Most "free online dev tools" quietly POST everything you paste to a server. For API payloads, tokens, or customer data, that's a bad default. A cleaner pattern: tools that do all the work client-side .
Source: [Dev.to](https://dev.to/aipredictions_dev/dev-tools-that-run-100-in-your-browser-your-data-never-leaves-the-page-2m22)