API · no key required
No key to request, no signup, no call quota. Hit the root path from a shell and you get plain text, /json gives the full report, and /api/whoami returns exactly the same fields. Everything is read by the edge node straight from your connection, without any third-party API, and nothing is stored server-side.
# just the IP (-L follows the forced-HTTPS 301)
$ curl -L ip.fs.kg
203.0.113.42
# the full report, pick the fields you need
$ curl -sL ip.fs.kg/json | jq '{ip,country,city,asn,org}'
{ "ip": "203.0.113.42", "country": "CN", "city": "Xiamen", "asn": 4134, "org": "Chinanet" }
# drop it into your shell prompt
$ PS1="$(curl -sL ip.fs.kg) $ "On Windows PowerShell, write curl.exe: curl in PowerShell is an alias for Invoke-WebRequest, which speaks plain http, hits the forced HTTPS redirect and returns 400 The plain HTTP request was sent to HTTPS port.
/
The root path. When a command-line client such as curl, wget or httpie asks for it, the answer is one line of plain-text IP with no HTML around it; a browser still gets the full interface. The split is decided by User-Agent and Accept, so neither side gets in the other's way.
203.0.113.42/json
The full report as application/json. Add ?pretty for two-space indentation when reading it by eye; without it you get one compact line, which suits piping. It exists because it is shorter to type than /api/whoami and does not live under /api/, which robots.txt disallows.
{
"ip": "203.0.113.42",
"type": "IPv4",
"asn": 4134,
"org": "Chinanet",
"city": "Xiamen",
"country": "CN",
"latitude": 24.4798,
"longitude": 118.0819,
"timezone": "Asia/Shanghai",
"colo": "HKG",
"tlsVersion": "TLSv1.3",
"edge": true
}/api/whoami
The same implementation and the same fields as /json. The path differs only because the homepage script consumes it and appends a timestamp to dodge caches. The two are interchangeable.
/api/contact
this site only
The relay behind the contact form. It only accepts same-origin requests from this site's own pages; third-party calls get a 403, so there is no public usage to document. It is listed here so the endpoint inventory is complete: the body is {name, email, message, page}, success returns {"ok":true}, and rate limiting returns 429.
| Field | Type | Notes |
|---|---|---|
| ip | string | Your public address |
| type | string | IPv4 or IPv6, decided by whether the address contains a colon |
| asn | number | Autonomous system number, e.g. 4134 |
| org | string | Network organisation name. At the edge isp comes from the same source and may be null |
| isp | string | ISP name, same value as org |
| city / region | string | City / region, may be null |
| country | string | Two-letter country code, e.g. CN |
| country_code | string | Identical to country, kept for older callers |
| continent | string | Continent code, e.g. AS |
| latitude / longitude | string | City-level approximation. May be a numeric string ("24.47979") — run it through parseFloat yourself |
| postal | string | Postal code |
| timezone | string | IANA zone name, e.g. Asia/Shanghai |
| isEu | boolean | Whether the address is inside the EU |
| colo | string | Three-letter code of the edge node that handled this request, e.g. HKG |
| tlsVersion | string | Negotiated TLS version, e.g. TLSv1.3 |
| tlsCipher | string | Negotiated cipher suite |
| httpProtocol | string | HTTPS or HTTP |
| acceptLanguage | string | First value of the Accept-Language request header |
| edge | boolean | Always true, marking that the data was read at the edge rather than from a third-party API |
| ts | number | Millisecond timestamp, different on every request, handy for busting intermediate caches |
Below is what this page actually got back from /api/whoami. A runnable example beats a pasted block of fake data — the values you see are your own, right now.
Requesting…