Developer Tools

Developer tools are the small utilities that sit between the work you meant to do and the work you actually have to do. You have a JSON payload from an API that arrived as one unreadable line. A token from an Authorization header and no idea why the request is being rejected. A timestamp in a log that could be seconds or milliseconds. None of these is hard, and none of them is what you sat down to build — so what matters is getting the answer in five seconds and getting back to work.

Every tool in this category runs entirely inside your browser, and for developer work that is more than a nicety. The things you paste into these tools are exactly the things that should not be sent to a stranger's server: production API responses containing customer records, JSON Web Tokens that are live credentials, signed URLs, internal hostnames, configuration values. Most online developer tools upload your input to a backend to process it, which means using them on real data quietly hands a copy to someone else. Here the processing happens on your own machine using standard browser APIs, so nothing is transmitted — you can confirm that yourself by opening your network panel while you use one.

That constraint also makes these tools faster and more honest. There is no upload to wait for, no rate limit, no size cap imposed by someone else's hosting bill, and no account. It also means we tell you plainly what a tool cannot do: the JWT decoder reads a token's claims but does not verify its signature, because verification needs the signing key and any browser tool claiming otherwise would be misleading you.

Start with the JSON Formatter if you are staring at an unreadable API response — it reports the exact line and column where parsing failed, which is usually within a character of the real mistake. Reach for the JWT Decoder when a token is being rejected and you need to see its expiry. The Unix Timestamp Converter settles the seconds-versus-milliseconds question that causes more date bugs than anything else. Base64 and the URL Encoder handle the two encodings that data passes through on its way into headers and query strings. For generating rather than inspecting, the UUID Generator and Hash Generator both draw on your browser's cryptographic primitives rather than improvising.