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The Zamp API provides endpoints for calculating sales tax, managing transactions, validating addresses, and accessing filing and registration data. New to the API? Start with the sales tax API documentation overview or the Quickstart. Base URL: https://api.zamp.com

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Authentication

All API endpoints are authenticated using bearer tokens in the Authorization header.
See the Authentication guide for details on obtaining a token.

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Conventions

Errors

Status codes and error response formats.

Pagination

Work with cursor-paginated list responses.

Transaction object

The shared shape behind calculations and transactions.

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Available endpoints

Addresses

Validate addresses before collecting taxes

Calculations

Calculate tax due on transactions in real-time

Companies

Retrieve company information associated with your API key

Transactions

Create, retrieve, update, and delete transactions

Tax Codes

List all product tax codes supported by Zamp

Registrations

View state tax registrations for your company

Filings

Access tax filing history and documents
Last modified on August 21, 2026