How to Use the Regex Tester

2. How to use the Regex Tester

Here is the whole process, step by step. It takes less than a minute from opening the tool to seeing your result.

1. 1Fill in the Pattern, Flags, Test string, Matches highlighted fields.
2. 2Your result appears on the page.

Your result updates as you type — there is nothing to press and nothing to wait for.

Everything runs in your browser — your files and text never leave your device.

3. Tips for best results

1. Your text never leaves your device — The tool runs entirely in your browser using JavaScript. Nothing is uploaded, so you can paste private documents without worry. That also means there is no account to create and no file to upload.
2. It works on your phone too — Open the tool in any modern browser on Android or iPhone. The layout adjusts to the screen and everything works the same way on a small screen as on a desktop.

Related tools

More developer tools you may like — all free, no signup.

• API Request Tester — Send GET, POST, PUT and DELETE requests with headers and body, and view the status, headers and response. · how-to guide
• JSON Formatter & Validator — Format, beautify, validate and minify JSON with clear error messages and line numbers. · how-to guide
• Base64 Encode / Decode — Encode text to Base64 or decode Base64 back to text, with full UTF-8 and URL-safe support. · how-to guide
• URL Encode / Decode — Percent-encode text for safe use in URLs and query strings, or decode encoded URLs. · how-to guide
• UUID Generator — Generate cryptographically secure random UUID v4 / GUID values in bulk. · how-to guide
• JWT Decoder — Decode a JSON Web Token to read its header, payload and expiry time. Nothing is sent to a server. · how-to guide