Aether-X Port Congestion Oracle
Predictive port congestion, ETA delay and freight volatility signals for 16 global ports
Real-time data of any marine and inland vessel equipped with AIS tracking system.
AIS Hub API is a free Transportation API that requires apiKey authentication, is only available over HTTP and has unconfirmed CORS support.
AISHub members have access to AISHub aggregated AIS data via our API and receive real time data in XML, JSON or CSV format.
Details from aishub.net.

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Predictive port congestion, ETA delay and freight volatility signals for 16 global ports
Geospatial data for Mexico City public transport system (Metro, Metrobús, Cablebús, RTP, etc.)
The AIS Hub API is provided by AISHub (aishub.net). AISHub members have access to AISHub aggregated AIS data via our API and receive real time data in XML, JSON or CSV format.
Yes. The AIS Hub 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.
Yes. The AIS Hub API uses apiKey authentication, so you need to register for credentials before making requests.
CORS support for the AIS Hub API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
No. The AIS Hub API is only available over plain HTTP, which browsers block on HTTPS sites. Call it from a server instead.