🔮Regex Tester
Test a regular expression against text and see every match: the matched substring, its index, and all capture groups. Deterministic — the same pattern and text always produce the same result, unlike LLM-simulated regex matching.
Worked examples
Extract emails
GET /api/v1/dev/regex-tester?pattern=%5B%5Cw.%2B-%5D%2B%40%5B%5Cw-%5D%2B%5C.%5B%5Cw.%5D%2B&flags=g&text=Contact%20jane%40acme.io%20or%20bob%40test.org%20today
Result: 2 matches
Capture groups
GET /api/v1/dev/regex-tester?pattern=(%5Cd%7B4%7D)-(%5Cd%7B2%7D)-(%5Cd%7B2%7D)&flags=g&text=Due%202026-01-15%2C%20shipped%202026-02-20
Result: 2 matches
Find hashtags
GET /api/v1/dev/regex-tester?pattern=%23%5Cw%2B&flags=g&text=Loving%20%23base%20and%20%23x402%20today!
Result: 2 matches
Machine API (x402)
$0.002 / callThis tool is also a JSON API for AI agents. Requests without payment receive 402 Payment Required plus instructions; agents pay USDC on Base via the x402 protocol — no accounts, no API keys.
GET /api/v1/dev/regex-tester?pattern=%5B%5Cw.%2B-%5D%2B%40%5B%5Cw-%5D%2B%5C.%5B%5Cw.%5D%2B&flags=g&text=Contact%20jane%40acme.io%20or%20bob%40test.org%20today HTTP/1.1
Host: localhost:3000
→ 402 (payment required, instructions in headers)
→ 200 (after X-PAYMENT header; JSON body below)
{
"tool": "dev/regex-tester",
"input": {"pattern":"[\\w.+-]+@[\\w-]+\\.[\\w.]+","flags":"g","text":"Contact jane@acme.io or bob@test.org today"},
"result": { "value": 2, "answer": "2 matches" }
}Agent docs: /llms.txt · OpenAPI spec · integration guide
About this tool
Test a regular expression against real text and see every match with its position and capture groups — the fastest way to debug a pattern before shipping it, and a building block for extraction pipelines.
Frequently asked questions
Which regex flavor is used?
JavaScript RegExp (ECMAScript). Most patterns are portable, but lookbehind and named groups use the JS syntax.