Coding and developer tools

Free Regex Tester.

Match results from an appropriate deterministic regex engine.

Prepare a reproducible regex test set and inspect both matches and failures before using the pattern in a workflow.

Chrome extension + account required.
25 free automation tasks/month across tools. Browser-provider limits apply.

WHAT TO HAVE READY

Pattern, flavor and sample strings.

YOUR STARTING POINT

A task you can make yours.

Copy it here. Paste it into WebAct when you are ready.

This page prepares your prompt. The task runs in WebAct.

01

Make the task yours.

Review the prompt above. Add your goal and any requirements that matter.

02

Bring it to WebAct.

Open WebAct, paste the task and provide the data and rules. Review any proposed calculation or code action before approving it, then check a known example.

03

Check the useful part.

Check formulas, code and calculations against known inputs in the appropriate runtime. Review actions before execution and keep the original data available.

A PRACTICAL GUIDE

How to use the Regex Tester.

Testing requires an actual compatible regex engine. Report the pattern, flags and sample strings so the result can be reproduced.

Make the workflow fit your task.

Run the supplied pattern and flags against explicit strings in a compatible regex engine. Record match status and, where relevant, captures or positions, keeping the exact test inputs available for reproduction.

What you provide
Pattern, flavor and sample strings.
What you get
Match results from an appropriate deterministic regex engine.

See the input and the result.

Illustrative input and output · a teaching example, not a live WebAct run

Example input

JavaScript expression /^cat$/ with no flags. Test cat, Cat, cats and a string containing cat followed by a newline.

Completed example

cat → true
Cat → false
cats → false
cat followed by a newline → false
Reproduce with: samples.map(value => /^cat$/.test(value))
Download this example

Load this input into the prompt, then copy it to WebAct to try the task. Your result may differ from the illustration.

Decisions and troubleshooting.

Can a prose explanation substitute for running regex tests?

It can describe expected behavior, but a test result requires actual evaluation in the stated engine. Keep predictions and executed results distinct.

Why do repeated tests behave differently with the same JavaScript pattern?

Inspect stateful flags and lastIndex handling, especially with global or sticky expressions. Use a deliberate reset or fresh instance for independent tests.

Reference for this workflow.

Try it with your own source.

Replace the example with your material in the task prompt. Keep the requirements you need, then copy the task into WebAct.

Customize and copy the task ↑
BEFORE YOU BEGIN

Using WebAct.

The prompt and example are available here. Run your task in the WebAct Chrome extension.

Is this tool free?

You can copy and edit the prompt here for free. To use it with WebAct, install the Chrome extension, create and verify your account, and connect an available browser ChatGPT session. The Free plan includes 25 user-started automation tasks per calendar month, shared across tools. Ordinary browser Chat is separate; provider limits apply.

Learn about shared context in our privacy policy and choosing Chat or Task.

FROM A PROMPT TO YOUR OWN WORK

Bring the task to your page.

Install WebAct, add your source material and make the result yours.

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