This article was accepted into the corpus but its outbound wikilinks were never NER-processed — typical at the deepest BFS hop or when the run's entity cap was reached. No expansion funnel to show.
| Caddy | |
|---|---|
| Name | Caddy |
| Developer | Matthew Holt |
| Released | 2015 |
| Programming language | Go |
| Operating system | Cross-platform |
| License | Apache License 2.0 |
Caddy Caddy is a web server and reverse proxy written in Go, notable for automatic HTTPS, modular design, and simple configuration. It competes with servers and proxies such as Nginx, Apache HTTP Server, HAProxy, Traefik, and Envoy (software), and is used in contexts ranging from GitHub-hosted projects to enterprise deployments at companies like DigitalOcean and Cloudflare. The project intersects with ecosystems including Docker, Kubernetes, Let's Encrypt, and Prometheus.
Caddy provides automatic TLS certificate issuance via Let's Encrypt, extensible modules, and a human-friendly configuration file. The server runs on platforms including Linux, FreeBSD, Windows, macOS, and within containers orchestrated by Docker Swarm and Kubernetes. It integrates with observability tools such as Prometheus, Grafana, ELK Stack, and supports modern web protocols like HTTP/2 and HTTP/3 (QUIC). Major contributors include community members from organizations like HashiCorp, Red Hat, Canonical (company), and Mozilla.
Development began in the mid-2010s by Matthew Holt, responding to challenges with configuring Nginx and manual TLS management. Early releases emphasized secure defaults and automatic HTTPS using Let's Encrypt's ACME protocol. Adoption accelerated as containerization with Docker and orchestration with Kubernetes became mainstream, while projects like Traefik and Envoy (software) provided alternative models. The project has been influenced by discussions around HTTP/2 adoption, the introduction of QUIC by IETF, and operational tooling promoted by DevOps practitioners from firms such as Google, Facebook, Amazon Web Services, and Microsoft.
Caddy is implemented in Go (programming language), employing a modular architecture with pluggable modules for logging, load balancing, and request processing. Core features include automatic TLS via ACME and Let's Encrypt, reverse proxying competing with HAProxy and Nginx, static file serving akin to Lighttpd, and support for TLS 1.3 standardized by IETF. It exposes metrics for Prometheus and supports distributed configuration through APIs used by automation systems like Ansible, Terraform, Puppet, and Chef. The server includes middleware patterns comparable to those in Express (web framework) and NGINX Unit, and integrates with certificate management solutions such as HashiCorp Vault.
Caddy configuration uses a declarative Caddyfile or JSON formats, enabling compatibility with CI/CD pipelines from Jenkins, GitLab CI/CD, Travis CI, and CircleCI. Users embed Caddy in stacks with Docker Compose, deploy on cloud providers such as Amazon Web Services, Google Cloud Platform, Microsoft Azure, and serve applications built with frameworks like React (JavaScript library), Vue.js, Django, Ruby on Rails, Node.js, ASP.NET Core, and Flask. Automated certificate issuance interacts with domain registrars and DNS providers like Cloudflare, GoDaddy, Namecheap, and Route 53. Operators manage secrets via systems such as Vault (software) and container orchestration platforms like Nomad (software).
Caddy emphasizes secure defaults, shipping with TLS 1.3 and modern cipher suites recommended by IETF and organizations like OWASP. Performance characteristics compare favorably in benchmarks against Nginx and Apache HTTP Server for certain static workloads and TLS termination scenarios; results are often measured with tools such as wrk, ab (ApacheBench), and Siege (software). Caddy supports HTTP/3 (QUIC) implementations informed by IETF QUIC standards and research from Cloudflare and Google on QUIC performance. Security hardening practices align with recommendations from CIS benchmarks and are often validated by vulnerability scanners from vendors like Qualys and Tenable.
A rich plugin ecosystem provides integrations with logging backends like Elastic (company), Splunk, and Datadog, observability via Prometheus and Grafana, and service discovery through Consul (software), etcd, and ZooKeeper. Caddy is packaged for distributions maintained by Debian, Ubuntu, Fedora, and Arch Linux maintainers, and appears in infrastructure-as-code examples using Terraform providers and Helm charts for Kubernetes. CI/CD and deployment patterns reference GitOps tools such as Argo CD and Flux (software), while security-conscious teams integrate with Keycloak, OAuth 2.0, and OpenID Connect providers.
Caddy is used by a spectrum of users from hobbyists on Raspberry Pi to enterprises and research projects at institutions like MIT, Stanford University, and UC Berkeley for hosting internal tools. Companies and platforms that have employed Caddy or referenced it in architecture discussions include DigitalOcean, Cloudflare, Fastly, Heroku, Elastic (company), and Linode. Community projects on GitHub and GitLab demonstrate integrations with Nextcloud, Matrix (protocol), Mattermost, and self-hosting stacks such as Home Assistant and OpenMediaVault. The project has been discussed at conferences including KubeCon, FOSDEM, GopherCon, and DevOpsDays.
Category:Web server software