contix

Spanish invoicing with Veri*factu from your AI assistant: create and finalize invoices, customers, payments, expenses, recurring invoices and Modelo 303 figures. 63 tools, OAuth 2.1 or API key.

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Hosted MCP Server

npx add-mcp 'https://api.contix.es/api/v1/mcp/herramientas'

Installs into Claude Code, Codex, Cursor and more

Documentation

contix

contix MCP server: Spanish invoicing with Veri*factu

Run your Spanish invoicing from Claude, ChatGPT, Cursor or any MCP client: customers, invoices with the Veri*factu hash chain and QR, payments, expenses, quotes, recurring invoices, Facturae/FACe for the public administration, Modelo 303/349/390 figures, and a workspace for your accountant (gestoría). Hosted by contix, nothing to install. This repository holds the public metadata; the server code is not open source.

https://api.contix.es/api/v1/mcp

Streamable HTTP · OAuth 2.1 (dynamic client registration + PKCE) or API key (Authorization: Bearer cx_live_…, read-only or read/write) · needs a contix account (30-day trial). Irreversible steps, like finalizing an invoice into the Veri*factu chain, ask for explicit confirmation.

Setup for Claude, ChatGPT and Cursor: contix.es/mcp · API reference: contix.es/api · OpenAPI: https://api.contix.es/openapi.json

All 63 tools

Invoices

  • create_invoice: Create draft invoice
  • update_invoice: Update draft invoice
  • get_invoice: Get invoice details · read-only
  • list_invoices: List invoices · read-only
  • finalize_invoice: Finalize invoice (irreversible) · asks for confirmation / irreversible
  • clone_invoice: Clone invoice to draft
  • rectify_invoice: Rectify invoice (Veri*factu)
  • cancel_invoice: Cancel/annul invoice (irreversible) · asks for confirmation / irreversible
  • delete_invoice: Delete draft invoice
  • send_invoice: Send invoice by email

Customers and payments

  • list_customers: List customers · read-only
  • get_customer: Get customer · read-only
  • create_customer: Create customer
  • update_customer: Update customer
  • record_payment: Record a payment
  • list_payments: List payments of an invoice · read-only
  • get_account_statement: Customer account statement · read-only
  • send_reminder: Send payment reminder
  • list_reminders_sent: List reminders sent · read-only
  • check_vat_number: Check an EU VAT number (VIES) · read-only

Quotes and recurring invoices

  • list_quotes: List quotes · read-only
  • create_quote: Create quote
  • send_quote: Send a quote by email
  • convert_quote_to_invoice: Convert quote to invoice
  • list_recurring: List recurring profiles · read-only
  • create_recurring: Create recurring profile
  • generate_recurring: Generate invoice from recurring profile

Expenses and suppliers

  • list_expenses: List expenses · read-only
  • create_expense: Create expense
  • update_expense: Edit expense
  • delete_expense: Delete expense
  • list_suppliers: List suppliers · read-only

Tax figures and public administration

  • get_modelo: Get AEAT tax model (modelo) · read-only
  • check_period: Check a period before handing it over · read-only
  • get_invoice_facturae: Get Facturae XML (B2G) · read-only
  • submit_invoice_to_face: Submit invoice to FACe (B2G)
  • get_face_status: Get FACe status (B2G) · read-only
  • calculate_modelo_303: Sum the Spanish VAT return (Modelo 303) · read-only
  • get_obligation_dates: Veri*factu and e-invoicing deadlines (Spain) · read-only
  • validate_iban: Validate an IBAN · read-only

Settings

  • get_invoice_series: Get invoice series/numbering · read-only
  • set_invoice_series: Set invoice series/numbering
  • get_invoice_defaults: Get invoice defaults · read-only
  • set_invoice_defaults: Set invoice defaults
  • get_invoice_footer: Get invoice footer · read-only
  • set_invoice_footer: Set invoice footer
  • get_product_groups: Get product groups · read-only
  • set_product_groups: Set product groups
  • get_subscription_status: Get subscription/trial status · read-only

For accountants (gestorías) and their clients

  • invite_gestoria: Invite your gestoría
  • gestoria_listar_mandantes: List gestoría clients · read-only
  • gestoria_invitar_mandante: Invite a gestoría client
  • gestoria_abrir_mandante: Open a gestoría client
  • gestoria_resumen_mandante: Gestoría client: figures for a period · read-only
  • gestoria_facturas_mandante: Gestoría client: list invoices · read-only
  • gestoria_gastos_mandante: Gestoría client: list expenses · read-only
  • gestoria_revision_mandante: Gestoría client: what is missing · read-only
  • gestoria_export: Export all gestoría clients · read-only
  • gestoria_certificado_mandante: Compliance certificate for a gestoría client · read-only
  • gestoria_comisiones: Gestoría earnings from contix · read-only
  • gestoria_cierre_config: Quarter-close reminders: current settings · read-only
  • gestoria_cierre_configurar: Quarter-close reminders: change settings
  • gestoria_cierre_vista_previa: Quarter-close reminder: preview for one client · read-only

The MCP server, the REST API and the web panel run on the same engine. The live list is tools/list on the endpoint.

Free tools without an account

A second, smaller server with four read-only tools, no account and no auth:

https://api.contix.es/api/v1/mcp/herramientas
  • validate_iban: IBAN check (country length, ISO 13616 check digits); for Spanish IBANs also the account check digits and the bank with its BIC from the Banco de España registry. A 20-digit Spanish account number is converted to its IBAN.
  • check_vat_number: EU VAT number lookup in the European Commission's VIES registry.
  • calculate_modelo_303: sums the boxes of the Spanish quarterly VAT return with the formulas of the official AEAT form.
  • get_obligation_dates: Veri*factu and mandatory B2B e-invoicing dates from the published rules.

Same tools as a REST API without key: https://api.contix.es/api/v1/herramientas (docs). In the browser: contix.es/herramientas.

Configuration

{
  "mcpServers": {
    "contix": { "type": "http", "url": "https://api.contix.es/api/v1/mcp" },
    "contix-herramientas": { "type": "http", "url": "https://api.contix.es/api/v1/mcp/herramientas" }
  }
}

Clients without OAuth: add "headers": { "Authorization": "Bearer cx_live_YOUR_KEY" } to the contix entry; the key is created in the contix panel under Ajustes → API keys.

Registry

Both servers are in the Official MCP Registry as es.contix/contix and es.contix/herramientas (the server.json files here are copies).

Contact

martin@contix.es · Privacy · Terms

contix is software that issues invoices, not a tax advisory service. Results are what you enter, computed; what is correct for your case you decide with your gestoría.