What is the cheapest WHOIS API available?
And generally why is it so expensive? I mean yes it takes server resources to query data but we are in 2021 and domain industry has come a long way but still WHOIS API is not cheap.
That's because of the various registries and their limits on how many times one can query a whois.
That is what leads any whois tool to use multiple servers to provide you with a stable service and that leads to very high costs.