Log Viewer

View, search, and analyze log files directly in your browser. Upload or paste lo...

SecureFastFree

Updated

Drop a log file here or click to browse

Supports .log, .txt, .out, .err files

or

Ctrl+Enter to load

or

Log Viewer Features

Analyze logs without installing anything

Log level filtering with counts
Regex search & highlight
Color-coded log levels
Virtual scrolling for large files
Auto-tail / follow mode
Line bookmarks & navigation
Inline JSON pretty-print
Timestamp auto-detection
Dark mode by default
Fullscreen mode
Export & copy filtered lines
100% browser-based & private

Why Use Log Viewer?

Level-Based Filtering

Instantly filter by ERROR, WARN, INFO, or DEBUG levels. Each level is color-coded with count badges so you can focus on what matters.

Regex Search & Highlight

Search with plain text or regular expressions. Matching lines are highlighted and counted. Filter to show only matching lines.

Virtual Scrolling

Handle log files with 100K+ lines smoothly. Only visible lines are rendered, keeping the viewer fast even with massive files.

Bookmarks & Navigation

Bookmark important lines by clicking line numbers. Jump between bookmarks to quickly navigate back to key events.

Common Use Cases

Why view logs online

Debug Application Errors

Filter to ERROR and WARN levels to quickly find exceptions and stack traces. Search for specific error codes or messages.

Monitor Server Logs

Load server access or application logs to check request patterns, response times, and error rates at a glance.

Security Audit

Search for suspicious patterns like failed login attempts, unauthorized access, or unusual IP addresses in security logs.

Performance Analysis

Analyze log timestamps to identify slow operations, bottlenecks, and timing patterns across your application stack.

How It Works

1

Load Log Data

Drag and drop a log file, paste log text directly, or load the sample data to explore features.

2

Filter by Level

Toggle ERROR, WARN, INFO, and DEBUG buttons to show or hide lines by severity. Each button shows a count badge.

3

Search & Analyze

Use the search bar with regex support to find specific patterns. View stats like line counts per level and time range.

4

Export Results

Download filtered lines as a text file or copy visible lines to clipboard. Share findings with your team.

Pro Tips for Log Analysis

Start with Errors

Toggle off INFO and DEBUG first to see only errors and warnings. This gives you the fastest path to finding problems.

Use Regex Patterns

Search for patterns like 'timeout|connection refused' to find multiple error types at once. Regex makes complex searches easy.

Bookmark Key Lines

Click line numbers to bookmark important entries. Then use the bookmark navigation to jump between them when correlating events.

Use Dark Mode

Dark mode (the default) reduces eye strain during long debugging sessions. The color-coded levels stand out better on dark backgrounds.

Frequently Asked Questions

The viewer auto-detects log levels from common patterns including ERROR, WARN, WARNING, INFO, DEBUG, TRACE, FATAL, CRITICAL, SEVERE, NOTICE, FINE, and VERBOSE. It works with any text-based log format.
The viewer uses virtual scrolling to handle files with hundreds of thousands of lines. Only visible lines are rendered, so performance stays smooth regardless of file size. All processing happens in your browser.
Yes. The search bar supports full JavaScript regular expressions. Type a regex pattern and matching portions of each line will be highlighted. You can also filter to show only matching lines.
Follow mode auto-scrolls to the bottom of the log, similar to running tail -f in a terminal. When new content is added (e.g., by pasting more lines), the view stays at the bottom.
Yes. Click any line number to toggle a bookmark (star icon). Use the bookmark navigation buttons to jump between bookmarked lines. Bookmarks persist as long as the current log data is loaded.
Absolutely. All processing happens entirely in your browser. Your log data is never uploaded to any server. Close the tab and the data is gone.
Yes. The viewer auto-detects inline JSON objects in log lines and lets you expand them into pretty-printed, readable format by clicking the JSON indicator.
ISO 8601 (2024-01-15T10:30:00Z), common datetime formats (2024-01-15 10:30:00), syslog-style (Jan 15 10:30:00), and Unix timestamps are all auto-detected and highlighted.
Yes. Use the Download button to save currently visible (filtered) lines as a text file. Or use Copy to copy them to your clipboard for pasting into other tools.
Yes. Toggle the wrap button to switch between word-wrapped and horizontal-scroll modes. Long lines like stack traces are easier to read with wrapping enabled.

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50M+

Files Processed

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Happy Users

4.9

Star Rating

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Uptime

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