Log-Viewer

Log-Viewer is a web-based viewer for JSON logs.

It provides a lightweight local UI to inspect line-delimited JSON log files from one or more folders, with quick filtering, dynamic columns, and file selection directly in the browser.

Features

• Browse multiple configured log folders
• Open a single log file or aggregate all supported files in a folder
• Support arbitrary JSON records without a fixed schema
• Generate columns dynamically from the keys found in the loaded records
• Filter by free text and per-column values
• Show source file and line number for each parsed record
• Surface parsing or file-read warnings without stopping the view

Configuration

Create config.json starting from config-blank.json and set the folders you want to browse:

{
    "serverPort": 3333,
    "logFolders": [
        {
            "name": "Local Test",
            "path": "/absolute/path/to/logs"
        },
        {
            "name": "My App",
            "path": "/absolute/path/to/my/app/logs/folder"
        }
    ]
}

Run

The app starts on 127.0.0.1:<serverPort> and serves the UI at /log-viewer.

Expected Log Format

Each non-empty line should contain a valid JSON value.

• JSON objects are shown as dynamic columns based on their keys
• Non-object values such as arrays, strings, numbers, or booleans are shown in a value column
• Nested objects and arrays are rendered as compact JSON inside the relevant cell
• The viewer adds source file and line number metadata to every parsed record

Supported file extensions:

• .log
• .json
• .jsonl
• .ndjson

Notes:

• Logs are still read line by line, so pretty-printed multi-line JSON records are not supported
• When a timestamp-like field is present, the viewer tries to sort by time using common keys such as time, timestamp, ts, and similar variants