Domain Check

Batch domain availability checker via whois.com with automatic CAPTCHA handling.

Also works as a Claude Code Skill for AI-assisted domain checking.

Features

• Batch check - Check multiple domains from command line or file
• Auto CAPTCHA - Automatically clicks reCAPTCHA checkbox and submit button
• Persistent profile - Reduces repeated CAPTCHA challenges across runs
• JSON output - Export results for further processing
• nslookup corroboration - Optional DNS verification for available domains

Installation

git clone https://github.com/simp-lee/domain-check-skill.git
cd domain-check-skill
npm run setup

This installs dependencies and downloads Chromium for Playwright.

Usage

Check domains from command line

node run.js scripts/domain-check.js --domains "example.com,myapp.ai,startup.io"

Check domains from file

node run.js scripts/domain-check.js --file domains.txt --out results.json

File format (one domain per line, # for comments):

# My domain candidates
example.com
myapp.ai
startup.io

With persistent browser profile (recommended)

node run.js scripts/domain-check.js --domains "example.com" --user-data-dir ./profile

Using a persistent profile reduces repeated CAPTCHA challenges.

Options

Option	Description	Default
--domains	Comma-separated list of domains	-
--file	Path to file with domain list	-
--out	Output JSON file path	(temp file)
--nslookup	Run nslookup for available domains	false
--headless	Run browser in headless mode	false
--delay	Delay between checks (ms)	900
--timeout	Page load timeout (ms)	45000
--user-data-dir	Persistent browser profile path	-
--challenge-wait	Max wait for CAPTCHA solve (ms)	120000
--challenge-poll	CAPTCHA polling interval (ms)	1500

Output

Terminal output:

example.com     available
myapp.ai        registered
startup.io      available

JSON output:

[
  { "domain": "example.com", "status": "available", "nslookup": null },
  { "domain": "myapp.ai", "status": "registered", "nslookup": null },
  { "domain": "startup.io", "status": "available", "nslookup": null }
]

Status values

Status	Description
available	Domain appears to be unregistered
registered	Domain is already registered
unknown	Could not determine status
error	Error occurred during check

How it works

1. Opens each domain's whois.com page
2. If CAPTCHA appears, auto-clicks checkbox and submit button
3. Parses page content to determine availability
4. Outputs results to terminal and optional JSON file

Use as Claude Code Skill

Add the domain-check-skill/ folder to Claude Code, then simply ask:

"Check if these domains are available: example.ai, myapp.io"

Claude will automatically use this skill to check domain availability.

Notes

• Runs checks sequentially to reduce anti-bot triggers
• Visible browser mode (headless=false) is default for CAPTCHA handling
• If auto-click fails (e.g., image CAPTCHA), you can solve manually and press Enter

License

MIT