Utilities

Utilities are public helper hosts that complement RTCode.io and RTEdge.net. They show where a request comes from, query DNS and TLS, fetch other URLs for you, open any deployment, serve the official marks and favicons, list browser versions, and measure latency. Most of them are small RTCode deployments or edge workers on rt.ht. The status below is as of 2026-10-04. A host without a badge is available. An Experimental host or feature may change.

Hosts

HostWhat it doesStatusRead more
ip.rt.ht, ip.efn.krAnswers with your IP address and Cloudflare's view of your request, as JSON.Availableip.rt.ht and rq.rt.ht
rq.rt.htEchoes any request back as JSON.Availableip.rt.ht and rq.rt.ht
q.cf.rt.htQueries DNS, IP and ASN data, RDAP and WHOIS, TLDs and post-quantum TLS support in one call.Available. The CDN probes and the domain-availability types are Experimental.q.cf.rt.ht and qi.rt.ht
qi.rt.htThe QI console for q.cf.rt.ht.Availableq.cf.rt.ht and qi.rt.ht
whois.rt.ht, who.rt.ht, wi.rt.htA WHOIS front end for q.cf.rt.ht.Experimentalq.cf.rt.ht and qi.rt.ht
x.rt.htFetches a URL that you give as a base64 path. Deployments use it for twitter:image.The twitter:image role is available. Calling it yourself is Experimental.x.rt.ht, px.rt.ht and fp.cf.rt.ht
px.rt.ht, via.elefunc.netA proxy that rewrites request headers.Experimentalx.rt.ht, px.rt.ht and fp.cf.rt.ht
fp.cf.rt.htA CORS proxy that forwards only safe request headers, so it does not leak the visitor.Availablex.rt.ht, px.rt.ht and fp.cf.rt.ht
in.rt.htOpens any route through one gateway origin.Experimentalin.rt.ht and short links
rt.ht, go.rt.ht, get.rt.htShort links, and quick starts into the playground.Available. Remote Output codes, the CodePen hand-off and the other quick-start hosts are Experimental.in.rt.ht and short links
fv.rt.htText and emoji favicons as SVG, from a URL.Availablelogo.rt.ht and fv.rt.ht
browsers.page, api.browsers.pageThe latest browser versions, as a page and as JSON.Availablebrowsers.page
lt.rt.htMeasures latency from your browser to RTEdge.net and other platforms.Availablelt.rt.ht
push.rt.ht, wp.rt.htSend push notifications to yourself.ExperimentalWeb Push
u.rt.htThe Usage and Tail dashboards that ::u and ::t open. They need sign-in.ExperimentalUsage and tail logs
frozen.rt.htThe page that Freeze opens, to review a playground before it runs again.ExperimentalOutput windows
Every rt.ht hostAnswers /favicon.ico, /apple-touch-icon… and /robots.txt itself, before your deployment.AvailableReserved paths

Notes

Paths on helper hosts

Most helpers are ordinary RTCode deployments on rt.ht, so the platform's URL rules apply to them. A path with no trailing slash and no ., * or : is redirected with 307 to the same path with a slash, and the query is kept. rq.rt.ht/a/b becomes /a/b/, and fv.rt.ht/AB becomes /AB/. Use the /: form, such as fv.rt.ht/:AB, to reach a helper's worker without the redirect.

A path prefix is a route of its own. go.rt.ht/anything/ answers 404, "Code does not exist.", because the route go/anything has no deployment. Request routing explains routes.

Calling helpers from deployed pages

Code in the playground output can reach a helper where the same call from a deployed page fails. Helpers that send no CORS headers, such as x.rt.ht, or that do not answer every preflight, such as rq.rt.ht for PUT, PATCH and DELETE and px.rt.ht for custom headers and JSON bodies, work from the playground output but not from https://<name>.rt.ht. Test cross-origin calls from a deployed page. See Playground and edge differences.

Fetching from a worker

A worker on the rt.ht zone, whether a helper such as px.rt.ht or the edge worker of a deployment, gets a 522 when it fetches another host that a Workers route serves: every name.rt.ht deployment, rq.rt.ht and the rt.ht apex. Hosts that are Custom Domains of the zone, such as ip.rt.ht, in.rt.ht and q.cf.rt.ht, answer normally. The in.rt.ht gateway is the workaround for deployments: https://in.rt.ht/<route>/. via.elefunc.net reaches deployments directly.

Response headers

Every rt.ht response carries Server-Actual: RTEdge.net and a Server-Vendor header. Hosts that end in .rt.ht also get Strict-Transport-Security and Referrer-Policy: unsafe-url. See Response headers.

See also