https://jsonip.com serves something north of 10 million requests a day last time I checked. It's a free service I've run for years. I'm open to suggestions.
platform.launchrock.com/v1/getLaunchedSiteInfo:1 POST https://platform.launchrock.com/v1/getLaunchedSiteInfo net::ERR_INSECURE_RESPONSE
platform.launchrock.com/v1/getClientIP:1 POST https://platform.launchrock.com/v1/getClientIP net::ERR_INSECURE_RESPONSE
Which makes sense, since the certificate for https://platform.launchrock.com has expired, if I disable HTTPS Everywhere, the site loads just fine.