What Is My IP Address? — Find Your Public IPv4 and IPv6 Instantly

Your public IP address is the unique identifier the internet assigns to your
network. Websites, APIs, and remote servers see this address when you connect.
Use this tool to check your current IPv4 and IPv6 addresses in real time — no
configuration needed, the detection runs automatically as soon as the page loads.

This tool detects your current public IPv4 and IPv6 addresses using public IP echo endpoints. Useful for verifying which IP addresses external servers see when you connect to them, checking VPN or proxy configurations, or diagnosing IPv4/IPv6 dual-stack connectivity.

How IP Address Detection Works

Every device connected to the internet communicates using the Internet Protocol.
When you visit a website, your device initiates a TCP connection to the server.
Embedded within that connection is the source IP address — the unique numerical
label your internet service provider assigned to your router or device at the
moment of connection. This is the address the wider internet sees, regardless of
any local network addresses your devices use internally.

An IP address lookup tool works by reading this source address from the incoming
request. When your browser loads the page, it sends an HTTP request through your
router, across your ISP’s infrastructure, through any intermediate networks, and
ultimately to the web server. The server extracts your address from the network
layer of the connection and returns it back to you in the response. Behind a
reverse proxy or a content delivery network such as Cloudflare, the edge node
forwards your real address in an HTTP header like CF-Connecting-IP so the
origin server knows the actual client rather than the proxy’s own address.

This mechanism is the same one every website, API, and online service uses to
identify where traffic originates. It is fundamental to geolocation, access
control lists, rate limiting, DDoS mitigation, and audit logging. Without it,
the internet would have no way to route responses back to the correct
destination.

Both major versions of the Internet Protocol are supported:

• IPv4 — the fourth version of the protocol, deployed in 1983. It uses
  32-bit addresses typically written in dotted-decimal notation (four octets
  separated by periods, such as 192.0.2.1). The 32-bit address space allows
  roughly 4.3 billion unique addresses. Network Address Translation (NAT)
  extends this by allowing many devices behind a single public IPv4 address to
  share connectivity. Despite its age, IPv4 still carries the majority of
  global internet traffic today.
• IPv6 — the successor protocol standardized in 1998 to address IPv4
  exhaustion. It uses 128-bit addresses written as eight groups of four
  hexadecimal digits separated by colons (such as 2001:db8::1). With
  340 undecillion possible addresses, IPv6 eliminates the need for NAT and
  enables true end-to-end connectivity. Adoption has accelerated as regional
  internet registries have exhausted their IPv4 allocations, and all major
  operating systems, browsers, and cloud providers now support IPv6 natively.

If only one address family is detected, the other is reported as unavailable.
This is expected — most residential connections operate in dual-stack or
IPv4-only mode depending on the ISP’s deployment.

Results are cached in your browser using a short-lived local storage entry to
avoid unnecessary network requests when the page is reloaded. The cache does
not persist across browser sessions or devices.

Why You’d Want to Look Up Your IP

Knowing your public address is useful in many everyday situations:

• Remote access and firewall rules — when you whitelist an IP address in a
  security group, database firewall, or server ACL, you need your current
  public address. Check it here, copy it, and paste it into your cloud console
  or router configuration.
• VPN and proxy verification — after connecting to a VPN or proxy service,
  reload this page to confirm your traffic is now egressing from the expected
  geographic location and IP range.
• Troubleshooting connectivity — if a remote service reports that your
  connection is being blocked or rate-limited, verify which IP address your
  traffic is coming from so you can provide it to the support team.
• DNS and CDN debugging — when testing DNS changes or Cloudflare proxy
  settings, confirm whether your requests are hitting the origin server directly
  or passing through the CDN by checking the address the origin sees.
• Dual-stack network testing — confirm that both IPv4 and IPv6 connectivity
  are functional from your current location. If IPv6 shows as unavailable while
  you know your ISP supports it, there may be a local router or operating system
  configuration issue.

API Access for Automation

You can query your IP address programmatically using our public REST API. Always
use HTTPS — Cloudflare enforces it:

Linux / macOS (curl):

curl -s "https://api.crtmgr.com/api/v1/ip" | python3 -m json.tool

Windows (PowerShell):

Invoke-RestMethod -Uri "https://api.crtmgr.com/api/v1/ip" | ConvertTo-Json

Windows (cmd):

curl -s "https://api.crtmgr.com/api/v1/ip"

The response is a JSON object with ip (your public IPv4 address or empty),
ipv6 (your public IPv6 address or empty), and user_agent (your browser’s
User-Agent header). If an address family is not available, the corresponding
field is null.

Rate limits apply per calling IP: 1 request per second, 60 per minute, 1000 per
day. For most use cases this is more than sufficient. Avoid polling in tight
loops — the five-minute client-side cache handles repeated page loads without
touching the API.

Privacy

Your IP address is read from the incoming connection to provide the lookup
service. It is not logged to persistent storage. In-memory rate-limit counters
keyed by IP exist only to protect the API from abuse and are not retained across
service restarts.

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