Check a pattern
Enter a regex pattern, flags, and sample text to see matches.
Input
\btool\b with flag g
Output
Match count and matched text
Developer And Data Tools
Regex Tester
Test regular expressions against sample text locally in your browser.
Waiting
Runs in your browser. Files do not leave your device.
Input
Regex Tester. Paste text, run the tool locally, and copy the result.
Guide
How to use Regex Tester
Step-by-step
- Choose or enter regex, text in the workbench.
- Run the validation tool locally in your browser.
- Review the matches result, then copy or download it if the workbench offers that action.
- Use the related tools on this page for cleanup, validation, conversion, or the next step in the workflow.
Questions
Is Regex Tester free to use?
Yes. The public tool is free to use in your browser.
Are my files uploaded?
No. This tool runs locally in your browser, so selected files or pasted input are not uploaded to Convurter.
What should I check before using the matches result?
Regex behavior follows the browser JavaScript engine. Review the final output before using it in production work.
What can I do after this?
Good next steps include Text Diff, JSON Validator, and URL Parser.
Workflow fit
Use Regex Tester in the right place
If you are unsure, start from the data chooser and pick by shape: validate, convert, infer schema, export, decode, or clean.
Best for
- Developer and data cleanup where validation, formatting, schema inference, export, or local transformation is more useful than a static explanation.
- Preparing JSON, CSV, XML, YAML, TOML, NDJSON, URLs, hashes, certificates, or web text for another tool or system.
- A focused validate task where the expected output is matches.
Before you start
- This tool runs in the browser, so keep the tab open until the result is created and downloaded or copied.
- Validate syntax before conversion so malformed input does not become a confusing output problem.
- Remove secrets, credentials, production tokens, private customer data, and unnecessary identifiers before using any shared browser session.
- Know the target system requirements: delimiter, encoding, columns, date format, schema, or workbook expectations.
- Validate before converting or exporting so syntax problems stay visible at the earliest step.
Quality checks
- Review the output before sharing, publishing, submitting, or using it as a final artifact.
- Review row counts, keys, columns, nesting, encoding, and empty values after conversion.
- Use schema inference or validation before handing structured data to another workflow.
- For hashes and decoders, remember that readable output is not proof of trust or authenticity.
- Copy or download the result only after confirming the displayed output matches the task you intended.
Common mistakes
- Exporting to XLSX or CSV before flattening the data shape can hide nested values or create ambiguous columns.
- Treating JWT, certificate, or CSR decoding as verification. Decoding is not the same as validating trust.
- Assuming format conversion preserves comments, ordering expectations, or every data type nuance.
- Closing the tab before downloading or copying a browser-generated result.
- Treating a valid file as a useful file. Valid syntax can still contain wrong fields, units, rows, or assumptions.
Continue the workflow
Use these when the current result is only one step in a longer task.
Verify or clean up
Use these when the output needs checking, cleanup, comparison, compression, or a final share-ready pass.