Zero - Go ACME Client for ZeroSSL

Problem

Nginx servers need SSL/TLS certificates for secure connections. Existing solutions like Certbot are often too large and complex for simple setups.

Solution

Zero is a lightweight Go ACME client for obtaining and renewing SSL/TLS certificates from ZeroSSL using the ACME protocol.

Features

• Obtains and renews SSL/TLS certificates from ZeroSSL
• Supports HTTP-01 challenge
• Automatic renewal before expiration
• Minimal dependencies
• Automatic retrieval of ZeroSSL credentials using email
• Configurable certificate storage directory
• POSIX-compatible command-line interface

Requirements

• Go 1.16 or later

Installation

go install github.com/yarlson/zero@latest

Usage

zero -d example.com -e user@example.com [-c /path/to/certs] [-i] [-r]

or using long-form flags:

zero --domain example.com --email user@example.com [--cert-dir /path/to/certs] [--issue] [--renew]

Options:

• -d, --domain: Domain name for the certificate (required)
• -e, --email: Email address for credential retrieval and account registration (required)
• -c, --cert-dir: Directory to store certificates (default: "./certs")
• -i, --issue: Force issuance of a new certificate
• -r, --renew: Force renewal of an existing certificate

Without --issue or --renew, Zero checks the existing certificate and renews if needed.

For more information, run:

zero --help

Configuration

Certificates are stored in the ./certs directory by default. Use the --cert-dir flag to specify a custom directory for certificate storage.

Limitations

• Only supports HTTP-01 challenge
• Designed for single-domain certificates
• No support for wildcard certificates

Contributing

Contributions are welcome. Please submit pull requests with clear descriptions of changes and updates to tests if applicable.

License

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