Test a String with Regex
Check whether a string matches a regular expression. Runs entirely in your browser, so your data never leaves your device.
0 chars · 0 lines
Output
The result appears here as you type.
How to use Test a String with Regex
- 1. Paste the string to check. Enter the text you want to validate into the input pane, whether it is a single value like an email address or a longer block of text.
- 2. Enter the Regular expression. Type the pattern you want to test against into the Regular expression field, using standard JavaScript regex syntax without the surrounding slashes.
- 3. Set Ignore case and whole-string matching. Turn on Ignore case to match regardless of letter casing, and turn on Require the whole string to match to anchor the pattern to both ends instead of allowing a partial match anywhere inside.
- 4. Read the match result. The output reports whether the input matches the pattern under the chosen settings, giving you a clear yes or no answer for the exact input you supplied.
When to use Test a String with Regex
Test a String with Regex checks whether a given piece of text matches a regular expression, with options to ignore case or require a full match. Use it to verify a pattern works correctly before wiring it into validation code.
- Validating an email or phone pattern. You wrote a regex meant to validate email addresses or phone numbers and want to try it against several real and fake examples before adding it to a form's validation logic.
- Debugging a failing validation rule. A form field keeps rejecting input that looks correct, and testing the exact regex against the exact string reveals whether the pattern or the input is the problem.
- Checking whole-string versus partial matches. You are unsure whether your pattern is accidentally matching a substring instead of requiring the entire input to conform, and toggling whole-string matching clarifies the behavior.
- Confirming a naming convention. A team style guide requires branch names or file names to follow a specific pattern, and you want to quickly check whether a proposed name satisfies the rule.
Examples
Is it all digits?
Input
12345
Output
Match: yes
About the Test a String with Regex tool
Test a String with Regex does its work locally, right in the browser. Check whether a string matches a regular expression. There is no upload step, no queue and no account, and your data never travels over the network.
It belongs to the String Tools collection on EditSafely, a set of 159 small, focused String utilities that share the same instant, private workspace.
You can shape the output with 3 settings, including Regular expression, Ignore case and Require the whole string to match, and the result refreshes the moment you change one. A worked example further down the page shows exactly what the tool produces for a real input.
Running locally also makes the tool fast and dependable: results appear as you type or drop a file, there is no server outage that can take it down mid-task, and confidential data can be processed without a second thought.
Frequently asked questions
Does Test a String with Regex cost anything?
Yes, it is completely free. All 2,658 tools on EditSafely work without an account, a subscription or usage limits.
Is it safe to paste sensitive or confidential data?
No data leaves your device. The whole tool is JavaScript that runs inside your browser tab, so there is no upload, no server-side processing and no log of what you did. If you disconnect from the internet after the page loads, it keeps working.
How much text can I process at once?
There is no fixed limit. Because the work happens on your own device rather than on a shared server, the practical ceiling is your machine's memory, which comfortably handles inputs far larger than typical online tools allow.
Do I need to sign up or install anything?
Nothing to install and no account needed. Open the page in any up-to-date browser, including on a phone or tablet, and the tool is ready.
How do I use the result?
The output panel has a one-click copy button, and you can keep refining the input while you work; the result updates in place as you type.