# Local log viewer — search big logs, no upload

> Browse and search big log files with virtual scrolling, filter and highlight terms, and copy lines — all with chunked reads in your browser. No upload.

Open big log files and search them with a virtualized line list, filter and highlight terms, and copy individual lines — using chunked reads so huge files stay responsive. Everything runs on your device.

Production logs are too big for most editors and too sensitive for random online viewers. This viewer reads them in chunks with virtual scrolling, so you can search, filter, and copy lines from huge files right in the browser.

When you want to extract structured fields rather than read lines, switch to the Regex extractor; to query the results, use SQL.

## How to

1. **Add a log file.** Drop a large .log or .txt file.
2. **Search & filter.** Enter terms to filter and highlight matching lines.
3. **Copy lines.** Copy any line you need for a ticket or report.

## FAQ

### Can it open very large logs?

Yes. Chunked reads and a virtualized list mean multi-hundred-megabyte logs scroll smoothly instead of freezing the browser.

### Can I highlight search terms?

Yes — filter to matching lines and highlight the term within them, so you can trace an error across a big file quickly.

### Is my log uploaded to view it?

No. The file is read in chunks locally, so its contents never leave your device — important for production logs.


## Related tools

- [Regex extractor](https://www.safepaper.app/data/regex-extract)
- [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/log-viewer
Markdown: https://www.safepaper.app/data/log-viewer.md

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