pydelijn

An async, fully typed Python client for the De Lijn (Flemish public transport) open data API. It retrieves stops, lines, and realtime/scheduled passages.

Its primary purpose is to feed the De Lijn integration in Home Assistant.

Important: a developer account at https://data.delijn.be is required to generate a subscription key for the Core and Search open data APIs.

v2 is a breaking rewrite. The old dict-based pydelijn.api.Passages API is gone, replaced by DeLijnClient with typed models and exceptions. Docs for v1 are available in the git history.

Install

pip install pydelijn

Usage

import asyncio

from pydelijn import DeLijnClient
from pydelijn.exceptions import DeLijnError


async def main() -> None:
    api_key = "<your data.delijn.be subscription key>"

    async with DeLijnClient(api_key) as client:
        stops = await client.search_stops("Antwerpen Rooseveltplaats")
        stop = stops[0]

        passages = await client.get_passages(stop.number, max_passages=5)
        for passage in passages:
            print(
                f"Line {passage.line.public_number} to {passage.destination}: "
                f"due at {passage.due_at} (realtime={passage.is_realtime})"
            )


asyncio.run(main())

Errors are raised as typed exceptions (DeLijnConnectionError, DeLijnAuthError, DeLijnNotFoundError, DeLijnResponseError, all subclasses of DeLijnError) rather than logged and swallowed, so callers (e.g. a Home Assistant DataUpdateCoordinator) can react to failures.

You may pass in your own aiohttp.ClientSession; if you don't, one is created lazily and closed by client.close() (or on exiting async with).