Have you seen testserver.host? As part of building HTTP Toolkit I often need a remote servers for testing edge cases, so I've built one! Now fairly mature & stable. It's httpbin.org plus badssl.com plus lots of extras. testserver.host

Extras you say? * More endpoints, like /echo (echoes back raw HTTP), /encoding/zstd, and /error/reset * Websocket support * Faster & more reliable than either * Combining HTTP & TLS tests (give me an expired cert, then a 404 response) * Chainable endpoints, for both HTTP & TLS