Caddy

Overview

Caddy is an advanced, open source web server engineered for modern web infrastructure, providing automatic HTTPS and dynamic TLS management out of the box. Written in Go, Caddy is designed for developers, teams, and enterprises who demand secure, scalable, and reliable web serving with minimal configuration overhead. Its enterprise-grade security, compliance with PCI, HIPAA, and NIST standards, and seamless certificate management make it a standout solution for both public-facing and internal services. Caddy’s unique architecture simplifies infrastructure, reduces operational costs, and boosts developer productivity.

Key Features

• Automatic HTTPS & On-Demand TLS: Instantly provisions, renews, and manages certificates for custom domains, including customer-owned domains, with zero downtime and no manual intervention. Supports internal and localhost certificates with a self-managed CA.
• Dynamic Configuration API: Offers a powerful RESTful JSON config API and Caddyfile for flexible, real-time configuration changes. Supports config adapters for compatibility with various workflows.
• Massive Scalability: Designed to handle hundreds of thousands of sites or thousands of instances, with cluster coordination for certificate management and resource sharing across fleets.
• Production-Grade Static File Serving: Delivers static files with high performance, supporting compression, virtual file systems, range requests, Etags, and directory browsing.
• Forward-Thinking Reverse Proxy: Supports HTTP, FastCGI, WebSockets, dynamic backends, and high availability, making it ideal for modern web architectures.
• Security & Compliance: Secure TLS defaults that pass PCI, HIPAA, and NIST compliance by default, with features like OCSP stapling and robust revocation handling.

Use Cases

• Developers building SaaS platforms or web applications that require seamless, secure HTTPS for custom domains and rapid deployment.
• Teams managing fleets of servers or microservices needing centralized, automated certificate management and dynamic configuration.
• Companies seeking enterprise-grade, compliant web serving for both public and internal services, including internal PKI and secure localhost development.
• Hosting providers or agencies delivering white-label solutions at scale with minimal operational overhead.

Getting Started

To begin with Caddy, download the latest release from the official website or use package managers for your platform. Installation is straightforward, and configuration can be done via the intuitive Caddyfile or the powerful JSON API. Start the server with a simple command, and Caddy will automatically obtain and renew certificates for your configured domains. Comprehensive documentation and an online config API are available to streamline setup and integration.