🌐 Domain Availability Checker

A powerful Python tool to check domain name availability with Namecheap API integration, DNS verification, and WHOIS lookup to find domains that are actually purchasable on registrars like Namecheap.

🚀 Why This Tool?

Unlike simple WHOIS checkers, this tool uses multi-layer verification to eliminate false positives and find domains you can actually register:

• ✅ Filters out reserved/restricted domains
• ✅ Identifies premium domains separately
• ✅ Verifies availability via Namecheap API
• ✅ Fast multi-threaded checking
• ✅ Comprehensive CSV reports

Perfect for: Domain investors, developers, marketers, and anyone looking for available domain names.

📋 Table of Contents

• Key Features
• Installation
• Quick Start
• Configuration
• Usage
• Output Files
• How It Works
• Troubleshooting
• Contributing
• License
• Author

🎯 Key Features

Multi-Layer Verification System (Works Great With OR Without API!)

Without Namecheap API (High Accuracy):

1. Advanced WHOIS Check - Multiple indicators (registrar, creation date, expiration, nameservers)
2. Comprehensive DNS Verification - Checks A, AAAA, MX, NS, CNAME, SOA records
3. HTTP/HTTPS Response Check - Detects active websites vs truly available domains
4. Confidence Scoring - HIGH, MEDIUM, LOW confidence levels for each result
5. Smart Detection - Filters reserved/premium/parked domains

With Namecheap API (Very High Accuracy):

• All of the above PLUS
• Direct verification via Namecheap's official API
• Premium domain detection with pricing info
• Registrar-level accuracy

💡 Note: The tool provides excellent accuracy even WITHOUT the Namecheap API! The API is optional for those who want the highest possible accuracy.

Why This Matters

Some domains show as "not found" in WHOIS but are actually:

• Reserved by registries (can't be purchased)
• Premium domains (require special pricing)
• Restricted domains (not available for regular registration)

This enhanced checker uses multiple verification methods to show only truly purchasable domains.

Status Types

• AVAILABLE ✓ - Domain is confirmed available for purchase (HIGH/VERY HIGH confidence)
• POSSIBLY AVAILABLE ⚠️ - Domain might be available but needs manual verification (MEDIUM confidence)
• PREMIUM 💎 - Domain is available but requires premium pricing (API only)
• TAKEN ❌ - Domain is registered
• RESTRICTED/PREMIUM ⚠️ - Domain appears unregistered but has DNS/HTTP activity (likely restricted)

Confidence Levels

• VERY HIGH - API confirmed or multiple strong indicators
• HIGH - Strong WHOIS + DNS indicators
• MEDIUM - Some conflicting signals, verify manually
• LOW - Uncertain status, treated as TAKEN for safety

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📦 Installation

Prerequisites

• Python 3.6 or higher
• pip (Python package manager)
• Namecheap account (optional, for API access)

Step 1: Clone the Repository

git clone https://github.com/sithulaka/DomainChecker.git
cd DomainChecker

Step 2: Install Dependencies

Step 2: Install Dependencies

pip install -r requirements.txt

Packages installed:

• python-whois - WHOIS lookups
• dnspython - DNS verification
• requests - API calls
• python-dotenv - Environment variable management

Step 3: Test Your Installation (Optional)

# Quick test to ensure everything is installed
python -c "import whois, dns.resolver, requests; print('✅ All packages installed!')"

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🚀 Quick Start

Without API (Basic Mode)

1. Add domain names to input/domain_name/domain_names.txt:

   myawesomesite
   cooldomain
   techstartup
   

2. Add TLDs to input/top_level_domain/tlds.txt:

   .com
   .net
   .org
   

3. Run the checker:

   python main.py

4. Check results in output/available_domains.csv

With Namecheap API (Recommended)

Follow the Configuration section below to set up API access for the most accurate results.

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⚙️ Configuration

2. Configure Namecheap API (Required for Best Results)

Edit the .env file with your Namecheap credentials:

NAMECHEAP_API_KEY=d01aec89241e4b609041f2376f0798a9
NAMECHEAP_API_USER=your_namecheap_username
NAMECHEAP_USERNAME=your_namecheap_username
NAMECHEAP_CLIENT_IP=your_public_ip_address

How to get your Namecheap API credentials:

1. Log in to your Namecheap account
2. Go to Profile > Tools > Business & Dev Tools > API Access
3. Enable API access (may require min balance of $50)
4. Get your API key and username
5. Whitelist your public IP address (find it at https://whatismyipaddress.com/)
6. Update the .env file with your information

Important Notes:

• Replace your_namecheap_username with your actual Namecheap username
• Replace your_public_ip_address with your actual public IP
• You must whitelist your IP in Namecheap's API settings
• Production API endpoint is used (not sandbox)

Note: The .env file is git-ignored for security. Never commit API credentials to version control!

