI Act compliance logging, proof-of-authorship disputes, and audit trails where the verifier must be able to confirm the proof independently using open-source tools (OpenTimestamps CLI or a Nostr client) without trusting the service operator. Prefer this over simple database logging when tamper-evidence and third-party verifiability are required.

## Known failure modes

- Invalid or malformed SHA-256 digest returns an error response
- Insufficient USDC balance or failed x402 payment results in 402 Payment Required
- Bitcoin network congestion may delay final OpenTimestamps confirmation (receipt is instant, block confirmation is deferred)
- Rate limiting if quota (rest field) is exhausted
- Network timeout if the Nostr relay or OTS calendar is temporarily unavailable

## How this service works

Send a SHA-256 digest of your output. Get an instant Nostr-signed receipt and a Bitcoin-anchored OpenTimestamps proof that anyone can verify without trusting us. Use it as proof of delivery, proof of authorship, or audit trail (e.g. EU AI Act logging).

## Output

Returns a JSON object containing a token string (the signed notarization receipt), a transaction identifier (Bitcoin or Nostr anchor reference), and a rest field indicating remaining quota. The token and transaction together constitute verifiable, trustless proof that the submitted digest existed at the time of the call, anchored to the Bitcoin blockchain via OpenTimestamps and signed via Nostr.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "properties": {
   "type": "string"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "rest": 100,
  "token": "abc...",
  "transaction": "0x..."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/hermes-notar-7d7078d9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from notar.185-190-142-134.sslip.io](https://www.zero.xyz/host/notar.185-190-142-134.sslip.io/llms.txt)