ZUGFeRD Validator
REMOTE · API.ZUGFERD-VALIDATOR.DE · 2 COMPONENTS · SCANNED SEP 25
Validiert E-Rechnungen (ZUGFeRD/Factur-X, XRechnung) gegen EN 16931 mit Korrekturvorschlägen.
Available components
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. How we score → Why this is hard to score →
Endpoint Security57
- The endpoint's TLS certificate is valid, in date, and uses a strong key. View diagnostics → Pass
- Authorisation not fully verified: no authorisation is required to call this server, and 5 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe. See how to fix → View diagnostics → Unverified
- HTTPS is enforced; there's no plaintext access path. View diagnostics → Pass
- HSTS check failed: the Strict-Transport-Security header is absent. See how to fix → View diagnostics → Fail
- DNSSEC check failed: this domain isn't protected by DNSSEC. See how to fix → View diagnostics → Fail
Transport & Reachability100
- Verified streamable-http transport via a live MCP handshake. View diagnostics → Pass
Schema Quality & AI Usability64
- AI-judged instruction clarity (good).Pass
- Context-footprint check failed: tool/resource definitions use about 1026 tokens (~205/item across 5 items; 5 tools + 0 resources), over budget; trim descriptions and params. See how to fix → Fail
- Usage-examples check failed: none of the tools include examples. See how to fix → Fail
Stability & Change Management100
- No destabilizing schema changes in the last 30 days.Pass
Tool Coverage100
- 100% of tools have a non-trivial description (not blank, and not just the tool's name).Pass
- 100% of tool parameters carry a description.Pass
Tool Safety100
- No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.Pass
- We read all 5 captured tool definition(s), and no name or description among them implies an irreversible operation.Pass
- An AI judge read all 5 captured unit(s) of tool text and found none that tries to manipulate the model reading it.Pass
Capabilities100
- Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.Pass
How do I install the ZUGFeRD Validator MCP server?
ZUGFeRD Validator is a hosted endpoint at https://api.zugferd-validator.de/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.
remote · api.zugferd-validator.de
claude mcp add --transport http de-zugferd-validator-validator 'https://api.zugferd-validator.de/mcp'
{
"mcpServers": {
"de-zugferd-validator-validator": {
"url": "https://api.zugferd-validator.de/mcp"
}
}
} {
"servers": {
"de-zugferd-validator-validator": {
"type": "http",
"url": "https://api.zugferd-validator.de/mcp"
}
}
} [mcp_servers.de-zugferd-validator-validator] url = "https://api.zugferd-validator.de/mcp"
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"de-zugferd-validator-validator": {
"type": "remote",
"url": "https://api.zugferd-validator.de/mcp",
"enabled": true
}
}
} openclaw mcp add de-zugferd-validator-validator --url 'https://api.zugferd-validator.de/mcp' --transport streamable-http
mcp_servers:
de-zugferd-validator-validator:
url: "https://api.zugferd-validator.de/mcp" {
"McpServers": {
"de-zugferd-validator-validator": {
"Transport": "http",
"Url": "https://api.zugferd-validator.de/mcp"
}
}
} assistant mcp add de-zugferd-validator-validator -t streamable-http -u 'https://api.zugferd-validator.de/mcp'
{
"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.
Every change we have recorded for this component, newest first. Security-relevant changes are always shown. ▲ marks a change for the better, ▼ a change for the worse; unmarked changes are neutral.
- 25 Sept 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 29 Aug 26 −1
- Schema quality: 801 → 1026 ▼ functional
- New tool “validation_report” functional
- 26 Aug 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 25 Aug 26 0
- Stability: 0.97 → pass security
- 14 Aug 26 0
- Schema quality: 177 → 200 ▼ functional
- “create_invoice” added an optional parameter “billing_period” cosmetic
- “create_invoice” added an optional parameter “delivery_date” cosmetic
- “create_invoice” reworded the description of “seller” cosmetic
- “create_invoice” made “seller” optional cosmetic
- 11 Aug 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 31 Jul 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
- 27 Jul 26 0
- We updated how we score, so this day's move reflects our rubric, not a change to the server See what changed → functional
Diagnostic detail from the automated scan of this channel: what the scanner observed at each step, so you can see exactly where a check passed or failed. It is informational only and never changes the trust score.