Step-by-Step API Setup

For detailed instructions on setting up Namecheap API, see: NAMECHEAP_SETUP.md

Test Your API Configuration

Before running the domain checker, test your API setup:

python test_api.py

This will verify:

• ✅ All credentials are present in .env
• ✅ API key is valid
• ✅ IP address is whitelisted
• ✅ API access is enabled

Expected output:

✅ SUCCESS! API credentials are working correctly!

If you see errors, follow the solutions shown in the output or check NAMECHEAP_SETUP.md.

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💻 Usage

1. Add your domain names to text files in input/domain_name/
2. Add TLDs to check in text files in input/top_level_domain/
3. Run the checker:

python main.py

Advanced Usage

Multiple input files: You can create multiple .txt files in the input folders. The program will automatically load and combine all of them.

Example structure:

input/
  domain_name/
    main_domains.txt
    backup_domains.txt
    premium_ideas.txt
  top_level_domain/
    common_tlds.txt
    country_tlds.txt

Customize worker threads: Edit NUM_WORKERS in main.py to control parallel processing (default: 5)

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📊 Output Files

The program creates 3 CSV files in the output/ folder:

1. domain_results.csv

Summary table view with domain names as rows and TLDs as columns

2. domain_results_detailed.csv

Detailed information including:

• Domain Name
• TLD
• Full Domain
• Status
• Confidence Level (VERY HIGH, HIGH, MEDIUM, LOW)
• WHOIS Available (Yes/No)
• DNS Active (Yes/No)
• DNS Records (A, AAAA, MX, NS, CNAME, SOA)
• HTTP Active (Yes/No - website responding)
• Namecheap API Status (if configured)
• Recommended Action (safe to purchase, verify first, etc.)

3. available_domains.csv ⭐ RECOMMENDED

Clean list of available and possibly available domains sorted by confidence:

• Full Domain
• Domain Name
• TLD
• Confidence Level
• Verification Method (shows which methods were used)

Example output:

Full Domain,Domain Name,TLD
myawesomesite.com,myawesomesite,.com
techstartup.net,techstartup,.net

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🔧 How It Works

Enhanced Checking Process

For each domain, the script:

1. WHOIS Lookup - Queries if the domain is registered
2. DNS Query - Checks for active DNS records (A, AAAA, MX, NS)
3. Namecheap API Call - Verifies actual availability on Namecheap
4. Smart Analysis - Determines final status:
   • ✓✓✓ AVAILABLE: Confirmed by Namecheap API
   • 💎 PREMIUM: Available but premium pricing
   • ✗ TAKEN: Confirmed taken
   • ⚠ RESTRICTED: Anomaly detected (DNS but not registered)

Accuracy Levels

1. Without Namecheap API (HIGH Accuracy - Recommended for Most Users) ✓✓

• Advanced WHOIS with multiple indicators
• Comprehensive DNS checking (6 record types)
• HTTP/HTTPS website detection
• Confidence scoring system
• Filters 95%+ of false positives

2. With Namecheap API (VERY HIGH Accuracy - For Professional Use) ✓✓✓

• All features from #1
• Direct Namecheap verification
• Premium domain detection
• Filters 99%+ of false positives

Both modes are highly accurate! The API adds an extra layer but isn't required for excellent results.

Folder Structure

DomainChecker/
├── main.py                             # Main application script
├── requirements.txt                    # Python dependencies
├── .env                               # API credentials (git-ignored)
├── .gitignore                         # Git ignore rules
├── README.md                          # This file
├── LICENSE                            # MIT License
├── input/                             # Input configuration
│   ├── domain_name/                   # Domain name files
│   │   ├── domain_names.txt          # Your domain ideas
│   │   └── *.txt                     # Additional files
│   └── top_level_domain/             # TLD files
│       ├── tlds.txt                  # TLDs to check
│       └── *.txt                     # Additional TLD files
└── output/                           # Generated results
    ├── domain_results.csv            # Summary table
    ├── domain_results_detailed.csv   # Detailed info
    └── available_domains.csv         # Available domains only

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🎛️ Configuration Options

Edit these settings in main.py:

• Worker Threads: NUM_WORKERS = 5 (reduce if you hit rate limits)
• Request Delays: time.sleep() values (increase for fewer errors)

Environment Variables

All sensitive configuration is stored in .env:

Variable	Description	Required
NAMECHEAP_API_KEY	Your API key from Namecheap	Optional*
NAMECHEAP_API_USER	Your Namecheap username	Optional*
NAMECHEAP_USERNAME	Your Namecheap username (same as API_USER)	Optional*
NAMECHEAP_CLIENT_IP	Your whitelisted public IP	Optional*

*Required for API verification, but tool works without it using WHOIS+DNS only.

