Dev Tools > Log Analyzer

Log Analyzer
Apache · Nginx · Syslog · App Logs

Paste server log files to instantly detect errors, analyze HTTP status codes, find top IPs and URLs, build timelines, and surface anomalies. Runs client-side — no data leaves your browser.

Apache / Nginx Syslog / app logs Anomaly detection 100% private

Log Analyzer

Paste any log format — Apache, Nginx, syslog, JSON, or mixed application logs. Auto-detected. Up to ~50,000 lines handled efficiently.

// Log Analyzer — paste logs below
Log content 0 lines
Auto-detect Ctrl+Enter to run
0Total Lines
0Errors
0Warnings
0Successful (2xx)
0Client Errors (4xx)
0Server Errors (5xx)
0Unique IPs

Supported Log Formats

Auto-detection recognizes all common server and application log formats. Mixed-format logs are processed line by line.

FormatPatternExample
Apache CombinedIP - user [date] "method path" status size "ref" "ua"192.168.1.1 - - [15/May/2026:10:24:33 +0000] "GET /page HTTP/1.1" 200 1234
Apache CommonIP - user [date] "request" status size10.0.0.1 - admin [15/May/2026:10:00:00 +0000] "POST /api HTTP/1.1" 201 512
Nginx AccessSame as Apache combined format127.0.0.1 - - [15/May/2026:10:24:33 +0000] "GET / HTTP/2.0" 200 4567
Syslog (RFC 3164)Month Day HH:MM:SS hostname process[pid]: messageMay 15 10:24:33 web01 nginx[1234]: error connecting to upstream
Application (levelized)[datetime] LEVEL message[2026-05-15 10:24:33] ERROR Database connection failed: timeout
JSON logs{"timestamp":"...","level":"...","message":"..."}{"ts":"2026-05-15T10:24:33Z","level":"error","msg":"Connection refused"}
Generic / MixedAny line containing ERROR, WARN, INFO, DEBUG2026-05-15 10:24:33.123 [ERROR] NullPointerException at line 42

Log Analysis Guide

What to look for in server logs and how to use the analysis tabs above.

Reading Apache / Nginx logs

The Top IPs tab shows which clients make the most requests — useful for identifying crawlers, scrapers, or potential attackers. The Top Paths tab shows the most-requested URLs. Combined with the Status Codes tab, you can find which paths are returning 404s (broken links), 403s (permission issues), or 500s (server errors). Sort by 5xx codes to find critical backend problems.

Detecting anomalies

The Anomalies tab automatically detects: error bursts (sudden spike in errors), single-IP high request rates (potential DDoS or scraping), 404 storms (broken links or scan attempts), 5xx spikes (server failures), and unusual request patterns. Any IP making hundreds of requests per minute to non-existent paths is a strong indicator of automated scanning.

Using the timeline

The Timeline tab bins log entries by hour or minute to show request volume over time. A sudden spike in traffic at an unusual hour may indicate a bot attack, viral traffic, or a scheduled job gone wrong. A drop to zero indicates a server outage. Compare the timeline with error rates to correlate events.

Where to find log files

Apache: /var/log/apache2/access.log and error.log. Nginx: /var/log/nginx/access.log and error.log. syslog: /var/log/syslog or /var/log/messages. Application logs: typically in your app's logs/ directory or configured via your logging framework. Use tail -n 5000 /var/log/nginx/access.log to get recent lines.

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Log Analyzer – FAQ

What log formats does this tool support?+
Auto-detected formats: Apache Combined Log Format (IP - user [date] "request" status size "referer" "user-agent"), Apache Common Log Format, Nginx access logs (same combined format), syslog (RFC 3164: "Month Day time host process: message"), levelized application logs ([datetime] LEVEL message), JSON log lines, and generic logs containing ERROR/WARN/INFO keywords. Mixed-format files are processed line by line — each line is parsed independently.
Is my log data sent to any server?+
No. All log analysis runs entirely in your browser using JavaScript. Your log content never leaves your device and is not transmitted, stored, or processed on any server. This makes it safe to analyze logs containing sensitive information like IP addresses, authentication attempts, or internal API paths. You can verify this by checking the Network tab in your browser developer tools — you'll see no outgoing requests when you click Analyze Logs.
How do I export Apache access logs?+
On Linux servers: tail -n 10000 /var/log/apache2/access.log > recent_logs.txt to get the last 10,000 lines, then open the file and copy-paste. Or use: cat /var/log/apache2/access.log | grep "2026-05-15" to filter by date. For Nginx: tail -n 10000 /var/log/nginx/access.log. For large files, use grep to pre-filter by date, status code, or IP before pasting: grep " 500 " /var/log/nginx/access.log | tail -n 2000.
What are common log analysis use cases?+
Debugging server errors: filter for 5xx status codes to find backend failures. Security analysis: identify IPs making hundreds of requests (scraping, scanning, brute force). SEO auditing: find 404s to fix broken links or redirects. Performance investigation: find slow endpoints by checking response sizes and frequencies. Traffic analysis: see peak traffic hours from the timeline. Bot detection: identify non-browser user agents making many requests.