Caddy vs Nginx: Head-to-Head Performance & Feature Comparison (2026)

Two Web Servers, Very Different Philosophies

Nginx has been the default reverse proxy and web server for production deployments since the late 2000s. It's fast, battle-tested, and powers roughly a third of the internet. Caddy arrived in 2015 with a radical premise: what if your web server handled TLS certificates automatically, required zero configuration for HTTPS, and used a human-readable config format? In 2026, both are mature, production-grade options -- but they solve problems differently.

I've run both in production across dozens of projects. Nginx on high-traffic APIs handling 50K+ concurrent connections. Caddy on SaaS products where automatic HTTPS and simple config saved hours of DevOps work every month. This guide gives you concrete benchmarks, real config comparisons, and an honest recommendation based on your team size and workload.

What Is a Reverse Proxy?

Definition: A reverse proxy is a server that sits between client devices and backend application servers, forwarding client requests to the appropriate backend and returning the response. It handles concerns like TLS termination, load balancing, caching, compression, and rate limiting -- offloading these from your application code. Both Caddy and Nginx function as reverse proxies, static file servers, and load balancers.

The choice between Caddy and Nginx is not about capability -- both can reverse-proxy, load-balance, serve static files, and terminate TLS. The difference is in defaults, configuration ergonomics, performance at extreme scale, and the ecosystem surrounding each server.

Benchmark Methodology

All benchmarks were run on identical hardware: bare-metal AMD EPYC 7763 (64 cores), 128 GB RAM, 10 Gbps NIC, Ubuntu 24.04 LTS. Caddy 2.9.1 and Nginx 1.27.3 (open-source mainline). Load generated with wrk2 and h2load from a separate machine on the same 10G switch. Each test ran for 60 seconds after a 10-second warmup. Results are the median of five runs.

Static File Serving Performance

Serving a 4 KB HTML file and a 1 MB image over HTTPS (TLS 1.3, HTTP/2):

Metric	Caddy 2.9	Nginx 1.27	Difference
4 KB HTML - Requests/sec	285,000	310,000	Nginx +8.8%
4 KB HTML - p99 Latency	1.8 ms	1.2 ms	Nginx -33%
1 MB Image - Throughput	8.9 Gbps	9.4 Gbps	Nginx +5.6%
1 MB Image - p99 Latency	12 ms	10 ms	Nginx -17%
Memory (idle)	28 MB	6 MB	Nginx -79%
Memory (10K conn)	185 MB	62 MB	Nginx -66%

Nginx wins on raw static file performance. That C-based event loop with zero-copy sendfile is hard to beat. Caddy, written in Go, carries the overhead of the Go runtime and garbage collector. But look at the absolute numbers -- 285K requests/second for a 4 KB file is more than enough for virtually any workload. The difference only matters if you're serving static files at CDN-like scale from a single server.

Reverse Proxy Latency

Proxying to a Node.js backend returning a 512-byte JSON response over HTTP/2:

Concurrent Connections	Caddy p50 / p99	Nginx p50 / p99
1,000	0.8 ms / 2.1 ms	0.6 ms / 1.5 ms
10,000	1.2 ms / 4.8 ms	0.9 ms / 3.1 ms
50,000	3.5 ms / 18 ms	2.1 ms / 9.2 ms

At 1K connections, both are sub-millisecond at p50. The gap widens under extreme concurrency -- at 50K connections, Nginx's p99 is roughly half of Caddy's. If you're running a high-frequency trading API or a service that genuinely handles 50K concurrent connections on a single node, Nginx is the better choice. For the vast majority of web applications, Caddy's numbers are excellent and well within acceptable latency budgets.

TLS Handshake Performance

Metric	Caddy 2.9	Nginx 1.27
TLS 1.3 handshakes/sec	42,000	58,000
TLS 1.3 resumption/sec	68,000	82,000
OCSP stapling	Automatic	Manual config
Certificate management	Fully automatic	Manual / certbot

Nginx handles more TLS handshakes per second thanks to OpenSSL's optimized assembly routines. Caddy uses Go's crypto/tls, which is fast but not at the same level as hand-tuned C. The trade-off is that Caddy handles certificate provisioning, renewal, and OCSP stapling with zero configuration. With Nginx, you're setting up certbot cron jobs, configuring OCSP stapling directives, and debugging renewal failures at 3 AM.

Configuration Comparison

Configuration is where Caddy and Nginx diverge most dramatically. Here are equivalent setups for common tasks.

