What happens to what you paste
Every tool — formatting, validating, viewing, diffing, converting, Base64 and URL encoding — runs as JavaScript on the page. The text and files you paste or open are processed on your device and are not uploaded, logged or stored by FormatKit.
The one exception: “Explain & repair”
On the JSON Validator, if you click Explain & repair, the invalid snippet (up to 12,000 characters) and the validator’s error message are sent to our server and forwarded to an AI model through Vercel AI Gateway to generate an explanation. FormatKit does not store the snippet or the answer. The call only happens when you click the button — never automatically. Avoid sending secrets or personal data.
What is stored in your browser
Option choices such as indent width, “sort keys” or the URL encoding mode are saved in your browser’s localStorage under formatkit:prefs so they are the same next time. Your input is never saved.
Analytics
We use Ahrefs Web Analytics to count page views. It is cookieless and does not collect what you type into the tools. Hosting is provided by Vercel, which keeps standard server logs (such as IP address and requested URL) for security and operations.
No accounts
There are no sign-ups, logins or databases on FormatKit.