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Nginx Log Analyzer

Parse and filter Nginx access and error logs online โ€” free, and nothing leaves your browser

Free Online Nginx Log Analyzer

Paste an Nginx access.log or error.log and read it as structured entries instead of raw text. The analyzer understands the default Nginx combined log format โ€” $remote_addr - $remote_user [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent" โ€” and pulls out the client address, timestamp, request line, and status code from every line. Responses in the 5xx range are classified as errors and 4xx as warnings, so a failing endpoint stands out immediately rather than hiding in thousands of successful requests. Everything is parsed in your browser: the log never gets uploaded, which matters because access logs contain visitor IP addresses and often session identifiers in query strings.

Key Features

  • Parses the default Nginx combined log format, including referrer and user-agent fields
  • Reads both access.log and error.log without any configuration
  • Classifies 5xx responses as errors and 4xx as warnings so failures surface first
  • Filter by severity, then narrow further with a keyword search across the request line
  • Export the filtered result to JSON, CSV, or plain text for a spreadsheet or script
  • Runs entirely client-side โ€” visitor IPs and URLs in your logs never leave your machine
  • Free, no sign-up, and no file-size limit imposed by an upload quota

Common Use Cases

  • Finding the request that produced a 502 Bad Gateway after a deploy
  • Confirming whether a spike in traffic was real users or a single crawler
  • Tracing which upstream endpoint started returning 500s and when it began
  • Checking that a new location block is matching the URLs you expect
  • Auditing 404s to find broken internal links or missing static assets
  • Reviewing a log excerpt from a production server without copying it to a third-party service

Frequently Asked Questions

How do I analyze an Nginx log file online?

Paste the contents of your access.log or error.log into the box above and click Parse Logs. Each line is broken into a timestamp, request, and status code, and you can then filter by severity or search for a specific path. Use the Load sample button to see the output shape before pasting your own data.

Where are Nginx log files stored?

On most Linux distributions Nginx writes to /var/log/nginx/access.log and /var/log/nginx/error.log. The exact paths come from the access_log and error_log directives, which may be set globally in /etc/nginx/nginx.conf or overridden per server block in a site config.

What is the Nginx combined log format?

The default combined format is: $remote_addr - $remote_user [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent". It captures the client IP, the timestamp, the request line, the HTTP status code, the response body size, the referring page, and the browser user agent. This analyzer expects that layout.

Is my Nginx log data uploaded to a server?

No. Parsing happens in your browser in JavaScript. Nothing is sent anywhere, so the IP addresses, URLs, and any tokens embedded in query strings in your log stay on your device.

Can I analyze an Nginx error log as well as an access log?

Yes. Error log lines are parsed and classified by their severity keyword, so you can filter down to just the error and warning entries and read them alongside the failing requests from the access log.

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100% private. All processing happens in your browser. Your data never leaves your device โ€” no server uploads, no accounts required, no tracking.