# Sellat eIDAS Qualified Electronic Timestamp (RFC 3161)

> Sellat eIDAS Qualified Electronic Timestamp (RFC 3161) is a paid API for AI agents from sellat.app, paid per call via x402, $0.9/call, status unknown (last checked 2026-10-23).

Issues an EU eIDAS-qualified electronic timestamp (RFC 3161) on an existing Sellat proof, giving it full legal presumption of accuracy before EU courts and authorities under Article 41.2 eIDAS.

## Facts

- Endpoint: POST https://sellat.app/api/v2/proofs/:id/qualified?utm_source=zero.xyz
- Price: $0.9/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sellat-eidas-qualified-electronic-timestamp-rfc-3161-ddbfd007
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_f-jjwhM9gptNXiAq7Y3JI

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 sellat-eidas-qualified-electronic-timestamp-rfc-3161-ddbfd007 -d '<json body>'
```

Example prompt: Apply an eIDAS-qualified electronic timestamp (RFC 3161) to my Sellat proof with ID abc123 so the date is legally recognised before EU courts under Article 41.2 eIDAS.

## When to prefer this

Choose this endpoint when you need a timestamp that carries EU legal force — specifically the presumption of accuracy under Article 41.2 eIDAS — as opposed to a standard blockchain anchor. Use it when the proof will be presented before an EU court, regulatory authority, or in any context requiring a qualified trust service provider (QTSP) seal. If only immutability/blockchain anchoring is needed without EU legal standing, the standard Sellat proof endpoint suffices. This endpoint is the right choice for IP disputes, contractual evidence, compliance filings, and any scenario demanding legally-recognised timestamping in EU jurisdictions.

## Known failure modes

- Proof ID not found — returns 404 if the specified :id does not correspond to an existing Sellat proof
- Invalid or missing request body — returns 400 if required body fields are absent or malformed
- Payment failure — returns 402 if the $0.9 USDC x402 payment is not completed or is invalid
- Timestamp authority unavailable — may return 503 if the EU qualified trust service provider is temporarily unreachable
- Timestamp already issued — may return conflict if a qualified timestamp has already been applied to this proof ID
- Unauthorized request — returns 401 if authentication credentials are invalid or missing

## How this service works

eIDAS qualified electronic timestamp (RFC 3161 .tsr) on a Sellat proof, issued in seconds by an EU qualified trust service provider on the EU trusted list. Legal timestamp with the presumption of accuracy of date and integrity of Art. 41.2 eIDAS, recognised across the EU. Use when the date must hold before a court, authority, regulator or auditor. Call it on the proof_id from POST /proofs.

## Output

An RFC 3161 qualified timestamp token issued by an EU qualified trust service provider, attached to the specified Sellat proof. The timestamp carries the legal presumption of accuracy under Article 41.2 eIDAS, making the proof's date enforceable before EU courts and authorities. Response is typically returned within seconds.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object"
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST",
      "PUT",
      "PATCH"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "queryParams": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sellat-eidas-qualified-electronic-timestamp-rfc-3161-ddbfd007/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from sellat.app](https://www.zero.xyz/host/sellat.app/llms.txt)