invowerk MCP

An official MCP server provided by invowerk that enables AI agents to validate, create, and manage German and European e-invoices. It supports formats such as ZUGFeRD, Factur-X, XRechnung, and Peppol BIS, allowing users to check compliance and generate structured electronic documents directly through tool calls.

Endpoint and access

No sign-in to connect and list tools. Individual tools may still need a vendor account, credentials, or permissions; check the documented prerequisites.

Vendor evidenceStreamable HTTPNo sign-inEndpoint checked 2026-11-06Operated by invowerk

You need:Auth: send an `X-API-Key` header (create keys after signing in).Tool calls use the same API key and credits as the REST API.

MCP endpoint (Streamable HTTP)

https://api.invowerk.dev/mcp/

Vendor documentation

What its tools do

6 tools, grouped by the hints the server advertises. Hints are self-declared, not verified behavior.

6 of 6 have a description · 6 of 6 declare behavior hints · 6 of 6 with parameters document them all

Checks and signals

Each line is separate evidence, not a trust score.

Passed Endpoint answered the live check · Nov 6, 2026, 2:45 PM UTC
Passed Official MCP Registry namespace is tied to invowerk.dev · Nov 6, 2026, 2:37 PM UTC
Passed Endpoint is on the registry namespace domain · Nov 6, 2026, 2:37 PM UTC
Availability 1 of 1 checks passed in 30 days

What you can do with it

Validate ZUGFeRD and Factur-X invoice compliance
Generate XRechnung and Peppol BIS e-invoices
Check e-invoicing requirements by country
Create PDF invoices with embedded XML data

Source and maintenance

Vendor evidenceRegistry 1.0.1

mcp-registry: dev.invowerk/xrechnung-e-invoice-validator@1.0.1 Source repository Project website

Maintenance checked: Nov 6, 2026, 2:37 PM UTC

Protocol and capabilities

Server: invowerk 1
MCP protocol negotiated in check: 2025-11-25
Tools: 6 advertised
Resources: 0 advertised
Resource templates: 0 advertised
Prompts: 0 advertised

Server-advertised capabilities

{
  "tools": {
    "listChanged": true
  },
  "logging": {},
  "prompts": {
    "listChanged": true
  },
  "resources": {
    "subscribe": false,
    "listChanged": true
  },
  "extensions": {
    "io.modelcontextprotocol/ui": {}
  },
  "experimental": {}
}

Tools

6 advertised

validate_invoice — Check an e-invoice

Advertised by the server during the last successful anonymous check.

Advertised read-onlyOpen-world

Check an e-invoice against EN 16931 and German rules. Input: `invoice_base64` is the base64 of an XML invoice (UBL or CII) or a ZUGFeRD / Factur-X PDF, at most 4 MB decoded; or pass the file as a download link in `file`. `explain=true` adds an explanation to findings whose rule has one, in `lang` ("de" or "en"). `valid` is the result. For XRechnung the KoSIT validator decides. If it is unreachable, invowerk's own check with the same rules decides, `verdict_source` is "local" and `official_degraded` is true. `disagreement` is true when both ran and differ. `findings` lists each problem with `rule_id`, `severity` and `message`; pass the codes to `explain_errors` (free). `pdfa_verdict` is the PDF/A check of a PDF. `hints` never change `valid`. Unreadable input returns a finding, not an error. It fails with an error when the check is busy (`engine_busy`), ran longer than 20 s (`engine_timeout`) or the XML has more than 100,000 elements (`document_too_complex`). Credits: 1 per call.

validate_invoice input schema

{
  "type": "object",
  "properties": {
    "file": {
      "type": "object",
      "default": null,
      "required": [
        "download_url",
        "file_id"
      ],
      "properties": {
        "file_id": {
          "type": "string",
          "description": "An identifier for the file. ChatGPT sets it; other clients may pass any label, such as the file name."
        },
        "file_name": {
          "type": "string"
        },
        "mime_type": {
          "type": "string"
        },
        "download_url": {
          "type": "string",
          "description": "A public https URL of the file."
        }
      },
      "description": "The file as a download link, instead of `invoice_base64`. In ChatGPT, pass the user's uploaded file here. Other clients can set `download_url` to a public https URL."
    },
    "lang": {
      "enum": [
        "de",
        "en"
      ],
      "type": "string",
      "default": "de",
      "description": "Language of the explanations: \"de\" (default) or \"en\"."
    },
    "explain": {
      "type": "boolean",
      "default": false,
      "description": "true adds an explanation to each finding whose rule has one."
    },
    "invoice_base64": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "The invoice file, base64-encoded. At most 4 MB decoded."
    }
  },
  "additionalProperties": false
}

validate_invoice output schema

{
  "type": "object",
  "additionalProperties": true
}

validate_invoice annotations

{
  "title": "Check an e-invoice",
  "readOnlyHint": true,
  "openWorldHint": true
}

render_invoice — Render an e-invoice as HTML

Advertised by the server during the last successful anonymous check.

