subjs

subjs fetches javascript files from a list of URLS or subdomains. Analyzing javascript files can help you find undocumented endpoints, secrets, and more.

It's recommended to pair this with gau and then linkfinder. Or even gofuzz.

Resources

• Usage
• Installation

Usage:

Examples:

$ cat urls.txt | subjs 
$ subjs -i urls.txt
$ cat hosts.txt | gau | subjs

To display the help for the tool use the -h flag:

$ subjs -h
Usage of subjs:
  -c int
        Number of concurrent workers (default 10)
  -i string
        Input file containing URLS
  -insecure
        Skip TLS certificate verification
  -t int
        Timeout (in seconds) for http client (default 15)
  -ua string
        User-Agent to send in requests
  -ua-strategy string
        UserAgent selection strategy (rotation/random/weighted) (default "rotation")
  -version

UserAgent Selection Strategies

subjs now supports three UserAgent selection strategies:

• rotation (default): Round-robin rotation through UserAgent pool - maintains consistency and is memory efficient
• random: Pure random selection from the comprehensive UserAgent pool - maximum diversity
• weighted: Weighted random selection based on real-world browser usage statistics - most realistic distribution

Examples:

$ subjs -i urls.txt -ua-strategy random    # Random UserAgent for each request
$ subjs -i urls.txt -ua-strategy weighted  # Weighted random based on browser popularity
$ subjs -i urls.txt                        # Default rotation strategy

Advanced Features

Enhanced Error Handling:

• Comprehensive error types and structured error reporting
• Exponential backoff retry logic with jitter to prevent thundering herd
• Robust URL validation and normalization
• Per-request timeout context
• Proper resource cleanup and graceful shutdown

Improved UserAgent Pool:

• 20+ modern UserAgent strings covering Chrome, Firefox, Safari, Edge
• Support for Windows, macOS, Linux, and mobile platforms
• Includes legacy UserAgents for compatibility testing

Installation

From Source:

git clone https://github.com/geeknik/subjs
cd subjs
go build .
go install
subjs -version

Original author: lc