ToolBento guide
How to test a regex pattern online
Check a regular expression against sample text, review each match, and catch pattern mistakes before using it in code, redirects, filters, or cleanup work.
Recommended tool
Open the matching ToolBento utility →Start with a small real sample
A regular expression is easier to trust when you test it against text that looks like the data you actually expect. Copy a few representative lines into the tester: an email list, log snippet, product codes, URLs, support messages, or the messy text you want to clean up. Include at least one example that should match and one example that should not.
What to enter in ToolBento
Open ToolBento's Regex Tester and use two plain-language inputs. Test text is the block of text you want to search. Regex pattern is the expression itself, such as invoice-[0-9]+, https?://[^\s]+, or [A-Z]{2}[0-9]{4}. Enter only the pattern body, not surrounding slash delimiters.
Press Test to list the matches
After the sample text and pattern are ready, press Test. The tool runs the pattern with global and case-insensitive matching and lists each match on its own numbered line. If nothing matches, the output says No matches, which is a useful signal to simplify the pattern or check the sample text.
Use matched examples to refine the pattern
Read the numbered matches before copying the regex anywhere important. If the result grabs too much text, make the pattern more specific. If it misses valid examples, loosen the character class or length rule. A quick pass with three or four samples often catches mistakes that would be harder to debug inside application code.
Remember the tester uses JavaScript regex rules
The tester creates a JavaScript regular expression, so use syntax supported by the browser. Features can differ from regex engines in databases, command-line tools, and programming languages. If you are pasting the pattern into another environment, confirm flags, escaping, Unicode behavior, and lookbehind support in that environment too.
Be careful with copied delimiters and flags
Many examples online are written like /pattern/g or /pattern/i. In this tester, put pattern in the Regex pattern field without the outer slashes. The tool already applies global and case-insensitive matching. If your final code needs exact capitalization, test that separately in the destination system before shipping.
Common regex testing mistakes
Do not test only the happy path. Add punctuation, blank lines, similar-looking values, and malformed examples so the pattern fails where it should. Also avoid pasting passwords, private tokens, or sensitive customer records into any public page. Use realistic dummy data when a pattern can be tested without the real content.