Advertised read-onlyOpen-world

Render an XML e-invoice (UBL or CII, e.g. XRechnung) as a readable HTML page. invowerk uses the KoSIT XRechnung visualization. Use it to show a person what an e-invoice contains. Input: `invoice_base64` is the base64 of the XML, at most 4 MB decoded, or pass the file as a download link in `file`. PDFs are not accepted. `lang` sets the label language, "de" (default) or "en". Returns `html` (a complete HTML document), `lang`, `flavor` (e.g. "xrechnung") and `syntax` (e.g. "ubl_invoice"). A file that is not an XML invoice, malformed XML or XML with a DOCTYPE fails with an error message, and so does a busy (`engine_busy`) or overrunning (`engine_timeout`) render. Credits: 1 per call.

render_invoice input schema

{
  "type": "object",
  "properties": {
    "file": {
      "type": "object",
      "default": null,
      "required": [
        "download_url",
        "file_id"
      ],
      "properties": {
        "file_id": {
          "type": "string",
          "description": "An identifier for the file. ChatGPT sets it; other clients may pass any label, such as the file name."
        },
        "file_name": {
          "type": "string"
        },
        "mime_type": {
          "type": "string"
        },
        "download_url": {
          "type": "string",
          "description": "A public https URL of the file."
        }
      },
      "description": "The file as a download link, instead of `invoice_base64`. In ChatGPT, pass the user's uploaded file here. Other clients can set `download_url` to a public https URL."
    },
    "lang": {
      "enum": [
        "de",
        "en"
      ],
      "type": "string",
      "default": "de",
      "description": "Language of the labels: \"de\" (default) or \"en\"."
    },
    "invoice_base64": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "The invoice file, base64-encoded. At most 4 MB decoded."
    }
  },
  "additionalProperties": false
}

render_invoice output schema

{
  "type": "object",
  "additionalProperties": true
}

render_invoice annotations

{
  "title": "Render an e-invoice as HTML",
  "readOnlyHint": true,
  "openWorldHint": true
}

explain_errors — Explain error codes

Advertised by the server during the last successful anonymous check.

Advertised read-only

Explain rule codes in plain language. Works without an API key. Covers the codes of `validate_invoice` findings and hints: EN 16931, XRechnung, ZUGFeRD and invowerk's own hint codes (IW-*). Input: `codes` is a list of one or more codes, e.g. ["BR-CO-18", "BR-DE-21"]. Duplicates are removed. `lang` is "de" (default) or "en". Returns `lang` and `explanations`. Each explanation has `title`, `meaning`, `causes`, `fixes`, `severity`, `standard`, `bt_refs`, `xpath_hints` and `explain_url` (the German page for the code). If any code is unknown, the call fails and names the unknown codes. Credits: free. This tool is not metered.

explain_errors input schema

{
  "type": "object",
  "required": [
    "codes"
  ],
  "properties": {
    "lang": {
      "enum": [
        "de",
        "en"
      ],
      "type": "string",
      "default": "de",
      "description": "Language of the explanations: \"de\" (default) or \"en\"."
    },
    "codes": {
      "type": "array",
      "items": {
        "type": "string"
      },
      "description": "One or more rule codes from validate_invoice, e.g. [\"BR-CO-18\", \"BR-DE-21\"]."
    }
  },
  "additionalProperties": false
}

explain_errors output schema

{
  "type": "object",
  "additionalProperties": true
}

explain_errors annotations

{
  "title": "Explain error codes",
  "readOnlyHint": true,
  "openWorldHint": false
}

generate_invoice — Create an e-invoice from JSON

Advertised by the server during the last successful anonymous check.

