13 Top Open-source Log File Viewers

13 Top Open-source Log File Viewers
Photo by Daniel Krueger / Unsplash

What is a log file?

A log file is a file that records events, actions, and system messages generated by various software applications, operating systems, or devices. It serves as a detailed record of activities and can be useful for troubleshooting, analysis, and auditing purposes.

What is a log file viewer?

A log file viewer is a software tool or application that allows users to open, read, and analyze log files. It provides a user-friendly interface to navigate through the log data, search for specific events, and filter information based on various criteria.

Log file viewers are important because they help in understanding the behavior of software applications, identifying errors or issues, and diagnosing problems. They provide insights into system performance, security incidents, and operational issues.

Benefits of using log file viewers

The benefits of using a log file viewer include:

1. Troubleshooting

Log file viewers help in identifying and resolving software errors, crashes, or performance issues by analyzing the log data.

2. Analysis and Monitoring:

Log file viewers enable users to monitor system activities, track user actions, and analyze trends or patterns in the log data for optimization or security purposes.

3. Auditing and Compliance

Log file viewers assist in compliance with regulations by providing a record of system activities, access logs, and security events.

Who uses Log Viewers?

a herd of horses standing on top of a grass covered field
Photo by Christine Mendoza / Unsplash

Various professionals across industries use log file viewers, including developers, system administrators, network engineers, security analysts, and quality assurance teams.

They rely on log file viewers to gain insights, debug issues, and ensure the smooth operation of software applications and systems.

1️⃣

Live Log Viewer (Windows)

Live Log Viewer
Live Log Viewer

LogViewer is a C# .NET application that uses WPF to monitor log files. It can track file changes, renaming, deletion, and creation, displaying appended text.

GitHub - alexwiese/LiveLogViewer: Live Log Viewer
Live Log Viewer. Contribute to alexwiese/LiveLogViewer development by creating an account on GitHub.

2️⃣

LogViewer (Windows)

LogViewer (Windows)
LogViewer (Windows)

LogViewer is a free open-source app that reads logs from UDP or text files using the Log4j/NLog template. It supports searching, filtering, and other useful features such as exporting and importing log files, sorting and filtering, and different color themes.

LogViewer (Log4j, NLog)
Download LogViewer (Log4j, NLog) for free. Reading logs from UDP or text file using the Log4j/NLog template. Software support searching, filtering and many other useful feature.

3️⃣

Java Log Viewer

Java Log Viewer
Java Log Viewer

"LogViewer" is a GUI tool for easily viewing Java application logs generated by the "java.util.logging" package. It supports filtering, sorting, and finding log records.

Java Log Viewer
Download Java Log Viewer for free. “Java log viewer” is a GUI to easily view the java application logs generated by the “java.util.logging” package. The log must be formatted by the XMLFormatter class.

4️⃣

Open Log Viewer

LogViewer is a multi-platform log viewer built with Electron and styled with Material Design. It supports multiple opened files in tabs, tailing file changes, filtering log levels, colored log entries, and customization of log levels pattern and color.

GitHub - tmoreno/open-log-viewer: A multi-platform log viewer built with Electron and styled with Material Design
A multi-platform log viewer built with Electron and styled with Material Design - GitHub - tmoreno/open-log-viewer: A multi-platform log viewer built with Electron and styled with Material Design

5️⃣

LNAV – The Logfile Navigator
LNAV – The Logfile Navigator

The Log File Navigator app, or lnav for short, is a super cool log file viewer made for small-scale usage. It's a really powerful terminal app that easily analyzes your log files, helping you find and fix issues with hardly any effort or setup needed.

Key Features

  • Log messages from different files are collated together into a single view
  • Automatic detection of log format
  • Automatic decompression of GZip and BZip2 files
  • Filter log messages based on regular expressions
  • Use SQL to analyze your logs
GitHub - tstack/lnav: Log file navigator
Log file navigator. Contribute to tstack/lnav development by creating an account on GitHub.

6️⃣

ULogViewer (Cross-platform)

ULogViewer is a powerful, cross-platform universal log viewer built using C# and .NET. It excels at reading, parsing, and analyzing different types of logs.

Supported Log Data Sources

  • Standard Output (stdout)
  • Files
  • Windows Event Log Windows
  • Windows Event Log File v3.0+
  • HTTP/HTTPS
  • TCP (without SSL)
  • UDP
  • SQLite Database
  • Azure CLI Pro
  • MySQL Database Pro
  • SQL Server Database Pro
  • Log Data Source Script Pro
  • Embedded log Data Source Script Prov3.0+
  • License: MIT License.
GitHub - carina-studio/ULogViewer: Cross-Platform Universal Log Viewer.
Cross-Platform Universal Log Viewer. Contribute to carina-studio/ULogViewer development by creating an account on GitHub.

7️⃣

Compact Log Format Viewer

Compact Log Format Viewer
Compact Log Format Viewer

This is an open-source cross platform tool to read & query JSON aka CLEF log files created by Serilog.

GitHub - warrenbuckley/Compact-Log-Format-Viewer: A cross platform tool to read & query JSON aka CLEF log files created by Serilog
A cross platform tool to read & query JSON aka CLEF log files created by Serilog - GitHub - warrenbuckley/Compact-Log-Format-Viewer: A cross platform tool to read & query JSON aka CLEF log…

8️⃣

LogViewer (Windows)

LogViewer (Windows)
LogViewer (Windows)

LogViewer is a tool for opening, viewing, and searching large text files, making it suitable for handling even very large files.

