How to map custom fields from a checkout page to a financial platform to automate VAT calculations by country?
Business & Payments, Automation & No-Code
Identify the checkout fields that affect VAT, such as country, shipping address, and product type. Align these fields with the inputs required by the VAT engine.
Define consistent country codes and data formats to ensure reliable rate lookups. Prepare a minimal data model that keeps mappings maintainable.
Implement a lightweight workflow that computes VAT per order and stores results for audit and reporting.
Who is this for?
- Developers integrating checkout with a VAT engine
- Finance and tax teams validating cross-border tax flows
- E-commerce platform maintainers implementing regional checkout variants
- Product teams designing country-specific checkout experiences
Before you start
- Access to a VAT calculation engine or endpoint
- Defined list of required fields from checkout
- Initial data mapping draft or spec
General Process (How it works)
- Identify input fields affecting VAT List checkout fields that influence VAT: country, shipping address, product type, and customer tax status.
- Normalize country and region codes Map country names to standard codes and normalize region/state data for reliable tax lookup.
- Define engine mappings Create a field-by-field map from checkout data to VAT engine inputs.
- Validate required data Ensure all required fields exist and have valid formats before calculation.
- Calculate VAT by country Use tax tables or a free API to compute VAT per jurisdiction.
- Store and audit results Persist calculated VAT alongside order data for reporting and audits.
- Handle edge cases and updates Plan for exemptions, rate changes, and data drift; document decisions.
Common beginner mistakes
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