Developer
Regex Tester
Test a regular expression against sample text and see every match, in your browser.
Focused calculator
Calculate Regex Tester
3 matches: 123, 456, 7
When to use this tool
Use the Regex Tester for quick, focused data cleanup directly on the page before copying the output into code, documentation, spreadsheets or another tool.
- Debugging, API work, import/export cleanup and code-adjacent formatting tasks.
- Transforming text or data quickly without sending browser-only tools to a server.
- Copying a deterministic output into scripts, documentation or another tool in the same workflow.
Accuracy, privacy and assumptions
- This is a browser-only tool: input is processed by JavaScript on the page and is not uploaded to Convematik.
- For copied tokens, session data or private payloads, still review the output carefully before sharing it anywhere else.
Common mistakes to avoid
Most wrong answers from a Regex Tester come from unit direction, rounding too early, or copying a result without its original context.
- Do not paste secrets into tools that expose API endpoints unless the page clearly states the work is browser-only.
- Do not import generated output into production until you validate structure and escaping.
- When a format has multiple dialects, test the output with the destination tool before scaling the workflow.
- Do not paste the generated output into another service until you have removed anything private or account-specific.
Copy-ready result format
Regex Tester output: 3 matches: 123, 456, 7 (Pattern \d+ on the sample).
- Keep the original input available until the destination accepts the transformed output.
- Copy validation errors along with the input when debugging a failed import.
- Use browser-only pages for sensitive copied text or account-like payloads.
Best workflow for Regex Tester
- Paste or type the input into the tool above.
- Choose the target mode or format when the tool offers one.
- Review validation errors and copy the output only after it matches the expected structure.
- For sensitive data, prefer browser-only tools and avoid API-enabled endpoints.
Next steps after this result
After the immediate calculation, choose the next tool based on what you plan to do with the value.
- Validate output with the destination parser.
- Automate through the API only after a single-page test passes.
- Keep private values out of API-enabled tools.
Formula
How it works: Your pattern is compiled with the given flags (g, i, m, s, u, y) and run against the test string using the browser's JavaScript regex engine. Matches and capture groups are listed.
Common examples
| Input | Result |
|---|---|
| \d+ on 'a1 b22' | 1, 22 |
| flag i | case-insensitive |
| flag g | all matches |
JSON API example
This tool runs entirely in your browser. Your input is never sent to a server, so there is no API endpoint for it.
Common questions
What does the Regex Tester do?
Test a regular expression against sample text and see every match, in your browser.
Does the Regex Tester send my data to a server?
Everything in the Regex Tester runs locally in your browser using JavaScript. Your input is never uploaded, logged or stored on a server.
When should I use the Regex Tester instead of a spreadsheet or script?
Use the Regex Tester for quick validation, formatting, decoding or cleanup when you need a deterministic output before copying the result into code, docs, an API request or a spreadsheet.
Is the Regex Tester free to use?
Yes. The Regex Tester is free and does not require an account.