tax-calculation

Sales tax and VAT calculation at checkout applies nexus-aware rate selection across multiple jurisdictions, returning real-time estimates and transaction breakdowns before payment. It validates EU VAT numbers via VIES for reverse-charge and supports product-level tax codes.

Sales tax calculation works with Shopify, WooCommerce, BigCommerce, Stripe Tax, TaxJar, and Avalara. It integrates platform-native engines and custom headless checkouts to apply jurisdiction-specific rules and persist provider transaction codes for reconciliation.

Tax transactions follow an estimate-then-commit lifecycle where non-committed estimates display during checkout, commit after payment for filing, and void on cancellations. This workflow persists provider transaction codes for accountants and automated filings.

Nexus-aware tax calculation determines whether tax must be collected based on physical or economic nexus, applying jurisdiction-specific rules. It is needed when expanding sales into new US states and the EU to ensure legally accurate tax collection.

EU VAT number validation via VIES for reverse-charge executes during the checkout estimate step if a customer provides a VAT number. It verifies the number and adjusts the tax calculation to comply with EU reverse-charge rules.

Avalara AvaTax and TaxJar provide real-time calculations and filing support within the checkout workflow. They apply nexus-aware rate selection, commit transactions after payment, and persist transaction codes for automated filings.