If you issue a 429, the client knows it needs to wait and retry, and you've pushed the backpressure all the way past the demarcation line of your own infrastructure.
maybe that doesn't help with ipv6, though. you'd run out of memory if you tried to keep track of every /128, and different ISPs hand out different blocks to customers (some give out a /64, maybe some give each customer their own /72, etc).
> The idea is that an OPTIONS request which doesn't take much resources at all could be treated with a different weight than a POST which costs the server time to process.
I'm curious, what frameworks/libraries/whatever have you seen that use HTTP OPTIONS ?
Every CORS pre-flight request uses the OPTIONS method. It is also used to advertise which methods are available on a route.
https://stackoverflow.com/questions/8685678/cors-how-do-pref...
Neat, thanks :) didn't know that