404 Finder

A Python tool to crawl websites and find broken links (404s) and oversized pages.

Installation

pip install 404-finder

Usage

404-finder example.com [options]

Options

• --max-size BYTES: Maximum allowed size in bytes for any page
• --workers N: Number of parallel workers (default: 10)
• --max-depth N: Maximum depth to crawl (default: no limit)
• --verbose: Enable verbose logging

Example

# Check for broken links on example.com
404-finder example.com

# Check for broken links and pages larger than 1MB
404-finder example.com --max-size 1000000

# Crawl with 20 parallel workers and verbose logging
404-finder example.com --workers 20 --verbose

Output

The tool generates a JSONL file named result_domain.jsonl containing details about each URL visited, including:

• URL
• Status code
• Page size
• Referrer (the page that linked to this URL)

Features

• Parallel crawling with configurable number of workers
• Finds broken links (HTTP status codes 4xx and 5xx)
• Checks page sizes against a configurable limit
• Follows redirects while staying within the same domain
• Handles both internal and external links
• Generates detailed JSONL reports