Enabling Compression
1. Enabling Gzip
| Directive | Values | Description |
|---|---|---|
| gzip | on | off |
Enables or disables gzip compression for responses. Default is off. |
| gzip_types | Content-Type values | Defines MIME types that should be compressed. Default includes common text-based types. |
| gzip_min_length | Integer (bytes) | Minimum response size to compress. Default is 20 bytes. |
| gzip_comp_level | 1-9 | Compression level (1 is fastest, 9 is best compression). Default is 5. |
Example: Basic Gzip Configuration
server {
listen 80;
root /var/www/html;
gzip on;
gzip_types text/plain text/css application/json application/javascript text/xml application/xml;
gzip_min_length 1024;
gzip_comp_level 6;
location / {
try_files $uri $uri/ =404;
}
}
Note: Gzip compression is most effective for text-based content like HTML, CSS, JavaScript, and JSON. Binary files such as images or videos are not compressed by default.
2. Setting Gzip Compression Level
| Directive | Values | Description |
|---|---|---|
| gzip_comp_level | 1 to 9 |
Compression level (1 = fastest, 9 = best compression) |
Note: Higher compression levels increase CPU usage. Balance between compression ratio and performance.
3. Configuring Gzip Types
| Directive | Values | Description |
|---|---|---|
| gzip_types | text/plain, text/css, application/json, application/javascript, application/xml, text/xml, text/html |
Defines MIME types to compress. Default includes common text-based content types. |
Example: gzip_types configuration
server {
listen 80;
root /var/www/html;
gzip on;
gzip_types text/plain text/css application/json application/javascript application/xml text/xml text/html;
}4. Setting Minimum Length
| Directive | Values | Description |
|---|---|---|
| gzip_min_length | 1024 |
Minimum response size in bytes to compress. Default is 1024. |
Example: Configuring gzip_min_length
server {
listen 80;
root /var/www;
gzip on;
gzip_min_length 1024;
gzip_types text/plain text/css application/json application/javascript;
}5. Enabling Gzip Vary Header
| Directive | Values | Description |
|---|---|---|
| gzip_vary | on | off |
Enables sending the Vary: Accept-Encoding header to prevent caching issues with compressed content. |
Example: Enabling Gzip Vary Header
server {
listen 80;
server_name example.com;
gzip on;
gzip_vary on;
gzip_types text/plain text/css application/json application/javascript text/xml application/xml;
}
Note: The
Vary: Accept-Encoding header is essential when serving compressed content to ensure that proxies and browsers correctly handle cached versions of both compressed and uncompressed responses.
6. Configuring Gzip Buffers
| Directive | Values | Description |
|---|---|---|
| gzip_buffers | 4 4k | 8 8k |
Sets the number and size of buffers used for compressing responses. Default is 4 4k. |
Note: Increasing buffer size can improve compression efficiency but may increase memory usage.
7. Disabling Gzip for IE6
| Directive | Values | Description |
|---|---|---|
| gzip | on | off |
Enable or disable gzip compression. Default is off. |
| gzip_disable | string |
Disables gzip compression for specific user agents. Can be used to exclude IE6. |
Example: Disabling Gzip for IE6
server {
listen 80;
server_name example.com;
gzip on;
gzip_types text/plain text/css application/json application/javascript text/xml application/xml;
# Disable gzip for IE6
gzip_disable "MSIE [1-6]\.";
}
Note: IE6 has known issues with gzip-compressed content, particularly when handling certain headers. The regex
"MSIE [1-6]\." matches Internet Explorer versions 1 through 6.
8. Using Gzip Static
| Directive | Values | Description |
|---|---|---|
| gzip_static | on | off |
Enables sending precompressed .gz files if they exist. Requires gzip to be enabled. |
| gzip_static | always |
Sends precompressed files even if client does not support gzip. |
Example: Enabling gzip_static
server {
listen 80;
root /var/www/html;
location / {
gzip_static on;
gzip on;
gzip_types text/plain text/css application/json application/javascript;
}
}
Note: Precompressed files must be generated separately (e.g., using
gzip command or build tools) and placed alongside original files.
9. Configuring Brotli Compression
| Directive | Values | Description |
|---|---|---|
| brotli | on | off |
Enables or disables brotli compression. Default is off. |
| brotli_types | Content types to compress | Defines MIME types that should be compressed. Default includes text/html, text/css, application/json, etc. |
| brotli_comp_level | 1 - 11 |
Compression level (1 = fastest, 11 = best). Default is 6. |
| brotli_window | 1k - 32k |
Window size for brotli compression. Default is 512k. |
| brotli_min_length | Integer in bytes | Minimum response size to compress. Default is 20 bytes. |
Example: Basic Brotli Configuration
server {
listen 80;
root /var/www/html;
brotli on;
brotli_types text/plain text/css application/json application/javascript text/xml application/xml;
brotli_comp_level 6;
brotli_min_length 20;
location / {
try_files $uri $uri/ =404;
}
}
Note: Brotli compression is supported in Nginx 1.14.0+ and requires the
ngx_brotli module to be compiled in.
10. Setting Brotli Quality
| Directive | Values | Description |
|---|---|---|
| brotli | on | off |
Enables or disables Brotli compression |
| brotli_comp_level | 1 - 11 |
Compression level (1 = fastest, 11 = best compression) |
| brotli_window | 10 - 24 |
Window size in bits (larger = better compression, more memory) |
Example: Brotli Compression Configuration
server {
listen 80;
server_name example.com;
brotli on;
brotli_comp_level 6;
brotli_window 512k;
location / {
root /var/www;
index index.html;
}
}11. Configuring Brotli Types
| Directive | Values | Description |
|---|---|---|
| brotli_types | text/html |
Defines MIME types to compress using Brotli |
Example: Brotli Types Configuration
location / {
brotli on;
brotli_types text/html text/css application/json application/javascript;
}12. Understanding Compression Trade-offs
| Aspect | Description | Impact |
|---|---|---|
| CPU Usage | Compression requires CPU cycles to process content | Higher compression levels increase CPU load, potentially affecting performance |
| Bandwidth Savings | Compressed content reduces data size over the network | Significant reduction in bandwidth usage, especially for text-based content |
| Latency | Compression adds processing time before content is sent | Can increase initial response time, but reduces overall transfer time |
| Content Type | Text-based content (HTML, CSS, JS) benefits more from compression | Binary files (images, videos) often do not compress well or at all |
| Client Support | Most modern browsers support gzip, deflate, and brotli | Older clients may not support compression, leading to fallback behavior |
Compression Algorithms Comparison
- Gzip: Widely supported, good balance of compression ratio and speed
- Brotli: Better compression ratio, higher CPU cost, newer standard
- Deflate: Older standard, less common, limited browser support
Note: Brotli offers better compression ratios than gzip but requires more CPU resources. For high-traffic sites, the trade-off between CPU usage and bandwidth savings should be evaluated.