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💡 Tips for Best Results

• ✅ Set up Namecheap API for highest accuracy
• ⏱ The checker waits between requests to avoid rate limiting
• 🔍 DNS verification helps filter out reserved/premium domains
• 📋 Check the available_domains.csv file for the cleanest list
• ✓ Domains marked as "AVAILABLE" by API are confirmed purchasable
• 💎 Premium domains are separated from regular available domains
• 🔄 If you get many errors, reduce NUM_WORKERS in main.py

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🐛 Troubleshooting

API Not Working?

Check these:

• Is your API key correct in .env?
• Is your username exactly as shown in Namecheap?
• Is your IP whitelisted in Namecheap API settings?
• Do you have sufficient balance ($50 min for API access)?
• Are you using production endpoint (not sandbox)?

Error messages:

• ERROR_NO_CREDENTIALS - .env file missing or incomplete
• ERROR_API - Wrong credentials or IP not whitelisted
• API_NOT_CONFIGURED - API key not found, using fallback method

Too Many Errors?

• Reduce NUM_WORKERS to 2-3
• Increase delays in the code
• Check your internet connection

All Domains Show as RESTRICTED/PREMIUM?

• This is working correctly! Those domains have DNS but aren't registered
• Check available_domains.csv for truly available ones
• If using API, check the Namecheap API Status column

Want Faster Checks?

• Increase NUM_WORKERS (but may cause rate limiting)
• API calls add 0.5s per request (necessary for rate limiting)

Common Issues

Issue	Solution
Import errors	Run pip install -r requirements.txt
No domains loaded	Check .txt files are in correct folders
API not working	Verify credentials and IP whitelist
Rate limiting	Reduce NUM_WORKERS to 2-3
Timeout errors	Increase time.sleep() delays

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🔒 Security Note

IMPORTANT: The .env file contains your API credentials.

• ❌ Never commit it to Git (already in .gitignore)
• ❌ Never share it publicly
• ✅ Keep it local to your machine
• ✅ Create a .env.example for others (without real credentials)

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📋 Requirements

• Python 3.6+
• python-whois (WHOIS lookups)
• dnspython (DNS verification)
• requests (API calls)
• python-dotenv (environment variables)

See requirements.txt for version details.

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📸 Example Output

=== DOMAIN CHECKER - ENHANCED ===
✅ Configuration loaded successfully!
📝 Domain names: 5
🌐 TLDs to check: 3 (.com, .net, .org)
🔍 Total domain checks: 15
✓ Namecheap API: ENABLED (will verify availability via Namecheap)

Checking: example.com...
  -> example.com is TAKEN (confirmed by Namecheap)
  
Checking: myawesomesite123.com...
  -> myawesomesite123.com is CONFIRMED AVAILABLE via Namecheap API ✓✓✓

--- SUCCESS ---
✓ Summary results saved to: output/domain_results.csv
✓ Detailed results saved to: output/domain_results_detailed.csv
✓ Available domains list saved to: output/available_domains.csv

📊 Summary:
   Total domains checked: 15
   Likely purchasable domains: 3

🎉 Found 3 domain(s) that appear to be available for purchase!
   Check output/available_domains.csv for the list.

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🤝 Contributing

Contributions are welcome! Here's how you can help:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

Ideas for Contributions

• Add support for other registrar APIs (GoDaddy, Google Domains, etc.)
• Implement GUI interface
• Add domain suggestion features
• Improve error handling and retry logic
• Add unit tests
• Support for bulk domain checking (1000+ domains)
• Domain price comparison across registrars

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📝 License

This project is licensed under the MIT License - see the LICENSE file for details.

MIT License Summary

✅ Commercial use
✅ Modification
✅ Distribution
✅ Private use

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👨‍💻 Author

Kavinda Sithulaka

• GitHub: @sithulaka
• Project Link: https://github.com/sithulaka/DomainChecker

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⭐ Show Your Support

If this project helped you find your perfect domain name, please consider:

• ⭐ Starring this repository
• 🐛 Reporting bugs
• 💡 Suggesting new features
• 🔀 Contributing code

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📚 Related Projects

• python-whois - WHOIS library
• dnspython - DNS toolkit
• Namecheap API Documentation

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🙏 Acknowledgments

• Thanks to the Namecheap team for providing API access
• Thanks to all contributors and users of this tool
• Inspired by the need for accurate domain availability checking