Your text stays in your browser
The regex tester, builder, encoders, hash generator, diff checker, JWT decoder, JSON formatter, case converter and UUID generator all run as JavaScript on this page. What you paste into them is not sent to or stored on our servers.
The AI features
When you press Generate regex, Explain regex or Explain in depth with AI, the text you entered (up to 600 characters, plus up to 400 characters of example text) is sent to our server and forwarded through Vercel AI Gateway to the model provider (OpenAI) to produce the answer. RegexKit does not store these requests. Your IP address is held in memory for a few minutes only to enforce a rate limit. Don't submit secrets or personal data.
What's saved on your device
To save you retyping, this site keeps a few things in your browser's localStorage, under keys starting with rk:: the last pattern, flags and test text in the regex tester, patterns you chose to save, and your last 10 AI generator prompts. They never leave your device.
Analytics
We use Ahrefs Web Analytics to count page views. It is cookieless and does not collect personal data or build profiles across sites.
Share links
"Copy share link" puts your pattern and test text in the part of the URL after #. Browsers don't send that part to servers, but anyone you give the link to can read it.