A simple http record/replay proxy powered by http4k. It's so much faster than wiremock in my case

http4k-wiremock-alternative.kt

import org.http4k.client.JavaHttpClient
import org.http4k.core.Filter
import org.http4k.core.Request
import org.http4k.core.then
import org.http4k.filter.DebuggingFilters
import org.http4k.filter.RequestFilters
import org.http4k.filter.TrafficFilters
import org.http4k.server.SunHttp
import org.http4k.server.asServer
import org.http4k.traffic.ReadWriteCache

fun main() {
    val storage = ReadWriteCache.Disk("recordings")
    replaceHost("example.com")
        .then(RequestFilters.ProxyHost(RequestFilters.ProxyProtocolMode.Https))
        .then(TrafficFilters.ServeCachedFrom(storage))
        .then(DebuggingFilters.PrintRequestAndResponse())
        .then(TrafficFilters.RecordTo(storage))
        .then(JavaHttpClient())
        .asServer(SunHttp(9999))
        .start()
}

private fun replaceHost(host: String) = Filter { next ->
    { request: Request ->
        next(
            request.replaceHeader("Host", host)
        )
    }
}