Certgen

Certgen is a pure Ruby CLI tool to generate free SSL certificates from Let's Encrypt using DNS-01 verification. Perfect for developers and site owners who use cPanel or manually managed servers and need to upload certificates themselves.

📦 Setup

1. Clone the repository:

   git clone https://github.com/cdrrazan/certgen
   cd certgen

2. Install dependencies:

   bundle install

🌍 Global Usage (Recommended)

To run certgen from anywhere without typing the full path, create a symlink in your system bin:

sudo ln -s "$(pwd)/bin/certgen" /usr/local/bin/certgen

Now you can simply run:

certgen generate --domain example.com --email user@example.com

🚀 Usage

🔧 Generating Certificates

Run the CLI tool from the project directory:

bin/certgen generate --domain example.com --email user@example.com

This above command will overall:

1. Generate or reuse your Let's Encrypt account key
2. Create DNS-01 challenge instructions
3. Wait for your confirmation after DNS is set
4. Generate the certificate files
5. Zip them for upload to cPanel or any hosting service

🔧 Testing with Let’s Encrypt Staging

To avoid hitting rate limits during development or testing, use the Let’s Encrypt staging environment:

certgen test --domain example.com --email you@example.com

• This runs the same generation process but against the staging ACME server.
• Useful for verifying DNS setup and automation without generating real certificates.

🔄 Example Output Files

After running, your certs will be saved in:

~/.ssl_output/example.com/
├── certificate.crt
├── private_key.pem
├── ca_bundle.pem
└── cert_bundle.zip

🧪 Testing

The project uses RSpec for testing. To run the full test suite:

bundle exec rspec

The tests include mocks for the ACME API and file system, ensuring safe and fast execution.

✍️ DNS Setup

You'll be prompted to create a DNS TXT record:

Record Name: _acme-challenge.example.com
Record Type: TXT
Record Value: abc123...

Use https://dnschecker.org to confirm propagation before continuing.

✅ Requirements

• Ruby >= 3.1
• DNS management access to create TXT records
• cPanel or similar manual SSL upload support

📄 License

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

🙌 Author

Rajan Bhattarai
GitHub • Email

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🛠 Contributions and issues are welcome — feel free to open a PR or issue on GitHub!