Why this site exists
Anyone who runs a website, manages a server, or just fixes their home network ends up needing the same handful of answers over and over: What is my public IP address? Is this DNS record propagating? When does that certificate expire? Is the port actually open? Those questions are simple, but the tools answering them are often buried under pop-ups, sign-up walls, expired trials, and pages so heavy with advertising that the tool itself is the last thing to load. NetTools exists to be the opposite: a bookmark you can open, use, and close in under a minute, with the result explained in plain language rather than dumped as raw output you have to interpret yourself.
What you can do here
The site brings together two families of tools. The first is network diagnostics: a public IP lookup, a DNS record lookup, an SSL/TLS certificate checker, a single-port reachability checker, an internet speed test, and an IPv4 subnet calculator for planning and verifying network ranges. The second is everyday developer utilities that work on data rather than the network: a JSON formatter and validator, a Base64 encoder and decoder with proper UTF-8 handling, a Unix timestamp converter, a user agent viewer that shows what your browser tells every website, and a password generator that creates strong random passwords without sending them anywhere. Each tool page pairs the working tool with an explanation of the underlying concept — what the result means, how it is produced, and what to check when it is not what you expected — because a number without context rarely solves the problem you came with.
Our principles
Fast. Pages are hand-written, static, and light. Most tools finish in a single request or run entirely on your device, and nothing here waits on a framework, a tracker, or a consent banner before it works.
No accounts. There is nothing to sign up for and nothing to log into. Tools do not ask for your email address, and results are not saved to a profile, because a diagnostics tool simply does not need one.
Transparency. Wherever a result depends on a method, we say what the method is: which resolver answered a DNS query, what a port check can and cannot prove, why user agent parsing is approximate. Where a tool runs locally in your browser, we say so — and you can verify it by disconnecting and using it offline. Where a check must run from our server, we say that too.
Privacy by design. Local tools process data that never leaves your device. Server-assisted checks handle your query transiently, to produce the answer and nothing else. The full details are in our Privacy Policy.
Responsible diagnostics. These tools are built for checking systems you own or are authorised to test. Checks are deliberately narrow — one port, one host, one certificate at a time — and rate-limited, so NetTools cannot be turned into a scanner. Our Terms of Use spell this out.
How the site is operated
NetTools is run as a small, deliberately simple operation. The pages are static files served over HTTPS. A lightweight backend performs only the checks a browser cannot do itself — looking up your connecting IP address, opening a TLS connection to inspect a certificate, testing a single TCP port, and moving test data for the speed test — and it is rate-limited per visitor to keep it responsive and to prevent abuse. DNS lookups are answered through a public DNS-over-HTTPS resolver rather than our own infrastructure. There is no database of user queries behind any of it.
Accuracy and limits
Diagnostics show the network as seen from a particular vantage point — ours, or your browser's — at a particular moment. A port that is closed from our server may be open from inside your network; DNS answers differ by resolver and cache; a speed test measures the path between you and our endpoint, not your connection's theoretical maximum. We present results honestly, including their caveats, but they are a starting point for troubleshooting, not a verdict. Always confirm an important finding with a second method before acting on it.
Roadmap
The toolkit grows slowly and deliberately: new tools are added when they fit the same mould — instant, explained, and respectful of the visitor. Ideas under consideration include more DNS and mail-record diagnostics and additional local-only developer utilities. Just as important is what will not change: no accounts, no paywalled basics, and no dark patterns. If a tool here is wrong, broken, or missing something you need, the contact page explains how to reach us and what information makes a bug report easy to act on.