This is a custom component for Home Assistant which uses the Metlink opendata API to obtain realtime departure info for Greater Wellington public transport, which can then be displayed on your Home Assistant dashboard or used in automations.

The integration can be installed using HACS. If you prefer to instal manually, copy custom_components/metlink to your installation's config/custom_components directory.

After installing the custom component, you still need to configure it before it will do anything.

The integration can be added from the Integrations configuration screen.

API keys can be obtained by registering on the Metlink Developer Portal. Be sure to subscribe to the "Metlink Open Data API". Currently this is the only API they offer, and is free, but is still unsubscribed by default.

stop_id for Train and Cable Car stops is a 3 to 4 character alphabetic code, and for bus and ferry stops, is a 4 digit numeric code. The IDs are on bus stop signs, or can be looked up on the Metlink main web site.

If your stop is busy with multiple routes, you can filter by route and/or destination. Currently exact matches are expected and only a single route or destination can be specified, though the destination does check the name as well as the stop id for a match, but some of the names that come through the API are abbreviated in ways that do not match the main web site so stop id will be more reliable. The destination filter is only available on the final destination, not any intermediate stops.

Each stop will create a sensor in Home Assistant, which will return the next departure time as its status.

It will also return attributes for departure time, service, service name, destination name, stop id for the destination, status, service alerts and more. The duplication of departure time in the attributes makes more sense when there is more than one result being returned.

If more than 1 result is requested in num_departures, the attributes will be suffixed with a number for second and subsequent departures.

Stop IDs sometimes behave differently, E.g. if your start stop ID is NAEN and the final destination is WELL, it doesn't work but it works with WELL1 as the final destination. To ensure that you have the correct final destination Stop ID, create a sensor without a final destination and get the final destination which shows up in the attributes.

Thanks to Greater Wellington Regional Council for making their data available via an open API, and the following users who have submitted improvements to this Home Assistant integration.

• messum for identifying that train stations are not always 4 characters, and fixing that, and contributing documentation to advise on the new train station naming complexity where major stations have numbered source/destination ids.
• Me-sudoer for finding an issue with the HA iOS app's different handling of timestamps than web and Android.
• meringu for contributing service alert support.