# Regex text extractor — matches to CSV, no upload

> Run a regex against .txt or .log files and turn capture groups into CSV columns, streaming large files in a worker. Runs in your browser with no upload.

Run a regular expression against text or log files and turn each capture group into a CSV column, streaming files up to hundreds of megabytes in a worker. Nothing is uploaded.

Logs and text dumps hide structured data behind a pattern. A regex with capture groups pulls that structure out — timestamps, IDs, error codes — into a clean table you can analyse, all without shipping sensitive logs to a service.

Streaming in a worker keeps big files responsive. To interactively browse a log instead, use the Log viewer; to then query the extracted rows, use SQL.

## How to

1. **Add a text/log file.** Drop a .txt or .log file to search.
2. **Write a regex.** Enter a pattern with capture groups for the fields you want.
3. **Extract.** Matches stream into rows, one column per capture group.
4. **Export.** Download the extracted table as CSV.

## FAQ

### How do capture groups become columns?

Each parenthesized group in your regex becomes a column, so a pattern that captures timestamp, level, and message produces a three-column table.

### Can it handle large log files?

Yes. A worker streams files up to around 200MB, so big logs are processed without freezing the tab or hitting a server limit.

### Is my file uploaded to extract from it?

No. The regex runs in your browser, so the log contents stay on your device.


## Related tools

- [Log viewer](https://www.safepaper.app/data/log-viewer)
- [SQL query](https://www.safepaper.app/data/sql-query)
- [Regex playground](https://www.safepaper.app/dev/regex-playground)
- [PDF → CSV](https://www.safepaper.app/data/from-pdf)

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Canonical HTML: https://www.safepaper.app/data/regex-extract
Markdown: https://www.safepaper.app/data/regex-extract.md

There is no upload endpoint — your files are processed in this browser tab. Open your network tab and check.