Complyt vs Zamp

Complyt is an API and web sales tax engine for business transactions. Its API accepts line items, shipping addresses, transaction status, and related details, then returns a calculated tax amount and applicable rate. The US rate endpoint currently supports supplied addresses in the United States, while documentation describes VAT and global tax for international transactions. Customer records can be classified as retail, reseller, or marketplace, and those categories can affect taxability and nexus thresholds. Complyt distinguishes estimates, which do not count toward nexus thresholds, from invoices, which do. It offers nexus monitoring and an exemptions endpoint for exempt customers. Address Validation checks US addresses against official postal databases and returns suggested matches with confidence scores. Xero integration calculates line-level US sales tax using jurisdiction, nexus, exemptions, and product type; Xero tax calculation requires a US shipping or billing address. API access uses a client ID and secret to obtain a bearer token that expires after 24 hours. Pricing is on request.

Zamp has no write-up on Specifiction yet; its figures are above.