Captured 25 Sept 2026 · Probed https://api.zugferd-validator.de/mcp
TLS valid
Negotiated TLS 1.3 with TLS_AES_128_GCM_SHA256 .
| Subject | Issuer | Valid from | Valid until | Key | Signature | Serial |
|---|---|---|---|---|---|---|
| CN=zugferd-validator.de | CN=YE1,O=Let's Encrypt,C=US | 7 Aug 2026 | 5 Nov 2026 | ECDSA 256 | ECDSA-SHA384 | 62e1cda2cdc2ab52b7a6d54830d93fb1ffa |
| SANs: api.zugferd-validator.de, docs.zugferd-validator.de, www.zugferd-validator.de, zugferd-validator.de | ||||||
| CN=YE1,O=Let's Encrypt,C=US (CA) | CN=Root YE,O=ISRG,C=US | 3 Sept 2025 | 2 Sept 2028 | ECDSA 384 | ECDSA-SHA384 | 5ddd70dd31f801c85c186a7a04b80afe |
| CN=Root YE,O=ISRG,C=US (CA) | CN=ISRG Root X2,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | ECDSA-SHA384 | 872165fc34b6e5fba8add5b3705fb53a |
| CN=ISRG Root X2,O=Internet Security Research Group,C=US (CA) | CN=ISRG Root X1,O=Internet Security Research Group,C=US | 13 May 2026 | 2 Sept 2032 | ECDSA 384 | SHA256-RSA | 6c8f1dc727c7117f7baf853ac980f9cd |
Background: What to check on a remote MCP endpoint →
DNSSEC insecure
Validation of api.zugferd-validator.de. — Not signed
| Zone | DS | Keys | Algorithms | Outcome |
|---|---|---|---|---|
| . | trust_anchor | 20326, 38696 | 8, 8 | Verified |
| de. | present | 26755 | 8 | Verified |
| zugferd-validator.de. | absent | Unsigned (proven) parent-signed NSEC/NSEC3 proves an unsigned delegation |
Authentication No authorisation required
The endpoint answered without asking for a token. Anyone who knows the URL can reach it.
| Result | No authorisation required |
|---|---|
| HTTP status | 200 |
| Header | Value |
|---|---|
| x-content-type-options | nosniff |
| x-frame-options | DENY |
| referrer-policy | strict-origin |
Background: How OAuth 2.1 works in the 2026 MCP spec →
Transports 2 probes
| Transport | URL | Outcome | Status | Location |
|---|---|---|---|---|
| streamable-http | https://api.zugferd-validator.de/mcp | Verified | 200 | |
| http (plaintext) | http://api.zugferd-validator.de/mcp | HTTPS enforced | 301 | https://api.zugferd-validator.de/mcp |
The tools this component advertises to a client, with an estimated token cost for each. Expand a tool to see its parameters and schema. The per-tool counts are indicative and are not scored directly; the schema's total context footprint is one signal in Schema Quality & AI Usability. A tool's description is untrusted text the model reads on every call, which is what makes this list a security surface and not just an inventory: how tool poisoning works →
check_consistency ~54
Prüft ob die sichtbaren PDF-Daten mit den eingebetteten XML-Daten übereinstimmen.
| Name | Type | Req | Description |
|---|---|---|---|
| pdf_content | string | yes | Base64-kodierter Inhalt der ZUGFeRD-PDF-Datei |
No output schema declared.
