Nothing Leaves the Browser
Log data is loaded and processed entirely in memory. When you close the tab, nothing persists. No backend, no telemetry, no upload.
MIT • Client-Side • Offline
LogSieve
In-browser log exploration and filtering that runs entirely in the browser. Load your log files, build extractors, filter directly from the results view, and investigate without sending anything to a server.
0
Server requests at runtime
100%
Client-side processing
MIT
Open source license
Analyze Logs Without Moving Them
Designed for environments where shipping logs to an external service isn’t an option.
Air-Gap Ready
Download once and run with no internet connection. Works on isolated networks, secure facilities, and classified environments.
Filter & Search
Filter log lines by pattern, level, timestamp range, or custom criteria. Find the signal in large log files without writing grep scripts or round-tripping through a hosted search service.
Build Reusable Extractors
Turn recurring parsing logic into reusable extractor definitions so structured fields can be surfaced quickly during incident work, even when the original logs were never normalized.
Right-Click Filtering
Apply filters straight from the results grid with context-menu actions. When a field value matters, you can pivot on it immediately instead of retyping or rebuilding the filter by hand.
Action Confirmation in Context
Toast notifications confirm filter and extractor actions as you work, which keeps fast-moving investigations understandable without cluttering the screen.
Single File Deployment
One HTML file. No installation, no dependencies, no build process. Carry it on a USB drive or share it as an email attachment.
No Data Exfiltration Risk
Use LogSieve on sensitive log data without risk of exfiltration. Safe for PII, PHI, or confidential infrastructure data.
MIT Licensed
Free to use, fork, and redistribute. Audit the source yourself to verify the zero-exfiltration guarantee.
Multi-MB Log Files
Optimized for large log files with efficient in-memory data structures, lazy processing, and background workers. Analyze without waiting for a SIEM query to return.
Where LogSieve Gets Used
Incident Response
Pull logs off a compromised system, open LogSieve locally, build the extractor you need, and analyze without routing evidence through your corporate proxy or logging pipeline.
Regulated Environments
Healthcare and financial services teams can analyze logs containing PHI or PII without moving data outside the approved security boundary.
On-Call Debugging
Engineers troubleshooting production issues can load multi-MB log files directly in the browser, pivot with contextual filters, and keep moving without waiting for a SIEM query to return.
Works Well With
LogSieve is often the offline starting point. Here are good next steps when you need more.
Delve & SIEMatic
Outgrew a single HTML file? When you need central indexing, scheduled alerting, and retention across many hosts, graduate to Delve or SIEMatic.
WebUtils
It follows the same offline, single-file approach. See the rest of the toolkit including Kanban, Secret Share, Regex Workbench, and more, all zero-telemetry and local-first.
Learn More →Free to Use. Commercially Supported.
LogSieve is MIT licensed: download, use, and share freely. Commercial support contracts available for organizations that need SLA-backed maintenance and feature roadmap input.