// TOOLS · RUN IN YOUR BROWSER

Network tools that keep your data on your machine

Every tool here does its work inside the page. A certificate you paste, a HAR file you open, the hardware address of the unknown device on your Airbnb's Wi-Fi: none of it is sent to a server, because there is no server behind these pages that could receive it.

IPV4 · IPV6 · CIDR

Subnet Calculator

Network, broadcast, host range and wildcard for any CIDR, IPv4 or IPv6. Turns an IP range into the CIDR blocks that cover it.

OUI · MA-L · MA-M · MA-S

MAC Vendor Lookup

Which company made the device behind a hardware address, from the IEEE registry. Spots randomised private addresses too.

X.509 · PKCS#10 · PEM · DER

Certificate & CSR Decoder

Subject, issuer, validity, key, SANs, key usage and fingerprints from a certificate or signing request. Parsed in your browser.

VPN · RESOLVER · PRIVACY

DNS Leak Test

Which DNS servers actually answer your lookups on this connection, who owns them, and whether your VPN or private DNS is really being used.

CLOUDFLARE · GOOGLE · QUAD9 · 8 RESOLVERS

DNS Benchmark

Times eight public resolvers from where you are, over DNS-over-HTTPS, and ranks them by median response.

TCP · UDP · WHAT IS PORT…

Port Lookup

What a port number is used for, which home devices open it, and whether it matters that it is reachable.

HTTP ARCHIVE

HAR Analyzer

Open a HAR file and see what a page really loaded: third parties, slowest requests, insecure cookies, servers that leak versions.

PUBLIC IP · FINGERPRINT

What Is My IP

Your public address and everything else your browser hands to every site you visit, without asking.

// REFERENCE

Unknown device on my Wi-Fi

Espressif, Tuya, AzureWave, Redpine, AMPAK, Murata, Hon Hai: who those names in your router are, what the gadget probably is, and whether it could be a camera.

What is that port

Every port that shows up on a home network, from 22 and 443 to 62078 and 32400: what listens there and what it means if the internet can reach it.

ON YOUR PHONE · 24 TOOLS

These pages cover what a browser is allowed to do. The app does the rest from your pocket: scan the Wi-Fi you are on, find every device, check what is exposed, and tell you what it could not see. Get RECON for iPhone — one-time purchase, no account, nothing leaves the device.

Why browser-side

Most online network tools are a form that posts your input to someone else's server, which then keeps a log of it. That is a poor deal for a certificate signing request, a HAR file full of session cookies, or the hardware addresses of everything in your house. These tools run as code in your browser instead. Open the network inspector while you use one: there is nothing to see.