What Caddy does

Caddy is an open-source web server written in Go and distributed since 2014, designed to serve sites over HTTPS by default with fully automatic TLS certificate issuance, renewal, and management via its proprietary CertMagic library. The product offers a reverse proxy with 9+ load balancing algorithms and circuit breaking, a production-grade static file server, a JSON config API with ACID guarantees, and a human-friendly Caddyfile format typically 15-25% the size of equivalent NGINX configurations. Beyond core web serving, Caddy has expanded into adjacent product surfaces including an internal PKI suite and ACME server (built on Smallstep libraries), an embedded PHP application server via FrankenPHP, and pluggable storage backends (Redis, Postgres, Vault, Consul) for clustered deployments, with compliance-grade TLS defaults meeting PCI DSS, HIPAA, and NIST 800-53.

The business model is sponsorship-driven rather than license-driven. Caddy is 100% free and open source with no paywalled functionality; revenue comes from tiered GitHub Sponsorships ranging from $25/month (Indie) to $11,900/month (Enterprise+), which bundle professional support, development priority, onboarding, custom patches, and marketing benefits. The project is maintained by original author Matt Holt through Dyanim, LLC, with the Caddy trademark held by ZeroSSL GmbH, and is supported by a roster of corporate sponsors including Stripe, Tailscale, Railway, Sourcegraph, Framer, and ZeroSSL. Distribution is global and self-serve via caddyserver.com, GitHub releases, the xcaddy build tool, and platform partnerships such as Railway's one-click deploy. Customers are individual developers, DevOps engineers, and businesses of all sizes who deploy web infrastructure and need turnkey HTTPS automation, white-label SaaS providers using On-Demand TLS for customer-owned domains, and regulated enterprises that benefit from the compliance-grade default TLS configuration.

Name

Caddy

Legal name

ZeroSSL GmbH

Website

https://caddyserver.com

Company type

Private

Founded year

2014

Operating status

Operating

Headcount range

11–50 employees

Short description

Caddy is an open-source Go web server that automatically provisions and renews TLS certificates, serving developers, DevOps teams, and businesses globally through a free download model funded by tiered sponsorship subscriptions.

Ownership category

akta.pro rank

Product category

Web Server Software

SIC

Services-Computer Programming, Data Processing, Etc. (7370)

akta.pro primary industry

Developer Portals, SDKs & Documentation Platforms (BPAMADAG)

akta.pro secondary industry

Deployment, Automation & DevOps (build pipelines, contract deployment tools) (FSAPABAH)

Keywords

• Open source web server
• Automatic HTTPS
• TLS certificate automation
• Reverse proxy server
• Go web server

Headquarters

HQ city

Vienna

HQ country

Austria

HQ region

Europe

Markets served

GTM type

B2B

Offering type

Software

Cost components

Personnel, Technology or R&D, Infrastructure, Operations

Revenue model

1. Sponsorships (Professional Support Services): Caddy generates revenue through tiered sponsorship programs that provide professional support, development prioritization, onboarding, training, presentations, on-sites, custom patches/branches, and marketing benefits. All features remain free and open source with no paywalled functionality. Sponsorships range from $25/month (Indie) to $11,900/month (Enterprise+) with varying levels of support access, response guarantees, and development priority.

Pricing tiers

Go-to-market motion1 record

Distribution channels5 records

Marketing channels5 records

Core offering

Caddy is a free, open-source web server written in Go that automatically obtains and renews TLS certificates for all sites by default, eliminating manual certificate management. The server combines a reverse proxy, static file server, and modular architecture into a single statically-linked binary with no runtime dependencies. The project is sustained by tiered sponsorship programs offering professional support, development prioritization, and training to businesses, while all software features remain free with no paywalls.

Product overview

Caddy is a single unified open source web server product with two native configuration interfaces: the Caddyfile (a human-friendly shorthand format) and JSON (the native programmatic format). The core Caddy binary provides automatic HTTPS, a reverse proxy, and a static file server. Optional sponsorship tiers offer professional support and development services for businesses requiring guaranteed maintenance and assistance.

Differentiator

Problem solved

Functional benefit

Products and services

• Caddy Web Server An open source web server written in Go that serves all sites over HTTPS by default with automatic TLS certificate management, featuring a reverse proxy, static file server, and extensible modular architecture. Used by developers, sysadmins, and businesses deploying web infrastructure.
• Caddyfile Configuration Format A human-friendly configuration format for Caddy that is translated to JSON automatically, designed to be simple and concise, typically 15-25% the size of comparable nginx configurations. Aimed at developers and operators who prefer readable config over JSON.
• JSON Configuration with RESTful API Caddy's native programmatic configuration format providing automated, large-scale deployment control via a RESTful admin API with ACID guarantees. Configured through the API, exports, and CLI subcommands. Aimed at enterprises and platforms managing fleets of Caddy instances.
• Caddy Sponsorships Paid sponsorship tiers ranging from $25/month (Indie) to $11,900/month (Enterprise+) providing professional support, training, onboarding, custom development patches, prioritization, and marketing benefits for businesses and individuals using Caddy professionally.

Quantifiable outcome

• Serves HTTPS in under 1 minute from zero configuration
• +4 more outcomes

Named customers10 records

Segments3 records

Ideal customer profiles3 records

Technology focussed Yes

API detail

Has API

Yes

API docs

API detail

Core technology

AI maturity

App detail

Integration5 records

Feature18 records

Partnerships

13 partnerships are on record, tiered flagship, core and minor.

