What are bitcoin Pool APIs?

[Bitcoin]

What are bitcoin Pool APIs?

I contacted a website and asked them where they get their data for crypto like Bitcoin, as I am trying to find the place for the most up to date and reliable data on Bitcoin and other crypto. They had sent me an email back saying they get their data from block explorers and pool apis. Block explorers were pretty self explanatory and easy to find and pull data from. But I wasn't 100% confident in my idea of what a Pool API was. Is it an API that is connected to a specific mining pool that gives you real time data? How do I set it up and where does the data get sent to? Or am I completely misunderstanding what it is?

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