Log File Analyzer
Analyze large log files entirely in your browser. Upload a log, filter by keyword or regex, narrow by time range, get ERROR/WARN/INFO counts, a timeline distribution chart, pattern aggregation, and export the filtered result. Files are streamed locally with FileReader + ReadableStream — nothing is uploaded to any server.
Filters
Statistics
Timeline
Top patterns (aggregated)
Log lines (showing first 200 of filtered)
How to use the Log File Analyzer
Upload a log file and get an instant overview: level counts, a timeline distribution, aggregated patterns, and a filterable list — all processed locally in your browser with streaming (FileReader + ReadableStream), so even very large files won't be fully loaded into memory or sent to any server.
What it does
- Level counts — total lines plus ERROR / WARN / INFO / DEBUG / OTHER tallies.
- Timeline — a bar chart showing how many log lines fall in each time bucket (uses timestamps like 2026-10-25 10:00:00; falls back to line-number buckets if no timestamp is found).
- Pattern aggregation — similar messages (numbers, quotes and hex replaced with placeholders) are merged and counted, revealing the most frequent repeating errors.
- Filter — by keyword, regex, level, and a start/end time range. Export filtered downloads the matching lines as a text file.
Recommended log format
One log entry per line. The tool recognises timestamps such as 2026-10-25 10:00:00 or ISO 8601, and severity keywords like ERROR, WARN, INFO, DEBUG. Lines without a recognised timestamp are still analysed for level and counted.
Everything runs locally — your log data never leaves the page.