• ZeroSSLflagshipStrategic or Co-development PartnerZeroSSL is Caddy's primary sponsor and project partner. They manage Caddy's infrastructure, branding, and trademark (Caddy is a registered trademark of ZeroSSL GmbH). ZeroSSL provides certificate issuance for Caddy's automatic HTTPS feature and co-markets the project.
• SmallstepcoreTechnology or IntegrationSmallstep provides open source libraries powering Caddy's internal PKI suite and ACME server functionality. Caddy's PKI and certificate authority features are built on Smallstep's cryptographic libraries.
• FrankenPHPcoreTechnology or IntegrationFrankenPHP is a distribution of Caddy that acts as a PHP application server, delivering PHP pages approximately 4x faster than traditional php-fpm setups. The PHP interpreter is embedded within the Caddy binary.
• Ardan LabsminorStrategic or Co-development PartnerArdan Labs is listed as a community partner in association with the Caddy open source Go project. They provide Go expertise and community support.
• RailwayminorChannel Partner/ Reseller/ DistributorRailway offers one-click Caddy deployment on their platform with a dedicated deploy button and integration. Railway is a sponsor providing financial support and platform integration.
• StripeflagshipGTM or Marketing PartnerStripe is a gold-tier sponsor of the Caddy project. Their testimonial states: 'With its extensible architecture and on-line config API, Caddy powers many of Stripe's internal systems.'
• TailscaleflagshipGTM or Marketing PartnerTailscale is a sponsor of the Caddy project. Tailscale integration allows Caddy to obtain certificates through Tailscale for internal services.
• SourcegraphminorGTM or Marketing PartnerSourcegraph is a sponsor of the Caddy project.
• FramerminorGTM or Marketing PartnerFramer is a sponsor of the Caddy project.
• BytebaseminorGTM or Marketing PartnerBytebase is a sponsor of the Caddy project.
• FusionAuthminorGTM or Marketing PartnerFusionAuth is a sponsor of the Caddy project.
• ChecklyminorGTM or Marketing PartnerCheckly is a sponsor of the Caddy project.
• Hope Channel InternationalminorGTM or Marketing PartnerHope Channel International is a sponsor of the Caddy project. Their testimonial states: 'Caddy's powerful technology has enabled Hope Channel International to deliver hope to millions, reaching people in every corner of the world.'

Scale indicators1 record

Recent moves6 records

Expansion highlights6 records

Direct peers

• NGINX: NGINX is the most widely deployed open-source web server and reverse proxy, directly competing with Caddy in self-hosted web serving. Caddy explicitly positions against NGINX on configuration verbosity (Caddyfiles are 15-25% the size of equivalent nginx configs) and automatic HTTPS as a default feature.
• Apache HTTP Server: Apache is one of the original open-source web servers and a direct competitor to Caddy in the self-hosted web serving category. Caddy differentiates on memory-safe Go implementation versus Apache's C-based architecture, and on automatic HTTPS as default versus manual certificate management.
• Traefik Proxy: Traefik is an open-source reverse proxy and load balancer with automatic HTTPS (Let's Encrypt), directly comparable to Caddy for cloud-native deployments. Traefik offers a paid enterprise edition (~$20,000/year), which Caddy explicitly positions against with its 100% free open-source model plus optional sponsorship.
• HAProxy: HAProxy is a high-performance open-source load balancer and reverse proxy, directly competing with Caddy's reverse proxy and load balancing capabilities (round-robin, least connections, weighted, IP hash, etc.). Both target high-throughput, production-grade web infrastructure deployments.
• Envoy Proxy: Envoy is a CNCF-graduated open-source service proxy designed for cloud-native microservices architectures, competing with Caddy in reverse proxy and ingress controller use cases. Both target modern infrastructure deployments requiring dynamic configuration and high concurrency.
• LiteSpeed Web Server: LiteSpeed is a commercial-grade open-source web server positioned as a drop-in Apache/Nginx replacement, competing directly with Caddy for performance-sensitive web hosting workloads. Both target sites requiring high concurrency and HTTPS support.

Broad incumbents

• Cloudflare: Cloudflare provides a broad web infrastructure platform including CDN, DDoS protection, and Workers (serverless edge compute) that increasingly encompasses web serving functionality. As an incumbent, Cloudflare competes with Caddy by bundling web infrastructure into integrated offerings, particularly for SaaS providers needing custom domain HTTPS.

Others

• Let's Encrypt: Let's Encrypt is a free, automated certificate authority that Caddy integrates with to obtain and renew TLS certificates. As Caddy's primary ACME provider, Let's Encrypt is an ecosystem enabler rather than direct competitor, though its ubiquity has raised baseline expectations for TLS automation across all web servers including Caddy's competitors.
• ZeroSSL: ZeroSSL GmbH owns the Caddy trademark and serves as Caddy's primary sponsor and project partner. ZeroSSL provides the certificate issuance infrastructure for Caddy's automatic HTTPS feature and is described as the project operator — a strategic relationship rather than direct competition, but one that creates both leverage and governance complexity.
• Smallstep: Smallstep provides open-source libraries that power Caddy's internal PKI suite, ACME server functionality, and certificate authority features. As a technology integration partner, Smallstep enables Caddy's enterprise PKI capabilities rather than competing with them directly.

Market position

Strengths4 records

Weaknesses4 records

Competitive moat5 records

Key risks5 records

Key highlights7 records

Customer concentration

• Xx.com/caddyserver
• GitHubgithub.com/caddyserver

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles2 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Caddy