Log Analyzer & Viewer

Analyze production logs privately. Filter by level, search for keywords, and find errors instantly. 100% local.

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Drop a log file here or Click to Upload

ALL ERROR WARN INFO DEBUG
Awaiting log data. Upload a file or paste text below.

What is the Log Analyzer & Viewer?

The Log Analyzer & Viewer is a client-side log auditing dashboard designed to view, parse, and filter large application log files. By parsing raw text streams in browser memory, developers can inspect stack traces, analyze status codes, and separate errors from standard debug records.

This analyzer manages all file reads, line-by-line matches, and keyword filters locally on your computer. Because no log files, system paths, or pasted transaction strings are transmitted to remote servers, your system architectures and diagnostic details remain private.

How to Use the Log Analyzer & Viewer

  1. Upload Your Log File: Click the "Choose File" button or drag-and-drop a .log or .txt file into the file input area.
  2. Or Paste Raw Logs: Alternatively, paste log text strings directly into the "Paste Log Text" box and click "Process Paste".
  3. Filter by Severity: Use the log level dropdown to filter and view specific categories (All, Info, Warn, Error, Debug).
  4. Query Specific Keywords: Type terms (like transaction IDs, IP addresses, or method names) into the search bar to isolate matching entries.
  5. Audit Outputs: Inspect the high-contrast parsed logs list to trace application heartbeats and identify warning states.

Key Features

  • Client-Side File Parsing: Opens and parses local text files using browser-side readers without uploading files.
  • Log Level Filtering: Sorts logs by typical level strings (INFO, WARN, ERROR, DEBUG) instantly.
  • Interactive Search Filter: Refines displayed records as you type to speed up troubleshooting.
  • Flexible Input Methods: Supports both local file uploads and direct copy-pasting of raw console dumps.
  • 100% Secure Auditing: Isolates log parsing inside a local browser sandbox to prevent data leaks.

Common Use Cases

  • Debugging Server Crashes: Search production server logs for fatal errors and inspect stack traces to identify crashes.
  • Access Log Audits: Scan web access logs (like Nginx or Apache) for unauthorized IP access, brute-force attempts, and 404 links.
  • API Transaction Checks: Filter transaction IDs to track request-response cycles across services.
  • Local Build Inspections: Audit build tool console outputs to debug compiling warnings.

Frequently Asked Questions

The parser handles files up to 100MB in browser memory. For massive logs (e.g., gigabyte-scale logs), we recommend using command-line filters (like grep) before uploading logs to this tool.

No. 99tool.in processes all log streams locally in your browser tab. Your files, system paths, and errors are never uploaded, stored, or analyzed on our servers.

Yes. Paste or load your JSON logs. While the tool renders them as raw strings, the search bar allows you to search and filter by JSON keys (e.g., "level": "error").

This version uses standard case-insensitive keyword searches for optimal performance. For regex queries, check out our specialized Regex Tester tool.

🔒 Privacy & Data Note: Log uploads, processing, and keyword searches occur locally in your browser. None of your data is sent to our servers.