Python Developer for E-Commerce Alert Program

We are looking for an experienced Python developer to build a program that sends alerts whenever new items are listed on the following five platforms:
① jp.mercari.com
② https://m.bunjang.co.kr/
③ https://paypayfleamarket.yahoo.co.jp/
④ https://fril.jp/?srsltid=AfmBOooWOImOZjvuSUKhg2sfCCztIG0eaSAYFmLCSyn1DXAbdT4kgsAU
⑤ https://auctions.yahoo.co.jp/

The program must be able to retrieve the latest product information within 1 second to ensure real-time updates. This has already been achieved by someone in China, but since I am a layman, I can only offer some ideas. For example, to achieve such performance, I suspect they must have found some kind of vulnerability or fundamental method—because the data shown when an item is listed on mercari.jp is, strictly speaking, second-hand information. What they capture is purely first-hand data that has not yet been made public.

Therefore, the ideal candidate should have experience with APIs and web scraping. If you are proficient in Python and passionate about building efficient systems, we sincerely invite you to apply.