Regex Tester

Enter a regex pattern and test text to see all matches, captured groups, and their positions. Supports case-insensitive, multiline, dotall, and unicode flags. Great for validating patterns before using them in code.

Regex Pattern Required

Without delimiters (e.g. ^[a-z]+$)

Test Text Required

Advanced options

Flags Optional

i=case-insensitive, m=multiline, s=dotall, u=unicode

Global Match Optional

Find all matches, not just the first

Get an API key to automate this

Result

Code snippets

What this tool checks

All matches with positions and lengths
Captured groups and named groups
Case-insensitive, multiline, dotall, unicode flags
Global or first-match-only mode
Execution time measurement
ReDoS protection (backtracking limits)

Automate this with the API

Run this tool programmatically from your code. Get a free temporary API key with 20 requests/day — or register for 75 requests/day.

                    curl https://apixies.io/api/v1/test-regex?pattern=... \
  -H "X-API-Key: YOUR_API_KEY"
                

Get Temporary API Key View API Documentation →

Frequently asked questions

Do I need to include delimiters?

No. Enter just the pattern without / delimiters. The API adds them automatically. For example, enter ^[a-z]+$ instead of /^[a-z]+$/.

What flags are supported?

Four flags: i (case-insensitive), m (multiline, ^ and $ match line boundaries), s (dotall, . matches newlines), and u (unicode mode).

Is there protection against slow patterns?

Yes. The regex engine has a backtracking limit to prevent ReDoS (Regular Expression Denial of Service) attacks. Patterns that cause excessive backtracking return an error instead of hanging.

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