Hyperswitch is free to use for the first 10k transactions of the month. After that it costs $0.04 per transaction. It is a payment switch that comes pre integrated with major processors. So as a merchant your business relationship with processors like Stripe or Adyen remains the same (I'm affiliated with this product)

> who's running it.

Juspay is an Indian payment aggregator. They are quite big and are used by high profile brands: https://juspay.in/