The everyday utilities of software work, without leaving the browser or trusting a random site with your payloads: formatters and validators for JSON, XML, YAML and SQL; encoders for Base64 and URLs; a regex tester running the real JavaScript engine; and converters between the formats data actually travels in.
Everything here works offline once the page loads, and anything you paste — tokens, API responses, customer exports — is processed locally. The JSON Formatter, JWT Decoder and Unix Timestamp Converter are the ones developers keep pinned.