Short answer
These developer tools run entirely inside the web browser as ordinary JavaScript: JSON formatting, Base64 and URL encoding, JWT inspection, SHA hashing, UUID generation, Unix timestamp conversion and identifier case conversion. Nothing pasted in is transmitted, logged or stored, which matters more here than anywhere else on the site — the text a developer reaches for these tools with is routinely a token, a connection string or a production payload.
Turn a wall of JSON into something readable — or back into one line.
Turn text into Base64, with the alphabet your target expects.
Read what a Base64 string actually says.
Escape text so it survives being put in a URL.
Turn %E4%B8%AD%E6%96%87 back into something you can read.
See what is inside a token — without handing it to anyone.
Hash a string with SHA-256 and three of its relatives.
Random identifiers, generated on your own machine.
Turn 1717243800 into a date, and back again.
Rename a column of identifiers into the convention you actually need.
Every one of these is a small pure function over a string, which is why they finish in the time it takes to let go of the mouse. There is no engine to download, no worker to start and no request to wait for: the page you already loaded contains everything the conversion needs.
That also settles the question these tools usually raise. Pasting a signed token or a config file into a website means handing it to whoever runs that website, and the honest answer for most online formatters is that they receive it. Here the transform happens in the tab, so there is nothing to receive — you can disconnect from the network and every tool on this page still works.
No. Each tool is JavaScript running in your own tab, and there is no request in the code that carries your input. Open your browser's network panel and watch, or turn off your connection after the page loads — the tools keep working.
It is as safe as running the same code locally, because that is what is happening: the text never leaves your device, it is not written to storage, and it is gone when the tab closes. That said, the safest handling of a live production secret is always to not paste it into anything at all.
Yes. No account, no daily limit, no paid tier. Nothing here costs the site anything per use, because your device does the work.
No fixed one. These are string operations, so the practical ceiling is your tab's memory — a few megabytes of JSON is comfortable, and far more than anyone usually pastes into a text box.
Yes, once the page has loaded. Nothing here fetches anything, so an offline tab behaves exactly like an online one.
