Nginx Cheatsheet

Serving Static Files

Use this Nginx reference while you build software engineering projects, review code for technical interview prep, or polish examples for a software engineer resume.

Minimal Static Site

server {
    listen 80;
    server_name example.com;

    root /var/www/example;
    index index.html;

    location / {
        try_files $uri $uri/ =404;
    }
}

try_files checks: exact file → directory (appends index) → 404.

Core Directives

Directive	Example	What it does
`root`	`root /var/www/html;`	Document root for the block
`alias`	`alias /data/img/;`	Replace the matched URI prefix with this path
`index`	`index index.html index.htm;`	Default files to serve for directory requests
`try_files`	`try_files $uri $uri/ /index.html;`	Try paths in order, fall through to last arg
`autoindex`	`autoindex on;`	Enable directory listing
`autoindex_exact_size`	`autoindex_exact_size off;`	Show human-readable sizes
`autoindex_localtime`	`autoindex_localtime on;`	Use server local time in listings

`root` vs `alias`

# root: appends full URI to the root path
location /img/ {
    root /var/data;       # serves /var/data/img/photo.jpg
}

# alias: replaces the matched prefix
location /img/ {
    alias /var/data/img/; # serves /var/data/img/photo.jpg
}
# With alias, always end the path in / when the location ends in /

MIME Types and Default Type

http {
    include       /etc/nginx/mime.types;   # Maps extensions → Content-Type
    default_type  application/octet-stream; # Fallback for unknown extensions
    types {
        text/markdown md;                  # Add a custom type
    }
}

Serving a Single-page App (SPA)

location / {
    root /var/www/app/dist;
    index index.html;
    try_files $uri $uri/ /index.html;   # All 404s fall back to index.html
}

Cache-Control Headers for Static Assets

location ~* \.(js|css|png|jpg|jpeg|gif|ico|svg|woff2?)$ {
    root /var/www/app;
    expires 1y;
    add_header Cache-Control "public, immutable";
    access_log off;   # Reduce log noise for assets
}

`expires` value	Behaviour
`off`	No `Expires` header added
`epoch`	Sets `Expires: Thu, 01 Jan 1970` (never cache)
`max`	Sets `Expires: 31 Dec 2037` (browser max)
`1y`, `30d`, `1h`	Relative to current time
`-1`	Always expired (`Cache-Control: no-cache`)

Directory Listing

location /downloads/ {
    root /data;
    autoindex on;
    autoindex_exact_size off;
    autoindex_localtime on;
}

Protecting Hidden Files

# Block access to dotfiles (.env, .git, .htaccess, etc.)
location ~ /\. {
    deny all;
    access_log off;
    log_not_found off;
}

Limiting Access by IP

location /admin/ {
    root /var/www/app;
    allow 192.168.1.0/24;
    allow 10.0.0.5;
    deny all;
}

Custom Error Pages

server {
    error_page 404 /404.html;
    error_page 500 502 503 504 /50x.html;

    location = /404.html {
        root /var/www/errors;
        internal;   # Not directly requestable by clients
    }
}

Sendfile and Performance

http {
    sendfile    on;     # Zero-copy file transfer via OS (default off)
    tcp_nopush  on;     # Send headers + beginning of file in one packet
    tcp_nodelay on;     # Disable Nagle for keepalive connections
}

Enable sendfile on for all static file serving — it bypasses userspace copy.