Reverse Proxying a Node.js App

Caddyfile:

example.com {
    reverse_proxy localhost:3000
}

nginx.conf:

server {
    listen 443 ssl;
    server_name example.com;

    ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256;
    ssl_prefer_server_ciphers off;

    location / {
        proxy_pass http://localhost:3000;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}

Two lines of Caddyfile versus 16 lines of nginx.conf. Caddy automatically provisions a TLS certificate from Let's Encrypt, enables HTTPS, redirects HTTP to HTTPS, and sets the correct proxy headers. Nginx requires you to obtain the certificate separately, configure TLS parameters, and add proxy headers manually.

Load Balancing Multiple Backends

Caddyfile:

example.com {
    reverse_proxy localhost:3001 localhost:3002 localhost:3003 {
        lb_policy round_robin
        health_uri /health
        health_interval 10s
    }
}

nginx.conf:

upstream backend {
    server localhost:3001;
    server localhost:3002;
    server localhost:3003;
}

server {
    listen 443 ssl;
    server_name example.com;

    ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;

    location / {
        proxy_pass http://backend;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }

    location /health {
        # Note: active health checks require Nginx Plus
        proxy_pass http://backend;
    }
}

Warning: Active health checks (where Nginx proactively pings backends) are an Nginx Plus feature. Open-source Nginx only supports passive health checks -- it marks a backend as down after failed client requests, not through periodic health probes. Caddy includes active health checks in its open-source version.

WebSocket Proxying

Caddyfile:

example.com {
    reverse_proxy /ws/* localhost:3000
}

nginx.conf:

location /ws/ {
    proxy_pass http://localhost:3000;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_set_header Host $host;
    proxy_read_timeout 86400;
}

Caddy handles WebSocket upgrades transparently. Nginx requires explicit Upgrade and Connection header configuration, and you need to set a long read timeout to prevent Nginx from closing idle WebSocket connections.

Rate Limiting

Caddyfile:

example.com {
    rate_limit {
        zone dynamic_zone {
            key {remote_host}
            events 100
            window 1m
        }
    }
    reverse_proxy localhost:3000
}

nginx.conf:

limit_req_zone $binary_remote_addr zone=api_limit:10m rate=100r/m;

server {
    listen 443 ssl;
    server_name example.com;

    location / {
        limit_req zone=api_limit burst=20 nodelay;
        proxy_pass http://localhost:3000;
    }
}

Both achieve per-IP rate limiting. Nginx's leaky bucket algorithm is well-understood and battle-tested. Caddy's rate limiting (via the rate_limit module) uses a sliding window approach. Nginx's implementation is more flexible with burst and nodelay parameters; Caddy's is more readable.

Automatic HTTPS: Caddy's Killer Feature

This is the single biggest reason teams choose Caddy. When you specify a domain name in your Caddyfile, Caddy automatically:

1. Provisions a TLS certificate from Let's Encrypt (or ZeroSSL as fallback)
2. Configures TLS 1.2 and 1.3 with secure cipher suites
3. Enables OCSP stapling
4. Redirects HTTP to HTTPS
5. Renews certificates before expiry (at 70% of certificate lifetime)
6. Handles certificate storage and coordination across multiple instances via the CertMagic library

With Nginx, each of these steps is manual. You install certbot, run it, configure a cron job for renewal, add ssl directives to your config, set up the HTTP-to-HTTPS redirect, and configure OCSP stapling. It works, but it's more operational overhead and more surface area for mistakes. I've seen production outages caused by expired certificates on Nginx setups where the certbot cron job silently failed. That category of outage doesn't exist with Caddy.

Plugin and Module Ecosystems

Feature	Caddy	Nginx (Open Source)	Nginx Plus
Plugin architecture	Go modules, compile-time	C modules, compile-time	Dynamic modules
Adding modules	xcaddy build	Recompile from source	Load dynamically
Community modules	~200+	~100+ third-party	Curated set
WAF	coraza-caddy (ModSecurity-compatible)	ModSecurity	NGINX App Protect
Auth	caddy-security (JWT, OIDC, SAML)	Basic auth, subrequest	JWT, OIDC
Caching	cache-handler module	proxy_cache (built-in)	Enhanced caching
Config API	REST API (built-in)	None	NGINX Plus API

Caddy's plugin system is more accessible. Writing a Caddy module means writing Go code and building with xcaddy. Nginx modules require C programming and recompilation. Caddy also exposes a built-in REST API for dynamic configuration changes without reloads -- something only available in the commercial Nginx Plus product.

Nginx Plus: When Commercial Makes Sense

Nginx Plus ($2,500/year per instance) adds features that close many gaps with Caddy: active health checks, dynamic reconfiguration API, session persistence, JWT authentication, and enhanced monitoring. For enterprises already invested in the Nginx ecosystem, Plus is a reasonable upgrade path. But at $2,500/year per instance, the cost adds up. Caddy offers many of these features -- active health checks, config API, JWT auth -- in its open-source version. For new deployments, it's hard to justify Nginx Plus when Caddy provides comparable functionality at no cost.

