RegEx Tester
Test a Python regular expression against sample text and download a JSON match report.
This tool preserves normal PDF quality and structure for its core operation.
Options
Using RegEx Tester
Test a Python regular expression against sample text and download a JSON match report.
How to Use RegEx Tester (Step-by-Step)
Follow these quick steps to achieve optimal results in seconds.
Choose or Import Files
Input your parameters or text directly into the interactive workspace.
Configure & Preview
Customize available settings, page ranges, or compression levels with real-time feedback.
Immediate Download
Execute processing and download your finalized output instantly without countdowns or watermarks.
Workflow
Enter a pattern and sample, choose flags and process the request to inspect positions and captures.
Example to try
Try [0-9]+ against Order 123 to inspect the numeric match and its position.
Illustrative check using non-sensitive sample input; not a claim of a measured production result.
Limitations and review
This is server-side Python regex, not live JavaScript regex. Patterns have a one-second timeout and reports cap matches at 1,000.
Processing and privacy
Input files or text and selected options are sent to a server processing job. Review the upload limits and job expiry shown in the workspace. Expiry and scheduled physical cleanup are separate events.
Read our full privacy policy →Privacy Guaranteed
Isolated sandbox execution with automated 30-min file deletion.
No Quality Loss
Lossless vector preservation and crisp high-DPI rendering without watermarks.
Immediate Access
Instant downloads with zero registration, subscriptions, or forced waiting gates.
Technical Specifications & Input Settings
This tool accepts the text or settings entered in the workspace; a file is not required.
- Regular expression
- Required input; use the workspace controls.
- Sample text
- Required input; use the workspace controls.
- Flags
- none / i / m / s / im
Questions about RegEx Tester
Frequently asked technical and operational questions about regex tester.
Which regular expression engine does the RegEx Tester use?
It executes Python's standard re module engine on the server, supporting lookaheads, lookbehinds, named capture groups, and standard regex flags (i, m, s).
How does the tester handle runaway regex patterns and timeouts?
Processing is protected with a strict one-second execution timeout and match result caps to protect against catastrophic backtracking and CPU exhaustion.
Where does RegEx Tester process my test strings?
Pattern matching executes on our secure server sandbox with isolated memory limits, and entered test patterns and samples are never permanently logged.