# ZUGFeRD Validator (remote · api.zugferd-validator.de)

Validiert E-Rechnungen (ZUGFeRD/Factur-X, XRechnung) gegen EN 16931 mit Korrekturvorschlägen.

- Trust score: 64/100 (medium)
- Change this week: +3
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-08-03

## Components

- remote · `api.zugferd-validator.de`: 64/100 (this document), [markdown](https://verifymcp.io/servers/de-zugferd-validator-validator/api.md), [page](https://verifymcp.io/servers/de-zugferd-validator-validator/api)
- npm · `zugferd-mcp-client`: 61/100, [markdown](https://verifymcp.io/servers/de-zugferd-validator-validator/zugferd-mcp-client.md), [page](https://verifymcp.io/servers/de-zugferd-validator-validator/zugferd-mcp-client)

## Channel facts

- Endpoint: `https://api.zugferd-validator.de/mcp`
- Transports: `streamable-http`
- Auth: `required`
- Version: `1.0.2`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-08-03.

- **Endpoint Security**: 57/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 4 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - HTTPS is enforced; there's no plaintext access path.
  - HSTS check failed: the Strict-Transport-Security header is absent.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 63/100
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 710 tokens (~177/item across 4 items; 4 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 27/100
  - Stability observed for 8 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### Claude

```bash
claude mcp add --transport http de-zugferd-validator-validator https://api.zugferd-validator.de/mcp
```

### Codex

```toml
[mcp_servers.de-zugferd-validator-validator]
url = "https://api.zugferd-validator.de/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "de-zugferd-validator-validator": {
      "type": "remote",
      "url": "https://api.zugferd-validator.de/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add de-zugferd-validator-validator --url https://api.zugferd-validator.de/mcp --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  de-zugferd-validator-validator:
    url: "https://api.zugferd-validator.de/mcp"
```

### Other

```json
{
  "mcpServers": {
    "de-zugferd-validator-validator": {
      "type": "http",
      "url": "https://api.zugferd-validator.de/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-08-02 (score 64, +1)

No change was recorded against any check on this day. Stability & Change Management went from 20 to 23. That category is still filling its 30-day observation window: 6 days of observed history at the previous scan, 7 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-31 (score 63, 0)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-30 (score 63, +1)

No change was recorded against any check on this day. Stability & Change Management went from 10 to 13. That category is still filling its 30-day observation window: 3 days of observed history at the previous scan, 4 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-29 (score 62, +1)

No change was recorded against any check on this day. Stability & Change Management went from 7 to 10. That category is still filling its 30-day observation window: 2 days of observed history at the previous scan, 3 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-27 (score 61, +1)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-26 (score 60)

First indexed and scored.

## MCP tools (4)

### `validate_invoice` (~115 tokens)

Validiert eine E-Rechnung (ZUGFeRD/Factur-X PDF oder XRechnung XML) gegen EN 16931 und gibt strukturierte Ergebnisse mit Korrekturvorschlägen zurück.

Input parameters:

- `file_content` (string, required): Base64-kodierter Inhalt der PDF- oder XML-Datei
- `file_type` (string, required): 'pdf' für ZUGFeRD/Factur-X, 'xml' für XRechnung
- `profile` (string): Erwartetes Profil (optional, wird automatisch erkannt)

### `extract_xml` (~53 tokens)

Extrahiert die eingebettete XML-Datei aus einem ZUGFeRD/Factur-X PDF.

Input parameters:

- `pdf_content` (string, required): Base64-kodierter Inhalt der ZUGFeRD-PDF-Datei

### `check_consistency` (~54 tokens)

Prüft ob die sichtbaren PDF-Daten mit den eingebetteten XML-Daten übereinstimmen.

Input parameters:

- `pdf_content` (string, required): Base64-kodierter Inhalt der ZUGFeRD-PDF-Datei

### `create_invoice` (~488 tokens)

Erstellt aus strukturierten Daten eine valide E-Rechnung — entweder als ZUGFeRD-PDF (PDF/A-3 mit eingebettetem XML) oder als reines XRechnung-XML (mit Leitweg-ID für B2G). Unterstützt mehrere Positionen, alle USt-Kategorien, Rabatte/Zuschläge und Zahlungsangaben. Stateless — es wird nichts gespeichert.

Input parameters:

- `allowances_charges` (array): Rabatte/Zuschläge auf Dokumentebene
- `buyer` (object, required): Käufer / Rechnungsempfänger
- `buyer_reference` (string): Leitweg-ID / Käuferreferenz (BT-10, bei XRechnung Pflicht)
- `currency` (string): Währung (Standard EUR)
- `date` (string, required): Belegdatum (YYYY-MM-DD)
- `document_type` (string): Dokumenttyp (Standard invoice). credit_note=Gutschrift/Storno, corrected=Korrektur, self_billed=Gutschriftverfahren, prepayment=Anzahlung, partial=Teilrechnung, debit_note=Belastungsanzeige. Mappt au…
- `due_date` (string): Fälligkeitsdatum (YYYY-MM-DD)
- `format` (string, required): 'zugferd' = PDF/A-3 mit eingebettetem XML, 'xrechnung' = reines XML
- `lines` (array, required): Rechnungspositionen (mindestens eine)
- `note` (string): Freitext-Hinweis
- `number` (string, required): Belegnummer
- `payment_means` (object): Zahlungsangaben (IBAN etc.)
- `payment_terms` (string): Zahlungsbedingungen (Freitext)
- `preceding_invoice` (object): Bezug auf die Ursprungsrechnung (BT-25/26) — bei Storno, Korrektur oder Gutschrift angeben
- `self_check` (boolean): Wenn true, wird die erzeugte Rechnung sofort gegen EN 16931 geprüft (langsamer). Standard: false.
- `seller` (object, required): Verkäufer / Rechnungssteller
- `seller_logo` (string): Logo als Base64 (PNG/JPG) — nur im Pro/Ultra-Tarif
- `type_code` (string): Roher UNTDID-1001-Code (überschreibt document_type; für seltene Typen wie 875-877 Bauleistung)

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/de-zugferd-validator-validator/api#diagnostics

## Score history

- 2026-08-03: 64
- 2026-08-02: 64
- 2026-08-01: 63
- 2026-07-31: 63
- 2026-07-30: 63
- 2026-07-29: 62
- 2026-07-28: 61
- 2026-07-27: 61
- 2026-07-26: 60

## Links

- Remote endpoint: https://api.zugferd-validator.de/mcp
- Authorisation metadata: https://api.zugferd-validator.de/.well-known/oauth-protected-resource/mcp
- Website: https://zugferd-validator.de/
- Changelog RSS feed: https://verifymcp.io/servers/de-zugferd-validator-validator/api/changelog.xml
- Changelog JSON feed: https://verifymcp.io/servers/de-zugferd-validator-validator/api/changelog.json
- HTML version of this page: https://verifymcp.io/servers/de-zugferd-validator-validator/api