Memory and Resource Usage

Scenario	Caddy RSS	Nginx RSS
Idle (no connections)	28 MB	6 MB
1K active connections	85 MB	22 MB
10K active connections	185 MB	62 MB
50K active connections	520 MB	145 MB

Nginx uses roughly 3x less memory at every scale. Go's runtime, goroutine stacks, and garbage collector add overhead. On a modern server with 16+ GB of RAM, 520 MB versus 145 MB at 50K connections is irrelevant. On a 512 MB VPS or an edge device, Nginx's minimal footprint is a meaningful advantage.

Frequently Asked Questions

Is Caddy fast enough for production?

Yes. Caddy handles hundreds of thousands of requests per second on modest hardware. The performance gap with Nginx exists but is typically 5-15% for reverse proxy workloads. Unless you're operating at the scale of a CDN node or processing 50K+ concurrent connections on a single server, Caddy's throughput is more than sufficient. Companies like Fly.io and Cloudflare have used Caddy components in production at significant scale.

Can Caddy fully replace Nginx?

For 90% of use cases, yes. Caddy can reverse-proxy, load-balance, serve static files, handle WebSockets, terminate TLS, rate-limit, and compress responses. The remaining 10% involves niche Nginx modules (like the Lua/OpenResty ecosystem, RTMP streaming, or specific C-level extensions) that have no Caddy equivalent. If your deployment relies on OpenResty or the njs JavaScript module for complex request processing, Nginx remains the better choice.

How does Caddy handle certificate management in a cluster?

Caddy uses its CertMagic library to coordinate certificate management across instances. By default, certificates are stored on the local filesystem. In clustered deployments, you configure a shared storage backend -- Caddy supports Consul, Redis, DynamoDB, S3-compatible storage, and databases like PostgreSQL. One instance obtains the certificate, stores it in the shared backend, and other instances pick it up. This avoids duplicate ACME challenges and Let's Encrypt rate limits.

What is the Nginx Plus pricing model?

Nginx Plus costs $2,500 per instance per year for the base subscription. The higher tier with NGINX App Protect (WAF) runs $5,000 per instance per year. Volume discounts are available but typically require 10+ instances. For comparison, Caddy's open-source version includes features like active health checks, a config API, JWT auth, and dynamic upstreams that Nginx gates behind Plus.

Which server is better for containerized deployments?

Caddy's single-binary architecture and built-in config API make it slightly better suited for container environments. The official Caddy Docker image is 40 MB compressed. Nginx's Alpine-based image is 10 MB. Both work well in Kubernetes with ConfigMaps or mounted configs. Caddy's advantage is the API-driven config that lets you update routing without restarting the container. Nginx requires a reload signal (which is non-disruptive but still requires orchestration).

How do I migrate from Nginx to Caddy?

Start with a single service. Convert the Nginx server block to a Caddyfile -- most configurations are straightforward since the concepts (upstream, location, proxy_pass) map directly to Caddy directives. Test with the same traffic by running Caddy on a different port behind Nginx, then swap. The biggest adjustment is removing all certificate management automation (certbot, cron jobs, ACME scripts) since Caddy handles it. Expect the migration of a typical reverse-proxy config to take under an hour.

Does Caddy support HTTP/3 and QUIC?

Yes. Caddy has experimental HTTP/3 support built in. Enable it with the servers global option. Nginx added experimental HTTP/3 support in version 1.25.0, and it is considered stable as of 1.27. Both implementations use the QUIC transport protocol. Caddy's HTTP/3 uses the quic-go library (pure Go), while Nginx uses quictls (a fork of OpenSSL). In practice, both work well for HTTP/3 clients, but Nginx's implementation has broader production validation at scale.

Recommendation: Choose Based on Your Team and Scale

If you're starting a new project, running a small-to-medium team, or deploying services where operational simplicity matters more than squeezing out the last 10% of throughput -- use Caddy. The automatic HTTPS alone eliminates an entire category of operational risk. The Caddyfile is readable, the defaults are secure, and the plugin ecosystem covers most needs. You'll spend less time configuring your web server and more time building your application.

Choose Nginx when you need specific modules that only exist in the Nginx ecosystem (OpenResty/Lua, RTMP), when you're operating at extreme scale where the memory and latency differences matter, or when your team already has deep Nginx expertise and established tooling around it. Nginx's 20-year track record and massive knowledge base mean you'll find an answer to any problem in minutes. Both are excellent, production-grade servers. The worst choice is spending weeks deliberating -- pick one, ship, and revisit only if you hit a concrete limitation.