
Auckland Transport.
Transport for Auckland, New Zealand API is a free Transportation API that requires no API key, is served over HTTPS and has unconfirmed CORS support.
The Auckland Transport developer portal allows you to explore the diverse range of APIs and transport data from Auckland Transport and NZTA.
Details from dev-portal.at.govt.nz.

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The Transport for Auckland, New Zealand API is provided by Auckland Transport developer portal (dev-portal.at.govt.nz). The Auckland Transport developer portal allows you to explore the diverse range of APIs and transport data from Auckland Transport and NZTA.
Yes. The Transport for Auckland, New Zealand API is listed in the Transportation category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
No. The Transport for Auckland, New Zealand API requires no authentication, so you can start making requests without signing up.
CORS support for the Transport for Auckland, New Zealand API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The Transport for Auckland, New Zealand API is served over HTTPS, so it's safe to use in production.