Log Parser & Viewer

Open any log file in your browser — parse structured fields, filter by severity and time, search across millions of lines, and highlight patterns. Supports syslog, nginx, JSON, Docker, and custom formats. Nothing is uploaded — your logs stay on your machine.

Open Log Parser

Your data never leaves your browser

Supported Log Formats

Syslog (RFC 3164) Nginx access & error JSON lines Docker logs Apache access Plain text + custom formats

Features

📂

Drag & Drop

Open any text-based log file by dragging it onto the page or clicking to browse.

🔍

Smart Format Detection

Automatically detects syslog, nginx, JSON lines, Docker, and other common log formats.

⚡

Real-Time Filtering

Filter by severity level, time range, text search, or any parsed field. Results update instantly.

🎨

Custom Highlighting

Create highlighting rules to visually mark important patterns in your logs.

🛠️

Custom Formats

Define your own log format with the built-in format constructor for non-standard log files.

🔒

Fully Private

Your log files never leave your browser. Zero network requests — works offline after loading.

How to Use

1

Open a log file

Drag and drop a .log, .txt, or .json file onto the page, or click to browse your filesystem.
2

Review detected format

The parser auto-detects the log format and parses fields like timestamp, severity, hostname, and message. Adjust the format if needed.
3

Filter and search

Use the filter panel to narrow down by severity level, time range, or free-text search across all fields.
4

Highlight patterns

Create color-coded highlighting rules to spot recurring errors, specific IPs, or any pattern at a glance.

What is a Log Parser?

A log parser is a tool that reads raw log files and extracts structured data from each line — fields like timestamp, severity level, hostname, process name, and the message body. Without parsing, log files are just walls of unstructured text that are difficult to search, filter, or analyze.

Different systems produce logs in different formats. Linux servers use syslog, web servers like nginx and Apache have their own access and error log formats, Docker containers output JSON lines, and many applications define custom formats. A good log parser recognizes these formats automatically and presents the data in a structured, filterable table.

This tool runs entirely in your browser — it reads your log files using the File API, parses them with JavaScript, and displays the results in a virtual-scrolling table that handles millions of lines efficiently. No data is ever sent to a server, making it safe for production logs, security-sensitive data, and air-gapped environments.

Ready to analyze your logs?

Drop a file and start filtering in seconds. No signup, no upload, no limits.

Open Log Parser

FAQ

What log formats are supported?

The parser auto-detects syslog (RFC 3164), nginx access and error logs, JSON lines, Docker container logs, and plain text. You can also define custom formats using the built-in format constructor with regex-based field extraction.

Is there a file size limit?

There is no hard limit. Since all parsing happens in your browser, the practical limit depends on your device's available memory. Files up to 50-100 MB typically work well on modern machines.

Are my logs uploaded to a server?

No. The tool runs entirely in your browser with zero network requests. Your log files are never uploaded, stored, or transmitted anywhere. It even works offline after the page loads.

Can I save my custom formats and highlight rules?

Yes. Custom format definitions and highlighting rules are saved in your browser's localStorage. You can also export them as JSON files and import them on another machine.

Does the tool support live/streaming logs?

Currently, the tool works with static log files. You open a file and analyze it. Live tail / streaming from a running process is not supported yet.