Advertised read-only

Create a valid EN 16931 e-invoice (UBL or CII XML) from JSON. Input: `invoice` is a JSON object keyed on EN 16931 Business Terms, the same schema as `POST /v1/generate`, at most 4 MB. Main fields: `syntax` ("ubl" default, or "cii"), `flavor` ("en16931" default, or "xrechnung", which requires `buyer_reference`, the Leitweg-ID BT-10, and `payment_iban`), `invoice_number`, `issue_date` (YYYY-MM-DD), `currency`, `seller`, `buyer`, `lines`, `tax_breakdown`, `totals`. invowerk writes your amounts as given. It does not compute or correct them. Input that breaks an EN 16931 or XRechnung rule returns an error naming each rule, e.g. BT-112 = BT-109 + BT-110 (BR-CO-15). Dates are YYYY-MM-DD, amounts go up to 999,999,999.99. Returns `xml`, `syntax`, `flavor` and `self_validation`. invowerk checks the XML before answering and never returns an invalid document. Invalid input, or XML that fails the check, returns an error, as does a busy (`engine_busy`) or overrunning (`engine_timeout`) generate. Credits: 5 per call.

generate_invoice input schema

{
  "type": "object",
  "required": [
    "invoice"
  ],
  "properties": {
    "invoice": {
      "type": "object",
      "description": "The invoice as a JSON object keyed on EN 16931 Business Terms, the schema of POST /v1/generate and of parse_invoice's `model`: syntax, flavor, invoice_number, issue_date, currency, seller, buyer, lines, tax_breakdown, totals.",
      "additionalProperties": true
    }
  },
  "additionalProperties": false
}

generate_invoice output schema

{
  "type": "object",
  "additionalProperties": true
}

generate_invoice annotations

{
  "title": "Create an e-invoice from JSON",
  "readOnlyHint": true,
  "openWorldHint": false
}

parse_invoice — Read an e-invoice into JSON

Advertised by the server during the last successful anonymous check.

Advertised read-onlyOpen-world

Read an existing e-invoice into JSON keyed on EN 16931 Business Terms. The JSON is the input format of `generate_invoice`, so you can edit it and create the invoice again. Input: `invoice_base64` is the base64 of an XML invoice (UBL or CII) or a ZUGFeRD / Factur-X PDF, at most 4 MB decoded; or pass the file as a download link in `file`. A PDF may have at most 500 pages and 16 attachments. Returns `model` (the invoice as JSON), `detection` (`syntax`, `flavor`, `customization_id`) and `source` ("xml" or "pdf-embedded"). A file that cannot be read fails with an error that starts with an error code, e.g. a PDF without embedded XML, a UBL credit note, malformed XML, or a busy (`engine_busy`) or overrunning (`engine_timeout`) read. Credits: 2 per call.

parse_invoice input schema

{
  "type": "object",
  "properties": {
    "file": {
      "type": "object",
      "default": null,
      "required": [
        "download_url",
        "file_id"
      ],
      "properties": {
        "file_id": {
          "type": "string",
          "description": "An identifier for the file. ChatGPT sets it; other clients may pass any label, such as the file name."
        },
        "file_name": {
          "type": "string"
        },
        "mime_type": {
          "type": "string"
        },
        "download_url": {
          "type": "string",
          "description": "A public https URL of the file."
        }
      },
      "description": "The file as a download link, instead of `invoice_base64`. In ChatGPT, pass the user's uploaded file here. Other clients can set `download_url` to a public https URL."
    },
    "invoice_base64": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "The invoice file, base64-encoded. At most 4 MB decoded."
    }
  },
  "additionalProperties": false
}

parse_invoice output schema

{
  "type": "object",
  "additionalProperties": true
}

parse_invoice annotations

{
  "title": "Read an e-invoice into JSON",
  "readOnlyHint": true,
  "openWorldHint": true
}

convert_invoice — Convert an e-invoice between UBL and CII

Advertised by the server during the last successful anonymous check.

Advertised read-onlyOpen-world

Convert an e-invoice to UBL or CII. The result is checked before it is returned. Input: `invoice_base64` is the base64 of an XML invoice or a ZUGFeRD / Factur-X PDF, at most 4 MB decoded; or pass the file as a download link in `file`. `target_syntax` is "ubl" or "cii". `target_flavor` is optional, "en16931" or "xrechnung"; without it the flavor of the source is kept. Returns `xml`, `syntax`, `flavor` and `self_validation` (`valid`, `finding_count`). invowerk checks the converted XML before answering and never returns an invalid document. Input that cannot be read or converted fails with an error message. Credits: 3 per call.

