Everything your browser and connection reveal — public IP address, user agent, timezone, screen resolution, and more. Updates live as you visit.
Your public IP address, browser, user agent, screen, and connection info are auto-detected and shown below. The IP comes from your last request to env.dev (server-side via the /ip endpoint); everything else is read locally from your browser via the standard Navigator and Screen APIs. Nothing is stored. If you'd rather check from the terminal, the curl shortcuts further down (curl env.dev/ip, /user-agent, /headers, /timestamp, /uuid) return the same data as plain text.
Use these from any terminal or script. All endpoints return plain text by default, JSON with Accept: application/json.
The IP shown above is the address env.dev's server saw on your last request — your public IP as observed from the internet. It can be IPv4 (e.g., 203.0.113.42) or IPv6 (e.g., 2001:db8::1) depending on your network. Private IPs (10.x, 192.168.x, 172.16-31.x) only exist inside your home or office LAN; the public one is what every site you visit sees.
The User-Agent string is a header your browser sends with every HTTP request. It identifies the browser, version, rendering engine, and OS — for example "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 ... Chrome/...". Sites use it for feature detection, analytics, and (sometimes) to send different markup to different browsers. Modern browsers also expose User-Agent Client Hints, which split the same info into structured headers like Sec-CH-UA.
Common reasons: (1) you're on a VPN or proxy that exits from a different IP, (2) your ISP uses CGNAT and you share a public IPv4 with many other users, (3) the other site is reading your IPv6 while env.dev is reading your IPv4 (or vice versa) on a dual-stack connection, or (4) you switched networks between visits. The IP env.dev shows is what Cloudflare's edge saw on the request to /ip.
Approximate location (usually city or region, sometimes only country), your ISP, and whether the connection is residential, mobile, datacenter, or VPN. It does not reveal your name, exact address, or browsing history. The country shown here comes from Cloudflare's `cf-ipcountry` header, which is GeoIP-based and accurate to country level for almost all consumer connections.
No. Everything below is rendered live from your current request and your browser's Navigator/Screen APIs. env.dev does not log per-visit IPs or user-agent strings. See /privacy for the full posture.
env.dev exposes plain-text endpoints you can curl directly: `curl env.dev/ip` for your public IP, `curl env.dev/user-agent` for your User-Agent, `curl env.dev/headers` for every request header as JSON, plus `/timestamp` and `/uuid`. Add `Accept: application/json` to /ip for `{"ip": "...", "country": "..."}`.
Screen resolution is the physical pixel dimensions of your display (e.g., 2560×1440). Viewport is the inner size of the browser window. Pixel ratio (DPR) is how many physical pixels map to one CSS pixel — Retina/HiDPI screens have DPR 2 or 3, so a 1440-CSS-pixel-wide layout actually uses 2880 or 4320 physical pixels. Designers care about DPR when shipping `srcset` images.
Read from `Intl.DateTimeFormat().resolvedOptions().timeZone`, which returns an IANA name like `Europe/Stockholm` or `America/Los_Angeles`. The UTC offset is computed live and reflects the current rule (DST or standard). Use the IANA name when storing user preferences — offsets shift twice a year for most regions.