Key Features

  • Very fast
  • Supports huge files
  • Cumulative search
  • Can disable/enable search terms that are cumulative and the results are displayed instantly
  • Export current view
  • Show/Hide matched lines
  • Four search modes (Sub String Case Insensitive, Sub String Case Sensitive, Regex Case Insensitive, Regex Case Sensitive)
GitHub - woanware/LogViewer: LogViewer for viewing and searching large text files...
LogViewer for viewing and searching large text files... - GitHub - woanware/LogViewer: LogViewer for viewing and searching large text files…

9️⃣

LogViewer (Web)

LogViewer
LogViewer

LogViewer is a web application that allows real-time monitoring of server logs in the browser. It offers a powerful UI with features such as highlighting, filtering, search, and merging multiple logs into one view. LogViewer can handle large log files efficiently by only reading the part of the file that the user is viewing, without indexing.

Key Features

  • Highlight important fields, lines, and parent brackets to improve readability.
  • Filter events based on level, logger, date, thread, etc. Custom filtering conditions can also be written in JavaScript. More details
  • Merge events from multiple log files into a single log. If log files are on different machines, all machines must have LogViewer installed.
  • Fold secondary information such as irrelevant parts of exception stack traces and full logger names.
  • Automatically detect the log file format.
  • Generate a permanent link to a specific log position. This link can be copied and shared with other users.
GitHub - sevdokimov/log-viewer: Web UI for viewing logs
Web UI for viewing logs. Contribute to sevdokimov/log-viewer development by creating an account on GitHub.

🔟

Tailviewer

Windows, Recommended
Tailviewer
Tailviewer

Tailviewer is a free and open-source log file viewer that is supported on Windows 7, 8, and 10. It requires .NET 4.7.1 or higher.

Tailviewer can display any text based log file and allows tailing, searching and filtering.

Features

  • Multiline log entries
  • Searching
  • Filtering (substring, wildcard & regexp)
  • Filter by timestamp range
  • Filtering by log level (fatal, error, warning, info and debug)
  • Highlighting by log level
  • Merging multiple files (by timestamp)
  • Bookmarks
  • Additional columns:
    • Elapsed time between log entries
    • Elapsed time since first log entry
  • Plugin system to support custom/proprietary formats (submitting an issue/mr is also an option, if I have the time)
GitHub - Kittyfisto/Tailviewer: Open source log file viewer
Open source log file viewer. Contribute to Kittyfisto/Tailviewer development by creating an account on GitHub.
Tailviewer by Kittyfisto

1️⃣1️⃣

Remote Log Viewer

Cross-platform
Remote Log Viewer
Remote Log Viewer

Remote Log Viewer is a powerful and user-friendly app that utilizes server/client technology. With RLogView, you can effortlessly search and track (tail) log files on remote machines using the intuitive Java-based GUI client.

  • License: GNU General Public License version 2.0 (GPLv2)
Remote Log Viewer
Download Remote Log Viewer for free. Using the server/client technology, RLogView enables you to search and track (tail) the log files located on the remote machines using the java based GUI client.

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logview4net

logview4net

logview4net is a powerful free log viewer/log monitor that efficiently handles data from multiple sources. It excels in its ability to listen to UDP, tail files, tail SQL tables, monitor the eventlog, and watch RSS and Atom feeds.

Additionally, logview4net is specifically designed to work seamlessly with the Microsoft .NET Framework 2.0, ensuring optimal performance and compatibility.

logview4net
Download logview4net for free. logview4net is a log viewer/log monitor for data created by various sources. It can listen to UDP, tail a file, tail a SQL table, monitor the eventlog and watch RSS and Atom feeds.

1️⃣3️⃣

Free Log File Viewer: Log4Net Log4J NLog

Free Log File Viewer or GamutLogViewer© is a Windows application that serves as a log file viewer for Log4J, Log4Net, NLog, and user-defined formats including ColdFusion. It offers features such as filtering, highlighting, searching, bookmarks, and custom configurations.

  • License: GNU Library or Lesser General Public License version 2.0 (LGPLv2)
Free Log File Viewer: Log4Net Log4J NLog
Download Free Log File Viewer: Log4Net Log4J NLog for free. GamutLogViewer© is log file, logfile, viewer that works with Log4J, Log4Net, NLog, and user defined formats including ColdFusion. It supports filtering, searching, highlighting and many other useful features.


Bonus

AWStats

AWStats is not a log file viewer. It is an open-source web analytics reporting tool that analyzes and generates statistics from log files produced by web servers. AWStats provides detailed information about website visitors, such as their geographical location, operating systems, browsers, and more. It helps website administrators understand their website's traffic and user behavior. However, it does not provide the functionality of directly viewing and analyzing log files like a log file viewer does.

AWStats - Open Source Log File Analyzer for advanced statistics (GNU GPL)
AWStats Official Web Site - Compile and generate advanced graphical web, ftp or mail statistics with a logfile analysis (For IIS, Apache,... distributed under GNU GPL).

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