invowerk

Name: invowerk
Author: invowerk-dev

by invowerk-devversion 1.0.1i★ 0iRuns in the cloud

Registry namedev.invowerk/xrechnung-e-invoice-validator

How to install

What it does

E-invoice checker for ZUGFeRD, Factur-X, XRechnung and Peppol BIS. Free web tool, API and MCP.

Connects Runs in the cloud
Account or key Works without a key · add X-API-Key if you have one (often raises limits)
Category Accounting, finance & tax

Install

Pick the AI app you use, then copy the settings.

Passed 5/5 checks · What you ask goes through the maker’s server (api.invowerk.dev)

First: which AI do you use?

ClaudeWeb · app · phoneChatGPTWebClaude CodeTerminalCursorCode editorVS CodeCode editorOtherOther apps

Pick your app and the steps appear below.

Works with Claude · about 2 min

No key, nothing to install · Set it up once on claude.ai or the desktop app, then use it in chat · free accounts can add 1 · on Team/Enterprise an Owner adds it

Open Claude’s Connectors page
CustomizeConnectors
Done
Click “+ Add” → “Add custom connector” and fill in these 2 fields
Copy each value into the field with the same name in Claude, then click Continue
Name · Nameinvowerk
Remote MCP server URL · Addresshttps://api.invowerk.dev/mcp/
Leave Authentication as Claude detected it, then click Add
Done
Turn it on in a chat
+Connectorsinvowerk
Done
Try it
Use invowerk and tell me what you can do for me, then show me one thing
✓ If Claude says it is using invowerk or shows a invowerk tool in the answer, you are connected

Menu names checked against Anthropic’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Works with ChatGPT on business plans only

ChatGPT Business, Enterprise or Edu on the web, added by a workspace admin or owner · On Free, Plus or Pro: your ChatGPT plan cannot connect MCP yet

Open ChatGPT’s add-MCP page on the web
Plugins+Add custom MCP server
Done
Fill in the name and address
Enter a name, paste the address under Connection, tick the risk warning and click Create as a plugin
Name · Nameinvowerk
Connection · Addresshttps://api.invowerk.dev/mcp/
Done
Pick invowerk in a chat
Start a new chat and pick invowerk from your plugins before typing
Done
Try it
Use invowerk and tell me what you can do for me, then show me one thing
✓ If ChatGPT says it is using invowerk or shows a invowerk tool in the answer, you are connected

Menu names checked against OpenAI’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Works with Claude Code · about 2 min

No key, nothing to install

Open Terminal
Mac: press Command+Space and type Terminal · Windows: open PowerShell
Done

Paste this command and press Enter

claude mcp add --transport http --scope user xrechnung-e-invoice-validator https://api.invowerk.dev/mcp/

Done

Type /mcp in Claude Code
You should see invowerk listed as connected
Done
Try it
Use invowerk and tell me what you can do for me, then show me one thing
✓ If Claude Code says it is using invowerk or shows a invowerk tool in the answer, you are connected

Menu names checked against Anthropic’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Works with Cursor · about 2 min

No key, nothing to install

Click this button to open Cursor
Open in Cursor
Cursor asks you to confirm; click Install
Done
Open the AI chat in Cursor in Agent mode
Done
Try it
Use invowerk and tell me what you can do for me, then show me one thing
✓ If Cursor says it is using invowerk or shows a invowerk tool in the answer, you are connected

Menu names checked against Cursor’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Works with VS Code · about 2 min

No key, nothing to install

Click this button to open VS Code
Open in VS Code
VS Code asks you to confirm; click Install
Done
Open the AI chat in VS Code in Agent mode
Done
Try it
Use invowerk and tell me what you can do for me, then show me one thing
✓ If VS Code says it is using invowerk or shows a invowerk tool in the answer, you are connected

Menu names checked against VS Code’s help page on Nov 11, 2026 · your screen may differ slightly by app version

Other apps that use MCP, such as Windsurf, Zed or Gemini CLI, each add servers differently. See how in the app list.

See every app that uses MCP →

Address for apps that connect over the web

Addresshttps://api.invowerk.dev/mcp/

JSON settings are under “For developers” below

Stuck? Ask people who use invowerk💬 Discussion →

For developers: Terminal commands and JSON settings

Over the web

Claude Code

claude mcp add --transport http --scope user xrechnung-e-invoice-validator https://api.invowerk.dev/mcp/

Cursor (~/.cursor/mcp.json)

{
  "mcpServers": {
    "xrechnung-e-invoice-validator": {
      "url": "https://api.invowerk.dev/mcp/"
    }
  }
}

VS Code (mcp.json)

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

Values you fill in

X-API-Key secret HTTP header
Optional API key; the anonymous tier works without it

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

At a glance

GitHub stars i: 0
Downloads per weeki: Not on npm/PyPI
Verified domain: ✓ invowerk.dev
Licence i: MIT
Connection: Runs in the cloud
Transport: streamable-http
Latest versioni: 1.0.1
Categoryi: Accounting, finance & tax
Published to registryi: Oct 5, 2026
Code last changedi: Nov 8, 2026
Maker: invowerk-dev
Repo: invowerk-dev/invowerk
Website: invowerk.dev
Registry status: Active

Which apps can use it

Based on how this server connects and on each app’s own docs, checked Nov 10, 2026.

