Categories › Business & Finance › Accounting & invoicing
Free no-auth tools for Spain: validate IBAN, EU VAT check (VIES), Modelo 303 sums, Veri*factu dates.
Remote server: your requests and data go to api.contix.es. Claude Code: claude mcp add --transport http contix-herramientas https://api.contix.es/api/v1/mcp/herramientas · Claude app: Settings → Connectors → Add custom connector.
The tools this server listed when we connected to it, in its own words.
calculate_vat — Compute the taxable base, VAT (IVA) amount, optional recargo de equivalencia and optional IRPF withholding from an amount. By default `imporvalidate_spanish_tax_id — Two modes in one input. If `valor` is only 1-8 digits, computes the DNI check letter and returns the full 8-digit-plus-letter DNI (digits arvalidate_iban — Check whether an IBAN is well formed: country length (SWIFT IBAN registry) and ISO 13616 check digits. For Spanish IBANs also the two accouncheck_vat_number — Look up an EU VAT number in the European Commission's VIES registry. Returns what the registry says: whether the number exists and, where thcalculate_modelo_303 — Add up the boxes (casillas) of the Spanish quarterly VAT return Modelo 303 with the formulas printed on the official AEAT form: 27, 45, 46, get_obligation_dates — Deadlines from the published Spanish rules: Veri*factu (RD 1007/2023, dates of RD-ley 15/2025) and mandatory B2B e-invoicing (RD 238/2026, cNot tested by KitScout yet. When our harness runs it, pros, cons and the tasks we tried appear here, with the date and evidence.