No examples provided.
create_invoice ~579
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.
| Name | Type | Req | Description |
|---|---|---|---|
| allowances_charges | array | – | Rabatte/Zuschläge auf Dokumentebene |
| billing_period | object | – | Leistungszeitraum (BG-14, BT-73/74) bei laufenden Leistungen, jeweils YYYY-MM-DD. Ersetzt delivery_date. |
| buyer | object | yes | Käufer / Rechnungsempfänger |
| buyer_reference | string | – | Leitweg-ID / Käuferreferenz (BT-10, bei XRechnung Pflicht) |
| currency | string | – | Währung (Standard EUR) |
| date | string | yes | Belegdatum (YYYY-MM-DD) |
| delivery_date | string | – | Leistungs-/Lieferdatum (BT-72, YYYY-MM-DD). In Deutschland Pflichtangabe; ohne Angabe gilt das Belegdatum. |
| 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 | yes | 'zugferd' = PDF/A-3 mit eingebettetem XML, 'xrechnung' = reines XML |
| lines | array | yes | Rechnungspositionen (mindestens eine) |
| note | string | – | Freitext-Hinweis |
| number | string | yes | 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 | – | Verkäufer / Rechnungssteller. Weglassen, wenn im Konto feste Absenderdaten hinterlegt sind — sie werden dann eingesetzt. |
| 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) |
No output schema declared.
No examples provided.
extract_xml ~53
Extrahiert die eingebettete XML-Datei aus einem ZUGFeRD/Factur-X PDF.
| Name | Type | Req | Description |
|---|---|---|---|
| pdf_content | string | yes | Base64-kodierter Inhalt der ZUGFeRD-PDF-Datei |
No output schema declared.
No examples provided.
validate_invoice ~115
Validiert eine E-Rechnung (ZUGFeRD/Factur-X PDF oder XRechnung XML) gegen EN 16931 und gibt strukturierte Ergebnisse mit Korrekturvorschlägen zurück.
| Name | Type | Req | Description |
|---|---|---|---|
| file_content | string | yes | Base64-kodierter Inhalt der PDF- oder XML-Datei |
| file_type | string | yes | 'pdf' für ZUGFeRD/Factur-X, 'xml' für XRechnung |
| profile | string | – | Erwartetes Profil (optional, wird automatisch erkannt) |
No output schema declared.
No examples provided.
validation_report ~225
Erzeugt aus einer E-Rechnung einen Validierungsbericht als PDF (PDF/A-3b) zum Ablegen und Weitergeben. Der Bericht nennt Ergebnis, alle Meldungen mit Regel-ID und Feld, den Prüfzeitpunkt, Format und Profil, die SHA-256-Prüfsumme der geprüften Datei sowie die Versionen der Prüfwerkzeuge. Auf Wunsch wird die geprüfte Rechnung sichtbar angehängt. Gibt das PDF base64-kodiert zurück. Ab dem Tarif Automatisieren.
| Name | Type | Req | Description |
|---|---|---|---|
| attach_source | boolean | – | Geprüfte Rechnung sichtbar anhängen (PDF-Seiten bzw. abgedruckter XML-Inhalt). Standard false. |
| file_content | string | yes | Base64-kodierter Inhalt der PDF- oder XML-Datei |
| file_name | string | – | Dateiname, der im Bericht steht. |
| file_type | string | yes | Dateityp: 'pdf' für ZUGFeRD/Factur-X, 'xml' für XRechnung/CII |
| lang | string | – | Sprache des Berichts. Standard 'de'. |
No output schema declared.
No examples provided.
What is the ZUGFeRD Validator MCP server?
ZUGFeRD Validator is an MCP server listed in the public MCP registry as de.zugferd-validator/validator. Validiert E-Rechnungen (ZUGFeRD/Factur-X, XRechnung) gegen EN 16931 mit Korrekturvorschlägen. This page covers its hosted endpoint (https://api.zugferd-validator.de/mcp).
Is the ZUGFeRD Validator MCP server safe to use?
ZUGFeRD Validator scores 76 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.
What tools does the ZUGFeRD Validator MCP server expose?
ZUGFeRD Validator exposes 5 tools: validate_invoice, extract_xml, check_consistency, create_invoice, validation_report. Their descriptions and schemas cost roughly 1,026 tokens of context every time the server is loaded.
Does the ZUGFeRD Validator MCP server require authentication?
No. We connected to ZUGFeRD Validator without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.
Is the ZUGFeRD Validator MCP server still maintained?
ZUGFeRD Validator is still listed as active in the MCP registry. We last reached this channel on 25 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.