# Quaderno
> Tax automation platform for SaaS, eCommerce, and digital marketplaces. Automates VAT, GST, and Sales Tax compliance.

## Primary Solutions
- [Tax Calculation](https://quaderno.io/calculation/): Real-time tax calculation for global transactions.
- [Invoicing](https://quaderno.io/invoicing/): Automated, compliant tax invoicing worldwide.
- [Reporting & Filing](https://quaderno.io/reporting-filing/): Tax reports and automated filing for VAT, GST, and US Sales Tax.
- [Checkout](https://quaderno.io/checkout/): Tax-compliant checkout forms for digital products.

## 2026 Key Tax Guides
- [United Kingdom VAT Guide](https://quaderno.io/guides/united-kingdom-vat-guide/): 2026 rules for digital services in the UK.
- [Canada GST/HST Guide](https://quaderno.io/guides/canada-gst-hst-guide/): Comprehensive guide for digital businesses in Canada.
- [EU VAT Guide](https://quaderno.io/guides/eu-vat/): Rules for selling digital goods across the European Union.
- [US Economic Nexus](https://quaderno.io/US-economic-nexus/): Guide to Sales Tax thresholds in the United States.

## Top Integrations
- [Stripe](https://quaderno.io/integrations/stripe/)
- [Shopify](https://quaderno.io/integrations/shopify/)
- [WooCommerce](https://quaderno.io/integrations/woocommerce/)
- [PayPal](https://quaderno.io/integrations/paypal/)
- [Amazon FBA](https://quaderno.io/integrations/amazon-fba/)

## Developer Resources
- [API Reference](https://quaderno.io/api/): Documentation for custom tax automation integrations.
- [Verifactu API](https://quaderno.io/es/api/verifactu/): Spanish anti-fraud tax regulation compliance.
- [TicketBAI API](https://quaderno.io/es/api/ticketbai/): Compliance for Basque Country tax regulations.

## Spanish Resources (Recursos en Español)
- [Guía Verifactu](https://quaderno.io/es/articulos/verifactu/): Normativa española sobre sistemas de facturación.
- [Cálculo de Impuestos](https://quaderno.io/es/calculo-de-impuestos/): Automatización de impuestos para negocios digitales.