Transport for London API
Transport for London (tfl.gov.uk) has 2 public methods: get line status and plan a London journey. Each costs 1 credit per completed run (1¢ with pay as you go); failed runs are free.
Unofficial. Not affiliated with or endorsed by Transport for London.
Methods
2Gets the current or future-day service status for London Tube, Elizabeth line, DLR, Overground, tram or a named bus route. Multiple notices on one line are combined into the most disruptive status.
Returns line name, type, status, reason, valid from/to, line id, severity number
Readtfl.gov.uk/get_line_statusPlans a London public transport journey between two places, stations, addresses or postcodes with the TfL Journey Planner, leaving or arriving at a given time. Returns journey options in TfL order with leg directions and an adult pay-as-you-go fare when available.
Returns departure and arrival times, total time, adult pay-as-you-go fare, legs with mode, line, stops, time and instruction, TfL results link
Readtfl.gov.uk/plan_journey