Westpac QuickStream REST API
First-party Westpac payment API (beyond CDR). QuickStream is Westpac's online payment gateway; its public REST API v1 exposes Transactions, Customers, Accounts, Credit Cards, Recurring Payments, PayIDs, Single-Use-Tokens, Payment Files, PayTo Agreements, Businesses and API Keys resources for card and account payment processing. Uses HTTP Basic auth with a secret or publishable API key at api.quickstream.westpac.com.au/rest/v1 (test host api.quickstream.support.qvalent.com). Fully documented publicly but NO downloadable OpenAPI/Swagger is published (reference docs and Postman-based exploration only), so no machine-readable spec is wired.