Connect over the internet in

Claude ChatGPT Goose LM Studio Msty Studio Cherry Studio Cursor VS Code + GitHub Copilot Visual Studio Windsurf (Devin Desktop)Zed Kiro Cline Continue JetBrains AI Assistant Claude Code Codex CLI Gemini CLI OpenCode nodecode Warp LibreChat Open WebUI Raycast

All apps, with pros and cons →

What it can do

Tool names and descriptions exactly as the server reported them on Nov 8, 2026. The maker wrote them, not us; we show them as plain text.

validate_invoice
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 h
render_invoice
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 downloa
explain_errors
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 a
generate_invoice
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", wh
parse_invoice
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
convert_invoice
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_fl

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 12, 2026

✓ Pass
Maker matches the repo
The registry name was verified against the domain invowerk.dev (the registry checks domain ownership)
✓ Pass
Still maintained
Code last changed 4 days ago
✓ Pass
Has a licence
Uses MIT
✓ Pass
Endpoint responds
Responded in 176 ms (HTTP 200)
– Not applicable
Sign-in with OAuth
No sign-in needed
✓ Pass
No hidden instructions in tool descriptions
Read 6 tool descriptions and found no hidden instructions to the AI

Discussion

Ask, share a tip or report that it does not work. Sorted by what people marked helpful.

No posts yet. Be the first to ask or share.

Posts here are written by users, not the PopNx team.

User reviews

No reviews yet

Compared with others in Accounting, finance & taxi

More stars than 0% of the other 3151 servers in this category
Published to the registry more recently than 44% of the other 3151 servers in this category
Basic checks equal to or better than 100% of the other 3151 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is invowerk safe?

It passed 5 of 5 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs in the maker’s cloud. Connect over the internet with nothing to install, but what you send passes through the maker’s servers.

Is it still maintained?

The GitHub repo last changed 4 days ago, and the latest version (1.0.1) reached the registry 38 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT Business and above.

What can I use instead?

In the same category: CCXT, Finance Toolkit, AKQuant

Others in the same category

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Reading a card:↓ Downloads per weeki★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

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AKQuant

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

invowerk

German e-invoices: create ZUGFeRD PDFs and XRechnung, check ZUGFeRD/Factur-X, XRechnung (KoSIT) and Peppol BIS. Free tool, API, MCP.

invowerk creates and checks e-invoices. In the browser it creates ZUGFeRD PDFs and XRechnung from a form and checks each file before download. It checks ZUGFeRD 2.5.2 and Factur-X 1.09.2 PDFs, XRechnung 3.0.2 (UBL and CII) and Peppol BIS Billing 3.0.21. XRechnung goes through the KoSIT validator; PDFs are also checked for PDF/A. Each check returns a report with the file's SHA-256, rule sets and result. Invoices are processed in memory, not stored. Free web tool; REST API and MCP server with 500 free credits a month.

Quickstart

Check an e-invoice in one call. The anonymous tier needs no key; add -H "X-API-Key: $INVOWERK_API_KEY" for your plan's limits.

curl -sO https://invowerk.dev/app-static/demo/beispiel-xrechnung.xml

curl -F file=@beispiel-xrechnung.xml https://api.invowerk.dev/v1/validate

"valid": true, "verdict_source": "official", "official_verdict": "valid", "scenario": {"config": "kosit-xrechnung", "name": "EN16931 XRechnung (UBL Invoice)"}, "detection": {"kind": "xml", "syntax": "ubl_invoice", "flavor": "xrechnung"}, "errors": {"format": [], "business_rules": [], "carrier": []}, "findings": [], "evidence": {"document_sha256": "259e3eff…", "checked_at": "2026-10-01T22:36:49Z"} }

The same call takes a ZUGFeRD or Factur-X PDF. A failed check is still HTTP 200, with valid: false and each problem in findings.

Use it from

MCP server

Streamable-HTTP endpoint: https://api.invowerk.dev/mcp/ — the anonymous tier works without a key; an API key raises the limits.

Claude Code:

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

Claude Code: /plugin marketplace add invowerk-dev/invowerk then /plugin install invowerk@invowerk (set INVOWERK_API_KEY for your key).

Cursor / Windsurf / Cline / Claude Desktop:

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

One-click installs for every client: https://invowerk.dev/connect

Integrations (n8n, Zapier, Make, Dify, SDKs and templates): https://github.com/invowerk-dev/invowerk-integrations

Templates

Ready-made workflows: https://invowerk.dev/templates

API

Base URL https://api.invowerk.dev/ — authenticate with an X-API-Key header; anonymous calls work at a lower rate limit.

About the files here

.claude-plugin/ — Claude Code plugin, with this repo as its own marketplace.
.mcp.json — the MCP server the Claude Code plugin connects to.
gemini-extension.json — Gemini CLI extension manifest.
glama.json — Glama server claim (names the maintainer).
mcp.json — Agent Plugins 1.0 MCP server config.
plugin.json — Agent Plugins 1.0 plugin manifest.
server.json — the entry in the official MCP Registry.
skills/ — an Agent Skill (agentskills.io SKILL.md) for skill galleries.

invowerk

What it does

Install

Open Claude’s Connectors page

Click “+ Add” → “Add custom connector” and fill in these 2 fields

Turn it on in a chat

Try it

Open ChatGPT’s add-MCP page on the web

Fill in the name and address

Pick invowerk in a chat

Try it

Open Terminal

Paste this command and press Enter

Type /mcp in Claude Code

Try it

Click this button to open Cursor

Open the AI chat in Cursor in Agent mode

Try it

Click this button to open VS Code

Open the AI chat in VS Code in Agent mode

Try it

Over the web

Values you fill in

At a glance

Which apps can use it

Related guides

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Discussion

User reviews

Compared with others in Accounting, finance & taxi

Common questions

Others in the same category

CCXT

Finance Toolkit

AKQuant

README from the maker

invowerk

Quickstart

Use it from

MCP server

Templates

Links

API

About the files here