Paste an HTTP response and get Regular Expression Extractor fields for tokens, CSRF, and UUIDs. Browser-only analysis; nothing is uploaded. Max 1 MB.
JMeter Regex Extractor Builder
Section titled “JMeter Regex Extractor Builder”Paste a response body. The tool scans for likely dynamic values (tokens, CSRF fields, UUIDs, JWTs) and proposes Regular Expression Extractor settings you can copy into JMeter.
Browser-only. Your response body is analyzed in this tab and is never uploaded. Max paste size: 1 MB (1,048,576 bytes). Focus: Regular Expression Extractor only.
Candidates
Paste a body and click Find dynamic params. We suggest fields for the Regular Expression Extractor (variable, regex, template, match no.).
Selected-
Confidence-
Preview $1$-
Name of created variable
Template
Match No.
Regular Expression
Default Value
Output targets the Regular Expression Extractor post-processor. For pure JSON, prefer the JSON Extractor. Docs: Regular Expressions.
Privacy and limits
Section titled “Privacy and limits”| Rule | Detail |
|---|---|
| Where it runs | 100% in your browser (this page). |
| What is sent | Nothing: no upload, no server analysis. |
| Max body size | 1 MB (1,048,576 bytes). Larger pastes are rejected so the tab stays responsive. |
| Scope | Regular Expression Extractor only (not JSON Extractor / Boundary Extractor). |
Extractor field mapping
Section titled “Extractor field mapping”| JMeter field | This tool |
|---|---|
| Name of created variable | Suggested from key / type |
| Regular Expression | Generated pattern with one capture group |
| Template | $1$ |
| Match No. | 1 (first match) |
| Default Value | NOT_FOUND |
- Prefer JSON Extractor when the entire body is JSON; more stable than regex.
- Always verify with a Debug Sampler or View Results Tree; browser JS RegExp is close to Java but not identical.
- If nothing is found, paste a smaller fragment that still includes the token and its key.
Related reading
Section titled “Related reading”People Also Ask
How do JMeter regex extractor templates like $1$ work?
Parentheses in the regular expression create capture groups. The template field can reference those groups as $1$, $2$, and so on, or $0$ for the full match. Match No. selects which occurrence to use when the pattern matches multiple times.
Should I use regex or JSON Extractor in JMeter?
For JSON responses, prefer JSON Extractor or JMESPath when possible because they understand structure better than brittle regular expressions. Use regular expressions for HTML snippets, tokens in free text, or protocols without a dedicated extractor.
Does the Regex Extractor Builder upload my response body?
No. The builder runs entirely in your browser. The pasted response is analyzed locally and is not uploaded to any server. Maximum paste size is 1 MB so the page stays responsive.
How do I extract a CSRF or access token with JMeter Regular Expression Extractor?
Paste a sample response into the Regex Extractor Builder, pick the token candidate, then copy Name of created variable, Regular Expression, Template $1$, Match No. 1, and a Default Value such as NOT_FOUND into a Regular Expression Extractor under the sampler that returns that body.
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