Gusto is a payroll management service that facilitates tax calculations, tax filings, payments, direct deposits, and checks, independent contractor payments, and other functions. The GustoAPI allows users to integrate third-party systems with the Gusto platform. An account is required with service, and OAuth 2.0 is used for authentication. Gusto was formerly known as ZenPayroll. Gusto is not accepting new integrations currently, and API access is for existing partners.