Regex tester
Test a JavaScript pattern, read the groups, and preview a replacement.
Runs in browser
Use from your agent
Streamable HTTP at https://benchline.fabwaseem.com/mcp. No key. The tool name is test_regex.
mcp.jsonjson
1{
2 "mcpServers": {
3 "benchline": {
4 "url": "https://benchline.fabwaseem.com/mcp"
5 }
6 }
7}
tools/calljson
1{
2 "jsonrpc": "2.0",
3 "id": 1,
4 "method": "tools/call",
5 "params": {
6 "name": "test_regex",
7 "arguments": {
8 "pattern": "example",
9 "flags": "",
10 "text": "example"
11 }
12 }
13}
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How it works
Free JavaScript regex tester. Set flags, see every match and capture group, read a short explanation of the pattern, and preview a replacement. The match list is exact, which is what an agent needs when a model guesses.
- 01
Enter a pattern
Type the pattern without slashes. Turn on the flags you need.
- 02
Paste a sample
Matches are marked in the sample. Each row lists the index and the groups.
- 03
Preview a replacement
Leave the replacement empty to skip it. $1 and $<name> work as they do in JavaScript.