Node – What is the fastest WebSocket Bitcoin provider to access mempool data?

mempool.space has API-WebSocket.

You can get data like this:

• blocks: Last 15 blocks information, specific blocks can be assigned to Obatian itself and before 14 blocks data.
• mempool-blocks
• live-2h-chart
• stats

It’s not the best, but it works. It depends on what you want, but API-Rest is much better and provides more data.