convert_invoice input schema

{
  "type": "object",
  "required": [
    "target_syntax"
  ],
  "properties": {
    "file": {
      "type": "object",
      "default": null,
      "required": [
        "download_url",
        "file_id"
      ],
      "properties": {
        "file_id": {
          "type": "string",
          "description": "An identifier for the file. ChatGPT sets it; other clients may pass any label, such as the file name."
        },
        "file_name": {
          "type": "string"
        },
        "mime_type": {
          "type": "string"
        },
        "download_url": {
          "type": "string",
          "description": "A public https URL of the file."
        }
      },
      "description": "The file as a download link, instead of `invoice_base64`. In ChatGPT, pass the user's uploaded file here. Other clients can set `download_url` to a public https URL."
    },
    "target_flavor": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "Optional: \"en16931\" or \"xrechnung\". Without it the flavor of the source is kept."
    },
    "target_syntax": {
      "type": "string",
      "description": "Syntax to convert to: \"ubl\" or \"cii\"."
    },
    "invoice_base64": {
      "anyOf": [
        {
          "type": "string"
        },
        {
          "type": "null"
        }
      ],
      "default": null,
      "description": "The invoice file, base64-encoded. At most 4 MB decoded."
    }
  },
  "additionalProperties": false
}

convert_invoice output schema

{
  "type": "object",
  "additionalProperties": true
}

convert_invoice annotations

{
  "title": "Convert an e-invoice between UBL and CII",
  "readOnlyHint": true,
  "openWorldHint": true
}

Prompts

0 advertised

No prompt definitions available.

Resources

0 advertised

No resource definitions available.

30-day availability

Aggregated from read-only remote checks; this is not a tool-execution or security guarantee.

Successful checks: 1 of 1 (100%)
Average latency: 1859 ms
95th percentile latency: 1859 ms

Maintenance history

Public check and source-refresh events. Editorial and ownership records remain private.

Nov 6, 2026, 2:45 PM UTC · probe · passed · 1859 ms · metadata changed · 6 tool(s), 0 resource(s), 0 resource template(s), 0 prompt(s)

Connect from your client

Each snippet registers the same endpoint; pick the client you use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Claude Code

Run this once in a terminal. It registers the remote server. Use --scope project to write .mcp.json for the repo.

Claude Code configuration

claude mcp add --transport http invowerk-mcp https://api.invowerk.dev/mcp/

Codex

Run this once. Codex stores MCP servers in ~/.codex/config.toml (or .codex/config.toml in a trusted project).

Codex configuration

codex mcp add invowerk-mcp --url https://api.invowerk.dev/mcp/

Cursor

Merge this server into .cursor/mcp.json in your project, then enable invowerk-mcp in your MCP settings.

Cursor configuration

{
  "mcpServers": {
    "invowerk-mcp": {
      "url": "https://api.invowerk.dev/mcp/"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure).

Cline configuration

{
  "mcpServers": {
    "invowerk-mcp": {
      "type": "streamableHttp",
      "url": "https://api.invowerk.dev/mcp/",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start invowerk-mcp and inspect its tools.

VS Code configuration

{
  "servers": {
    "invowerk-mcp": {
      "type": "http",
      "url": "https://api.invowerk.dev/mcp/"
    }
  }
}

Gemini CLI

Run this once. It writes .gemini/settings.json in the current project; pass --scope user for ~/.gemini/settings.json.

Gemini CLI configuration

gemini mcp add --transport http invowerk-mcp https://api.invowerk.dev/mcp/

Claude Desktop

Open Claude Settings > Connectors > Add custom connector, enter this server URL and enable it for the conversation. This is a manual remote-connector handoff, not a desktop JSON configuration.

Claude Desktop configuration

https://api.invowerk.dev/mcp/

Windsurf

Merge this into ~/.codeium/windsurf/mcp_config.json, then refresh MCP in Cascade. Windsurf remote servers use serverUrl, not url.

Windsurf configuration

{
  "mcpServers": {
    "invowerk-mcp": {
      "serverUrl": "https://api.invowerk.dev/mcp/"
    }
  }
}

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invowerk MCP

Endpoint and access

What its tools do

Read-only (6)

Checks and signals

What you can do with it

Source and maintenance

Protocol and capabilities

Tools

Prompts

Resources

30-day availability

Maintenance history

Connect from your client

Claude Code

Codex

Cursor

Cline

VS Code

Gemini CLI

Claude Desktop

Windsurf

Let your agent find its tools

Other commerce servers

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