Nginx Basics Cheat Sheet

Nginx configuration structure, server blocks (virtual hosts), reverse proxy setup, location block matching, load balancing, and caching configuration.

Last Updated: May 1, 2025

Configuration Structure

/etc/nginx/nginx.conf

Main configuration file — worker_processes, events, includes

/etc/nginx/sites-available/

Store site configs here (create them)

/etc/nginx/sites-enabled/

Symlink from sites-available to enable a site

http { ... }

HTTP-level settings: gzip, keepalive, include mime.types

server { ... }

Define a virtual host (domain-based or port-based)

location { ... }

Match request URI and define behavior within server block

nginx -t

Test configuration syntax (always run before reload!)

nginx -s reload

Gracefully reload configuration (zero downtime)

Server Blocks (Virtual Hosts)

Item	Description
`listen 80;`	Listen on HTTP port 80 (default_server makes it default)
`listen 443 ssl;`	Listen on HTTPS with SSL/TLS
`server_name example.com;`	Match requests for this domain
`server_name *.example.com;`	Wildcard — match all subdomains
`server_name ~^(www\.)?(.+)$;`	Regex server name matching
`return 301 https://$host$request_uri;`	Redirect all HTTP to HTTPS

Reverse Proxy

proxy_pass http://backend:3000;

Forward requests to backend server

proxy_set_header Host $host;

Pass original Host header to backend

proxy_set_header X-Real-IP $remote_addr;

Pass client's real IP address

proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

Pass full proxy chain IPs

proxy_set_header X-Forwarded-Proto $scheme;

Pass original protocol (http/https)

proxy_read_timeout 60s;

Timeout for reading backend response

proxy_buffering off;

Disable buffering for streaming/long-polling

Location Block Matching

Item	Description
`location = /exact`	Exact match — highest priority (= prefix)
`location ^~ /prefix/`	Prefix match — stop searching regexes after match
`location ~ \.php$`	Case-sensitive regex match (~ prefix)
`location ~* \.(jpg\|png)$`	Case-insensitive regex match (~* prefix)
`location /`	General prefix match — lowest priority (catch-all)

Pro Tip: Use `nginx -t` to test config before reloading. Add `proxy_set_header Host $host` when proxying — without it, apps see localhost instead of real hostname.