Free tools
Free developer tools.
The tools you keep googling, in one place. No signup, no ads, and nothing uploaded: they all run in your browser tab. All 12 of them are live.
These are the tools most developers end up googling several times a week, rebuilt so you do not have to think about where the page came from. Every one runs entirely in your browser tab: there is no account, no upload step, and no request to a server when you press the button. That matters most for the JWT decoder, since a token is a credential, and pasting a live one into a site that posts it somewhere hands over whatever that token can reach.
They are grouped by what you are trying to do rather than by technology. Formatting and validation for when something will not parse, decoding for when you need to read an opaque string, time tools for epochs and cron schedules, matching for regular expressions and diffs, and conversion for moving between JSON, CSV and YAML.
Want them on your desktop?
Toolbelt puts the same tools in a native Mac app: no browser tab, works with no connection at all, reads from your clipboard and handles whole folders at once.