EU E-Invoice Builder — connector documentation

MCP endpoint: https://eu-einvoice-builder.connectorbay.com/mcp
REST API: POST https://eu-einvoice-builder.connectorbay.com/v1/tools/{tool_name}, described by the OpenAPI 3.1 spec at https://eu-einvoice-builder.connectorbay.com/openapi.json
Transport: Streamable HTTP, stateless, MCP specification 2025-06-18 or later
Authentication: none required. An optional Authorization: Bearer <key> raises rate limits.
Health: https://eu-einvoice-builder.connectorbay.com/health · Tool schemas: https://eu-einvoice-builder.connectorbay.com/tools.json
Publisher: Unify Dynamics LLC · connectorbay.com/eu-einvoice-builder · agent@connectorbay.com

What EU E-Invoice Builder is for

EU E-Invoice Builder turns plain invoice data (parties, lines, VAT categories, payment means) into a Peppol BIS Billing 3.0 UBL Invoice or Credit Note XML draft. build_ubl_invoice and build_ubl_credit_note compute the totals and the VAT breakdown with the EN 16931 rounding rules, insert the CustomizationID and ProfileID, refuse input that breaks a business rule (rule ids such as BR-CO-15 or BR-AE-02 are quoted) and return the XML with a structural check. compute_totals returns line, tax and payable totals with the rounding policy stated. pick_vat_category lists what EN 16931 requires for each VAT category code (standard, zero, exempt, reverse charge, intra-community supply, export, not subject to VAT), with the exemption reason (VATEX) codes it takes, and list_vatex_codes searches the VATEX list of the May 2026 Peppol release. invoice_input_guide shows the JSON shape with a worked example and business-term numbers, and peppol_ids returns the identifiers to insert. The output is a draft for review: nothing is sent, signed or stored, national CIUS (XRechnung, Factur-X, FatturaPA) differ, and the category choice is the issuer's decision to confirm with an adviser.

Ask your assistant things like:

"Turn this invoice data into a Peppol e-invoice XML draft I can review"
"Make a credit note for my earlier invoice as a Peppol draft"
"What are the VAT total and the amount due for these invoice lines?"
"What does an invoice need if the sale is a reverse-charge supply to a business in another country?"
"Which VATEX code is the intra-community supply exemption?"
"Which CustomizationID and EndpointID schemeID go into a Peppol BIS 3.0 invoice?"

What it does

build_ubl_invoice: Create a Peppol BIS Billing 3.0 UBL Invoice XML draft from invoice JSON, with computed totals, VAT breakdown and a structural check.
build_ubl_credit_note: Create a Peppol BIS Billing 3.0 UBL Credit Note XML draft from the same JSON shape (type code 381 by default).
compute_totals: Line, tax and payable totals and the VAT breakdown of an invoice, with the rounding policy stated.
pick_vat_category: What EN 16931 requires for each VAT category code and which VATEX exemption codes fit, for a described situation.
list_vatex_codes: Search the VAT exemption reason (VATEX) code list of the May 2026 Peppol release.
invoice_input_guide: The invoice JSON shape accepted by the builders, with business-term (BT) numbers per field and a worked minimal example.
peppol_ids: The CustomizationID, ProfileID and EndpointID elements to insert in a Peppol BIS Billing 3.0 document.

Data sources

Reference data from official sources (docs.peppol.eu, ec.europa.eu, github.com); every answer states its source, date and validity period.

What it is not

EU E-Invoice Builder is independent; not affiliated with, endorsed by or operated by any government body, central bank, standards body or scheme operator. Names of rails, schemes and standards are used only to say what a tool works with. It is read-only: it never sends, pays, files or signs anything for you, and it never looks up private individuals.

Not advice. General information only, not legal, tax, accounting or payment advice. EU E-Invoice Builder is an independent tool: it is not affiliated with, endorsed by or operated by any government body, central bank, standards body or scheme operator. Rates, thresholds and rules change; check the cited official source and confirm with a qualified professional before you rely on a result.

Built for: European Union. Languages: English.

Tools

Look up & validate

list_vatex_codes — Search the VAT exemption reason (VATEX) code list of the May 2026 Peppol release. Use for "Which VATEX code is the intra-community supply exemption?". Args: query.

Calculate

compute_totals — Line, tax and payable totals and the VAT breakdown of an invoice, with the rounding policy stated. Use for "What are the VAT total and amount due for these invoice lines?". Args: invoice, rounding.

Build & format

build_ubl_invoice — Create a Peppol BIS Billing 3.0 UBL Invoice XML draft from invoice JSON, with computed totals, VAT breakdown and a structural check. Use for "Turn this invoice data into a Peppol e-invoice XML draft I can review". Args: invoice.

build_ubl_credit_note — Create a Peppol BIS Billing 3.0 UBL Credit Note XML draft from the same JSON shape (type code 381 by default). Use for "Make a credit note for invoice INV-2026-001 as a Peppol e-invoice draft". Args: invoice.

Reference & guides

pick_vat_category — What EN 16931 requires for each VAT category code and which VATEX exemption codes fit, for a described situation. Use for "What does an invoice need if the supply is a reverse-charge supply?". Args: situation.

invoice_input_guide — The invoice JSON shape accepted by the builders, with business-term (BT) numbers per field and a worked minimal example. Use for "What fields do I need to give to make a Peppol invoice?".

peppol_ids — The CustomizationID, ProfileID and EndpointID elements to insert in a Peppol BIS Billing 3.0 document. Use for "Which CustomizationID and EndpointID schemeID do I put in the XML?". Args: endpoint_scheme, endpoint_value.

Conventions

Read-only. Every tool reads public data or computes; nothing is written anywhere and nothing about the user is stored.
Result envelope. ok: true with data, or ok: false with a structured error (bad_input, not_found, upstream_error). degraded lists optional sources that were unreachable.
Rate limits. Free tier 60 tool calls/minute and 300/day per user (keyed on the user identifier supplied by the host agent, else client IP); Pro keys raise this. Over-limit calls return HTTP 429 with Retry-After. initialize and tools/list are never counted.

Support

agent@connectorbay.com · connectorbay.com/eu-einvoice-builder/support