Given a company's careers page URL, detect whether it's backed by Greenhouse, Lever, or Ashby and extract the board slug usable with greenhouse.io/get_company_jobs, lever.co/get_company_jobs, or ashbyhq.com/get_company_jobs. Detection combines two signals: network requests fired by the page (Greenhouse/Lever client-side API calls, seen e.g. on discord.com/careers) and embedded links to the ATS's own hosted board (seen e.g. on notion.com/careers linking jobs.ashbyhq.com/notion). Many companies fully proxy their ATS server-side with no client-visible signal (e.g. careers.airbnb.com, retool.com/careers) - for those this returns platform: null, which is a legitimate outcome, not a failure. Point this at the company's own marketing careers page, not at a guessed ATS URL: several large companies (e.g. Airbnb, Coinbase) configure their native Greenhouse board (boards.greenhouse.io/<slug>) to redirect to their custom-branded career site, which then also yields platform: null.
