Regex Tester
What This Tool Does
Regex Tester is built for deterministic developer and agent workflows.
Test regular expressions with real-time matching, group capture, and replace mode. Common patterns included.
Use How to Use for execution steps and FAQ for constraints, policies, and edge cases.
Last updated:
This tool is provided as-is for convenience. Output should be verified before use in any production or critical context.
Agent Invocation
Best Path For Builders
Dedicated API endpoint
Deterministic outputs, machine-safe contracts, and production-ready examples.
Dedicated API
https://aidevhub.io/api/regex-tester/ OpenAPI: https://aidevhub.io/api/openapi.yaml
Unified Runtime API
https://aidevhub.io/api/tools/run/?toolId=regex-tester&a=...
GET and POST are supported at /api/tools/run/ with identical validation and limits.
Limit: req / s, input max 512 KB.
REST API
Base URL
https://aidevhub.io/api/regex-tester/ 50 requests/day per IP. No authentication required. CORS enabled. OpenAPI spec
Endpoints
Example
curl "https://aidevhub.io/api/regex-tester/?pattern=%5Cd%2B&text=abc+123+def+456&flags=g"
Example Response
{
"valid": true,
"pattern": "\\d+",
"matches": [
{
"match": "123",
"index": 4
}
],
"match_count": 2
} How to Use Regex Tester
- 1
Enter your regex pattern
Type a regular expression in the pattern field (e.g., `^[a-z0-9._%+-]+@[a-z0-9.-]+\.[a-z]{2,}$` for email). Use flags (g, i, m) as needed.
- 2
Input test strings to match against
Paste or type multiple test strings in the input field. The tool will highlight all matches in real-time as you type.
- 3
View matches and capture groups
See all matches highlighted with their exact positions. If your pattern has capture groups (parentheses), see the captured values listed separately.
- 4
Check regex explanation
Read the auto-generated English explanation of what your regex does. This helps you debug patterns or learn regex syntax.
- 5
Test edge cases and iterate
Add more test strings to cover edge cases (empty strings, special chars, long text). Refine your pattern until all cases pass.